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QH 
I 



UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 



VOLUME IX 
1920-1921 



UNIVERSITY OF IOWA 
1921 






'/p.,. 



CONTENTS 

VOLUME IX 

No. 1. Birge, E. A. and Juday, Chancey. A limnological 
reconnaissance of West Okoboji. 

No. 2. Stoner, Dayton. Nesting habits of the hermit thrush 
in northern Michigan. 

No. 3. Trowbridge, A. C. The erosional history of the drift- 
less area. 

No. 4. Lindsey, A. W. The Hesperioidea of America north of 
Mexico. 

No. 5. Clark, A. H., Kathbun, Mary J., Boone, Pearl L., 
Shoemaker, C. K., Clark, H. L. Reports on the 
Crinoids, Ophiurans, Brachyura, Tanidacea and Iso- 
poda, Amphipods, and Echinoidea of the Barbados- 
Antigua expedition of 1918. 



FIRST SERIES No. 35 SEPTEMBER, 1920 

UNIVERSITY OF IOWA 
STUDIES 



STUDIES IN NATURAL 
HISTORY 



Volume IX Number 1 

A LIMN0L0GICAL RECONNAISSANCE OF 
WEST 0K0B0JI 

by 
E. A. BIRGE and CHANCEY JUDAY 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 

Issued monthly throughout the year. Entered at the post office at Iowa City, Iowa, 
at second class matter. Acceptance for mailing at special rates of postage provided 
for in section 1103, Act of October 3, 1917, authorized on July 3, 1018. 



UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 

Professor Charles Cleveland Nutting, M. A., Editor 



Continuation of Bulletin from the Laboratories of Natural History of 
the State University of Iowa 

Volume IX Number 1 



A LIMNOLOGICAL RECONNAISSANCE OF 
WEST 0K0B0JI 

by 
E. A. BIRGE and CHANCEY JUDAY 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 



A LIMNOLOGICAL RECONNAISSANCE OF 
WEST OKOBOJI 

E. A. Birge and Chancey Juday 
I— SITUATION, AREA, VOLUME 

Lake Okoboji lies in Dickinson county close to the north- 
ern boundary of Iowa ; it is situated in T. 99 N ; R. 36 and 
37 W. Its approximate position is lat. 43.35° N ; long. 95.13° 
W. The region adjacent to the lake is thickly studded with 
other lakes and lakelets. Two lakes of considerable size- 
East Okoboji and Spirit lakes — are connected with it. Be- 
sides these there are ten or more bodies of water, which 
are large enough to bear names, and smaller ponds and 
pondlets by the score. None of these bodies of water, except 
Okoboji lake, has any considerable depth. East Okoboji 
lake reaches a maximum depth of about 8 m. (26 ft.), but 
most of its area is less than 3 m. (10 ft.) deep. Spirit lake 
has a maximum depth of 7.6 m. (25 ft.), but much of the 
area is between 6 m. and 7.5 m (20 ft., 25 ft.) deep. Oko- 
boji lake has a maximum depth of more than 40 m. (132 
ft.) 1 and therefore differs widely from its two neighbors 
both in physical and biological characters. 

The following paper records the results of a limnological 
reconnaissance of the lake, July 28-August 2, 1919. The 
reconnaissance was made as part of the cooperative work 
done by the United States Bureau of Fisheries in connec- 
tion with the Wisconsin Geological and Natural History 
Survey. The present report is issued with the permission 
of the Bureau. The study was carried on at the Iowa Lake- 
side Laboratory, to which the authors are indebted for 
much help and many courtesies. 

i Dr. Tilton ('16 p. 96) reports a depth of 135 feet. But as nothing is said re- 
garding the calibration of his line, the maximum may still better stand at that found 
by the regular survey. 



4 IOWA STUDIES IN NATURAL HISTORY 

The region about lake Okoboji and the lake itself was 
surveyed by the civil engineering department of Iowa State 
College through its summer surveying camp. The camp 
was held there from 1905 to 1912, and the topography of 
the region and the hydrography of the larger lakes were 
surveyed. In 1913 a pamphlet was published by the Col- 
lege (Ford '13) giving the methods employed, together with 
maps showing the results. Among the maps are a topo- 
graphical map of the region on a scale of 1 in. to 5100 ft., 
and a map giving the soundings in Okoboji lake on a scale 
of 1 in. to 2500 ft. The College also kindly furnished us 
with a blue print map of the lake, scale 1 in. to 1000 ft., 
which was used in all measurements. This map was repro- 
duced in the Iowa report on lakes and lake beds on a scale 
of about 1 in. to 2030 ft. In this report about one page of 
description is given to the lake and its area is stated as 
3788 acres (Iowa '16, p. 56, map No. 18) * The area thus 
given is accepted in this paper. 

The small scale map of the lake gives all of the sound- 
ings, numbering 732, or about 48 per sq. km. The large 
scale map gives a selection of these, numbering 261. The 
soundings were taken from a motor boat which was kept 
constantly in motion. Its position at the moment of sound- 
ing was signalled to two observers on shore who kept the 
boat constantly in sight with transits. By this method the 
position of the boat could hardly have been determined with 
minute accuracy, especially in the deeper water, and the 
maps give no dot or other similar indication of the precise 
position of the soundings. It is known that the small area 
which contains the deepest soundings lies somewhat to the 
west of the place indicated on the map. Under these con- 
ditions no attempt was made to plat the soundings omitted 
on the large scale map. In drawing the contours for the 
hydrography a 20-foot interval was used, since there are not 
enough soundings along the shores to warrant the use of 
a 10-foot interval. 

The areas included in the several contours were measured 
with the planimeter, with the following result : 

* Note: Appended to this article as Plate I. 



A LIMNOLOGICAL RECONNAISSANCE 5 

TABLE 1— AREA OF OKOBOJI LAKE— ACRES 
(From map, scale 1 m.=l,000 ft.) 

Area at surface 3788 acres 

" 20 feet 2750 



40 

60 

80 

100 

120 

132 



.1629 

973 

326 

114 

9 





Note: The surface area is taken from the report of the state high- 
way commission, 1916, p. 56. 

The contour map and the measurements show that the 
main slope of the bottom of the lake is fairly uniform to 
the depth of 80 ft., but that below this depth the slopes are 
decidedly steeper. In fact, the form of the basin is such 
as to lead the observer to expect a maximum depth of about 
90 ft. or 100 ft. Instead of this, however, a small area ex- 
tends to a depth of 132 ft., or 30 ft. to 40 ft. more than 
would be expected. 

From the data thus secured a hypsographic curve of the 
lake was platted and from this were derived the areas cor- 
responding to 5 m., 10 m., etc. From these data there were 
computed the area, volumes, etc., of the lake in metric units, 
as shown in the following table. The same data computed 
in cubic yards, etc., directly from the areas of the 20-ft. 
levels give substantially the same results. 

TABLE 2— OKOBOJI LAKE— GENERAL FEATURES 
Length, 8.79 km; 5.46 mi. 
Greatest breadth, 4.57 km; 2.84 mi. 
Direction of main axis, north and south. 
Area, 1535 ha; 3788 a. 
Greatest depth, 40.2 m; 132 ft. 
Mean depth, 12.3 m; 40.4 ft. 
Volume, 188,340,000 cu. m; 246,340,000 cu. yds. 
Length of shore line, 29.3 km; 18.2 mi. 
Shore development, 2.13. 
Volume development, 0.92. 
Mean slope of bottom, 1°34'; 2.74%. 

NOTES: The mean depth is found by dividing the volume by the 
area of the surface. The volume of the several strata are computed 

from the formula (a+B+ V^Ab)^ in wWch A is the area ° f the 
upper surface of the stratum, B is the area of the lower surface and 
H the vertical distance between the surfaces — in this case 5 meters. 



IOWA STUDIES IN NATURAL HISTORY 



By shore development is meant the ratio of the periphery of the 
water to the circumference of a circle of equal area. 
The mean slope is computed from the formula 



S=J 1 / 2 I +I 1 +I 2 +I 3 +I n -1 +%I n 1*L 



H 
j A~ 

In this formula S=mean slope; I , 1^ etc.=length of contour lines 
from surface to bottom; n=number of such contours; H=maximum 
depth; A=area of the lake. (See Juday '14, p. 123). 

TABLE 3— DETAILS OF OKOBOJI LAKE 





Area 




Area 


Volume 










between 
contours 






Depth 


Ha. 


Per cent 


Stratum 


Cubic 


Per cent 


meters 




of total 


meters 


Ha. 


meters 


of total 





1535 


100.0 


0-5 


330 


68,310,000 


36.3 


5 


1205 


78.5 


5-10 


402 


49,900,000 


26.5 


10 


803 


52.3 


10-15 


274 


33,100,000 


17.6 


15 


529 


34.5 


15-20 


214 


20,880,000 


11.1 


20 


315 


20.5 


20-25 


198 


10,360,000 


5.5 


25 


117 


7.60 


25-30 


67 


4,O20;OOO 


2.1 


30 


49.9 


3.25 


30-35 


35.3 


1,520,000 


0.8 


35 


14.6 



0.95 



35-40.2 


14.6 


250,000 


0.1 


40 


188,370,000 





The volume development is the ratio of the volume of a 
lake to that of a cone of equal base and height. If the lake 
were a tank with vertical sides the volume development 
would be three. Since in this case the volume development 
is less than 1.00, the volume of the lake is smaller than that 
of a cone of equal base and altitude. 

This condition is rarely found in lakes, especially in lakes 
of considerable depth, and it constitutes the main peculiar- 
ity of the basin of lake Okoboji. In most lakes there is a 
steep slope on the sides below the level to which the work 
of the waves extends and a nearly flat bottom. In such a 
lake the volume exceeds that of the cone with which it may 
be compared. In order that this condition may be better 
appreciated a comparison is made between Okoboji lake and 
lake Geneva, Wisconsin — a lake of somewhat larger area 
but not much exceeding Okoboji in depth. The area of 
lake Geneva is 2210 ha. ; its maximum depth is 43.3 meters ; 
its mean depth is 19.7 m; and its volume development 1.41. 
The instructive comparisons are those of percentage of 
volume and area at certain depths. 



A LIMNOLOGICAL RECONNAISSANCE 



TABLE 4— COMPARISON OF OKOBOJI AND GENEVA LAKES. 

See Fig. 1. 



Depth, 


Area at depth; 


Volume below depth; 


meters 


per cent 


per cent 




Okoboji 


Geneva 


Okoboji 


Geneva 





100.0 


100.0 


100.0 


100.0 


5 


78.5 


80.0 


64.7 


77.1 


10 


52.3 


68.5 


37.9 


58.3 


15 


34.5 


61.0 


20.1 


41.8 


20 


20.5 


50.7 


8.9 


27.6 


25 


7.6 


39.0 


3.1 


16.2 


30 


3.25 


29.3 


0.9 


7.6 


35 


0.95 


14.1 


0.1 


2.2 


40 


0.00 


2.7 


0.0 


0.2 


43.3 




0.0 







nJ to'f* /O 20 30 +Q 



SO 



60 



SO 



™-j°a&, 




40 



<4S 



•4S 



Fig. 1. Percentile hypsographic curves of lake Okoboji (O) and Geneva lake (G). 
These curves show the area of the lake basin at any depth, as a percentage of the 
area of the surface. See Table 4. 

The difference between the lakes is striking. The area 
of the basin of Okoboji lake is reduced to one-half that of 
the surface just below 10 meters ; in Geneva lake the same 
reduction is found below 20 meters, and this in spite of the 
fact that the areas of the two lakes at 5 meters are an al- 



8 IOWA STUDIES IN NATURAL HISTORY 

most equal per cent of the surface. Half of the volume of 
Okoboji lake is found above the depth of about 7.5 m., while 
the same volume lies at the depth of 12.5 m. in lake Geneva. 
Seventy-five per cent of the volume of lake Okoboji lies 
above the level of 13.8 m., while in lake Geneva the same 
level lies about 7 m. deeper, at 21 m. 

The small volume of the deeper water in Okoboji lake has 
an important bearing on the temperature of the lower 
water, and so on the mean temperature and on the quantity 
of heat absorbed by the lake during the open season. 

In computing the quantity of heat taken in by the lake, 
it is necessary to know one more physical constant, viz., the 
reduced thickness of the strata, or the thickness of any 
given stratum of water if its area is made equal to that of 
the surface. The mean depth is the reduced thickness of 
the entire lake, i. e., it is equal to the depth of a vertical 
sided tank necessary to hold all the water of the lake, if its 
area is equal to that of the lake's surface. It is convenient 
for various purposes of computation to select strata as thin 
as one meter, especially near the surface and in the thermo- 
cline. The volume of such thin strata cannot be computed 
accurately from the soundings, nor is such accuracy need- 
ful. The percentile areas at m., 5 m., etc., are platted on 
coordinate paper and connected by a smooth curve. Then 
the percentages indicated at the middle of each meter of 
depth will give the reduced thickness of that stratum in 
centimeters. From the same curve the reduced thickness 
of any other stratum can also be derived. 



A LIMNOLOGICAL RECONNAISSANCE 



TABLE 5— REDUCED THICKNESS OF THE SEVERAL STRATA 
OF OKOBOJI LAKE STATED TO THE NEAREST 
CENTIMETER 



Depth m. 


RT. cm. 


Depth m. 


RT. cm. 


0-1 


98 


20-25 


67 


1-2 


94 


25-30 


26 


2-3 


89 


30-35 


10 


3-4 


84 


35-40.2 


1.6 


4-5 


80 445 






5-6 


75 




6-7 


70 






7-8 


65 






8-9 


60 






9-10 


55 325 






10-11 


51 




11-12 


46 






12-13 


43 






13-14 


40 






14-15 


37 217 






15-16 


33 




16-17 


30 






17-18 


27 






18-19 


24 






19-20 


21 135 













In order to appreciate more fully the peculiarities of the 
basin of lake Okoboji, the reduced thickness of its several 
strata may be compared with those of lake Geneva, Wis. 

TABLE 6— REDUCED THICKNESS OF THE SEVERAL 5 m. 
STRATA OF LAKE OKOBOJI AND LAKE GENEVA, 
STATED IN CENTIMETERS 



Depth m. 


Okoboji 


Geneva 


0-5 


445 






451 


5-10 


325 






370 


10-15 


217 






325 


15-20 


135 






280 


20-25 


67 






225 


25-30 


26 






170 


30-35 


10 






106 


35-bottom 


1.6 


(40.2 


m.) 


43 (43.3 m.) 



Total 



12.266 



19.70 



It will be seen that the upper 5 m., of the two lakes have 
nearly the same reduced thickness and therefore an equal 
relative volume; but that the relative volume of the lower 
strata is much greater in lake Geneva. The 15-20 m. stra- 
tum of Geneva has a relative thickness more than twice as 



10 IOWA STUDIES IN NATURAL HISTORY 



great as that of Okoboji ; the 20-25 m. stratum is more than 
three times as thick; the thickness of the 25-30 m. stratum 
is five times, and that of the 30-35 m. stratum ten times as 
great as are the corresponding figures for Okoboji. The 
effect of this difference on temperatures is that the lower 
water of Okoboji lake has a higher temperature and a less 
quantity of heat than would be the case in the lake basin of 
ordinary form. 

II— TEMPERATURES 

TABLE 7— TEMPERATURE OBSERVATIONS ON OKOBOJI LAKE, 
1919 



Depth, 


I 

vii 29 


11 

vii 30 


Ill 

vii 31 


meters 


4.00 p 


8.45 a 


10.45 





25.0 


24.7 


24.6 


1 

2 _ 


24.0 


24.4 





3 




4 • _ 




5 


24.6 


6 

7 











8 




9 


24.2 


10 


23.7 


23.1 


23.8 


11 


23.2 

20.4 


22.3 
21.0 




12 


18.0 


13 


18.2 
15.6 


16.6 
15.6 




14 





15 


14.1 


14.7 


14.8 


16 





13.8 





17 





18 

19 

20 





12.9 





12.5 


12.1 


12.1 


25 





11.2* 


11.2 


30 








11.0 


34 








10.8 



* 23.5 m. 

Series No. 1 was taken in the mouth of Miller's Bay. 
Series No. II near the deepest water, which could not be placed on 
that day. 

Series No. Ill in deepest water found. 

In the evening of July 29 the hot weather was broken by 
squalls with rain and the wind shifted to the north, return- 
ing to south on July 30 and 31. The weather continued cool 
and the surface temperature fell, while that at 5 m. and 10 
m. rose. The computations are based on the observations of 



A LIMNOLOGICAL RECONNAISSANCE 11 

July 30, supplemented by those of July 31 for depths below 
20 m. 

TABLE 8— TEMPERATURE OF OKOBOJI LAKE, JULY 30, 1919 
Depth, 
meters Temperature 

2"?a 24 - 6 ° 

5-10 23.9° 

10-15 18.8° 

15-20 13. r 

20-25 11.6° 

25-30 11 1° 

30-35 . Z 10!9° 

35-40.2 10.8° 



Mean 21.00° 



From the observations in table 7, a temperature curve 
may be platted, as shown in Fig. 2 ; and from such a curve 
the mean temperature of each one-meter stratum may easily 
be derived. The figure shows a normal curve, with a 
strongly marked thermocline, beginning at 11 m., and end- 
ing at 15 m. There was a fall of 4.4° between 12 m., and 
13 m., and only 1.9° between 13 m., and 15 m. The total 
fall between 11 m. and 15 m. is 7.6°. In the observation 
on the 29th there was a decline of 9.1° in the same distance. 
Such variations are of constant occurrence in a lake; and 
if the thermocline of lake Okoboji is defined as the zone 
within which the temperature falls as much as 1.0° per 
meter, it will be found to vary from 4 m. to 6 m. in thick- 
ness. The irregularity shown at 14 m. to 16 m., on the 30th 
should not influence us to limit the zone to 3 m. or extend 
it to 5 m. for this occasion. 

The mean temperature in table 8 is computed as follows : 
The mean temperature of the several 5 m. strata is multi- 
plied by the per cent of volume of that stratum, as shown 
in table 3. The sum of these products gives the mean tem- 
perature of the lake as 20.996°, or, as stated, about 21.0*. 
This is an exceptionally high mean temperature for a lake 
of the area and depth of Okoboji. It is due to the high tem- 
perature and small volume of the lower water ; and the first 
of these causes is itself largely due to the second. 



12 IOWA STUDIES IN NATURAL HISTORY 

We may state therefore that the mid-summer tempera- 
ture of Okoboji lake in 1919 was close to 21° C. 

Quantity of Heat. From the data thus stated it is pos- 
sible to compute the quantity of heat represented by this 
rise of temperature to 21°. If this gain is to be stated there 
must be a starting point from which the gain may be com- 
puted. This obviously is not zero, as no lake has so low a 
temperature. As stated in another paper (Birge '15, p. 
170), there are two methods of stating the gains of heat. 
One is the annual heat budget, which takes as its starting 
point the mean temperature of the water immediately after 
the time of freezing, or, less accurately, at any time during 
the ice-period. The other is the summer heat-income, which 
starts from the temperature of 4°C. — that of the maximum 
density of water. For reasons stated in the paper referred 
to, the conclusions to be drawn from either of these methods 
are much the same. In all cases the gains between the win- 
ter temperature and 4° must be discussed apart from those 
above 4°. In the case of Okoboji lake we are limited to the 
summer heat-income, since the winter temperatures are still 
unknown. The gains of heat are stated in gram calories 
per square centimeter of the surface of the lake. A rise of 
1° in a stratum 100 cm. thick represents a gain of 100 cal. 
per sq. cm. of surface. 

The formula for computing the summer heat-income is 
(T-4) • RT; in which T is the mean temperature of any 
stratum and RT the reduced thickness of the stratum stated 
in centimeters. If the lake is considered as a unit, RT is 
the mean depth. In this case the mean temperature is 21.0° 
and the mean depth 12.3 m., or more exactly 1227 cm. The 
summer heat-income is therefore (21-4) • 1227=20849 cal., 
or approximately 21,000 cal. per square centimeter of the 
surface. 

The value of the summer heat-income will vary slightly 
with the stratum used in the computation. If the computa- 
tion is made by 5 m. strata the result is the same as that 
from the mean temperature, as the following table shows : 



A LIMNOLOGICAL RECONNAISSANCE 



13 



TABLE 9— SUMMER HEAT-INCOME, OKOBOJI LAKE 



Depth, | 




1 






meters 


T-4 


RT cm. 


Calories 


Percent 


0-5 


20.6 


445 


9167 


44.0 


5-10 


19.9 


325 


6468 


31.0 


10-15 


14.8 


217 


3242 


15.4 


15-20 


9.1 


135 


1228 


5.9 


20-25 


7.6 


67 


509 


2.4 


25-30 


7.1 


26 


185 


0.9 


30-35 


6.9 


10 


69 


0.3 


35-40 


6.8 


1.6 


11 


[ 0.1 



20849 



100.0 



This result, as well as that of the preceding table, gives 
the number of calories in a volume of water whose base is 
1 sq. cm., and whose total height is equal to the mean depth 
of the lake. 

If the computation is made by single meters in the upper 
water, the result is somewhat larger, as the following table 
of the upper 20 meters shows: 

TABLE 10— SUMMER HEAT-INCOME BY SINGLE METERS 

m.-20 m. 



Depth 
meter 


T-4 


RT cm. 


Calories 




0-1 


20.7 


98 


2029 




1-2 


20.7 


94 


1946 




2-3 


20.6 


89 


1833 




3-4 


20.5 


84 


1722 




4-5 


20.4 


80 


1632 


9162 


5-6 


20.3 


75 


1522 




6-7 


20.2 


70 


1414 




7-8 


20.0 


65 


1300 




8-9 


19.6 


60 


1176 




9-10 


19.2 


55 


1056 


6468 


10-11 


18.7 


51 


954 




11-12 


17.6 


46 


810 




12-13 


14.8 


43 


636 




13-14 


12.0 


40 


480 




14-15 


11.0 


37 


407 


3287 


15-16 


10.2 


33 


337 




16-17 


9.4 


30 


282 




17-18 


9.0 


27 


243 




18-19 


8.6 


24 


206 




19-20 


8.3 


21 


174 


1242 



In table 10 the calories in the 10 m.-15 m. stratum and 
in the 15 m.-20 m. stratum are greater when computed by- 
single meters than when the mean of the five temperatures 



14 



IOWA STUDIES IN NATURAL HISTORY 




Fig. 2. Temperature, summer heat-income, and reduced thickness of Okoboji lake. 
The curve RT gives at any point the reduced thickness in centimeters (p. 8) of a 
stratum one meter thick whose center is at that point. The curve cal. gives the 
summer heat-income per meter of depth corresponding to the temperature curve. It 
is given in calories per square centimeter of the surface. It is derived from the two 
other curves by the formula (T-4) : RT. See p. 12. 

is multiplied by the sum of the five RT's. The reason is 
obvious : The temperatures in the upper part of the stratum 
are above the mean and are multiplied by the larger num- 
bers representing the reduced thickness. The temperatures 
in the lower part of the stratum, which are as much below 
the mean as the others are above it, are multiplied by the 
smaller RT. The result is to make the sum of the calories 
greater in the 10 m.-15 m. stratum by as much as 75; in 
the others the difference is small since the change of tem- 
perature is not so great. The larger amount is the more 
accurate, since it gives proper weight to smaller units of 
thickness, but in general the difference is not worth noting. 
In each case the summer heat-income of Okoboji lake would 
be stated as about 21,000 cal. in 1919. The more accurate 
total is convenient to use in discussing the distribution of 
heat. Employing single meters to 20 m. and 5 m. intervals 
below that depth, it is 20,933 cal. 



A LIMNOLOGICAL RECONNAISSANCE 15 

The Distribution of Heat. Each square centimeter of the 
surface of lake Okoboji absorbs 20,933 cal. out of the heat 
delivered to it by the sun after the water has reached 4* ; 
and this heat is distributed through the water of the lake 
in a manner shown by the temperature curve in Fig 2. The 
length of the warming period is not known from observa- 
tion, but probably this lake, like lake Mendota, reaches the 
temperature of 4° about April 15 and continues to gain heat 
in the average year until August 15, although very little is 
gained after August 1. The sun should deliver about as 
much heat at Okoboji as at lake Mendota, since their lati- 
tude is practically the same and Okoboji is about 5.8° far- 
ther west. We may therefore assume that Okoboji lake, 
like Mendota, receives about 60,000 cal. per sq. cm. of sur- 
face during the period when the summer heat-income is 
gained, or about 54,000 cal. to August 1. If the lake, there- 
fore, gains about 21,000 cal., it lays up about one-third of 
its total receipts of heat and about 40% of its receipts to 
August 1. The remainder is partly reflected; it is partly 
used in evaporation, and much of it is returned to the air 
during the night and whenever the temperature of the air 
falls. 

It is possible to follow the distribution of the heat re- 
ceived by the surface through the water of the lake, as is 
shown by the following table : 



16 IOWA STUDIES IN NATURAL HISTORY 

TABLE 11— DISTRIBUTION IN DEPTH OF SUMMER HEAT-IN- 
COME STATED IN CALORIES PER SQUARE CENTI- 
METER OF THE SURFACE OF THE LAKE 





Depth meters 


Calories 







20933 




1 


18904 




2 


16958 




3 


15125 




4 


13403 




5 


11771 




6 


10249 




7 


8835 




8 


7535 




9 


6359 


> ' • 


10 


5303 




11 


4349 




12 


3539 




13 


2903 




14 


2423 




15 


2016 




16 


1679 




17 


1397 




18 


1154 




19 


948 




20 


774 




25 


265 




30 


80 




35 


11 




40.2 






It must be noted that this table and the account of the 
heat exchanges of the lake in general take no account of the 
heat which passes through the water and goes into the mud 
of the lake. It is obvious, for example, that if the bottom 
water at the deepest part of the lake stands at a tempera- 
ture above 10° for months, no small quantity of heat must 
pass through it into the mud ; and this heat must ultimately 
be supplied from the surface. At less depths the passage 
of heat into the bottom mud or sand must be even more 
rapid since the temperature of the water is higher. The 
number of 21,000 cal. does not represent the total heat 
which passes through the water of the lake, but that which 
remains in the water. Nothing is known about the mud 
temperature of Okoboji lake, or indeed of any lake, except 
Mendota; and information is far from complete regarding 
that. Perhaps 10% is a fair estimate of the addition which 
should be made if the heat of the mud is to be accounted 
for. This statement is not made with any idea of making 



A LIMNOLOGICAL RECONNAISSANCE 17 

further use of so rough an estimate, but that the table may 
not seem to imply that no heat whatever passes the 40.2 m. 
level. 

For certain purposes it is necessary to state the amount 
of heat at each level in terms of the area at the depth in 
question rather than in those of the surface. The number 
of calories, for instance, passing through each square centi- 
meter of the lake at the depth of 10 m. is equal to the num- 
ber of calories given in table 11 divided by the per cent of 
the surface area which is found at 10 m., as is shown in 
table 3. The following table gives the result : 

TABLE 12— CALORIES PER SQUARE CENTIMETER AT CER- 
TAIN DEPTHS STATED IN TERMS 
A-of the surface of the lake 
B-of the area at the depth in question 



Depth 


Area % 


Cal. A. 
20933 


Cal. B. 





100.0 


20933 


5 


78.5 


11771 


15000 


10 


52.3 


5303 


10140 


15 


34.5 


2016 


5840 


20 


20.5 


774 


3780 


25 


7.60 


265 


3490 


30 


3.25 


80 


2460 


35 


0.95 


11 


1160 



From tables 11 and 12 it appears that nearly one-half of 
the heat-income remains in the upper five meters of the 
lake; that more than half of the remainder is left between 
5 m. and 10 m. ; that more than 90% is found above 15 m. ; 
and that little more than 1% of the income is delivered into 
the water which lies below 25 m. 

On the other hand, table 12, B shows that there is a very 
considerable amount of heat delivered to each square centi- 
meter of the several 5 m. planes of the lake. At the depth 
of 30 m., for instance, there are found only 80 cal. per sq. 
cm., out of the 21,000 cal. which passed each sq. cm. of the 
surface. Brit through each sq. cm. of the 30 m. plane there 
passed 2460 cal. 

If that part of the lake below 30 m. be considered as a 
lake by itself, its area (table 3) is 49.6 ha.; its volume 



18 IOWA STUDIES IN NATURAL HISTORY 

1,770,000 cu. m. ; its maximum depth 10.2 m. ; and its mean 
depth |^-1 is 357 cm. Its mean temperature is nearly 

10.9°, so that T-4 nearly equals 6.9° ; and this temperature 
multiplied by the mean depth equals 2463 cal., or substan- 
tially the result shown in table 12 for the heat-income. 

The Transportation of Heat. All of the heat accumulated 
by the lake comes from its surface. Even that which is 
brought in by ground water enters ordinarily at the sur- 
face or very close to it and in a lake so large as Okoboji 
the contribution of heat from the ground water — which is 
plus or minus, according to the time of year — is so small 
as to be negligible. The temperature of the water in the 
well at the Lakeside Laboratory was 11.3° on July 30. 

There are two agents by which the heat of the summer 
heat-income may be conveyed from the surface to the deep- 
er water of the lake. It may be (a) delivered directly by 
the sun to the deeper strata of water, since the water is 
not opaque; or (b) it may be conveyed by the action of the 
wind, causing waves and currents by which the water 
warmed at the surface of the lake is carried downward and 
mingled with the colder water. It will be seen that in a 
lake of the type of Okoboji the latter method is by far the 
more important. 

It will be well to assume at first that the distribution of 
heat is wholly due to wind and later to estimate the contri- 
bution of the sun to this task. 

So long as the temperature of the water is below 4° there 
is no trouble in conveying the warmed surface water down- 
ward, for it becomes heavier as it warms and it consequent- 
ly sinks. The excess weight is very small and unless aided 
by wind the downward movement and consequent mixture 
would be slow. But wind is not lacking in early spring and 
even a light breeze is efficient in causing mixture of the 
water if gravity aids it. 

But when the temperature of the surface water passes 4* 
it becomes lighter as it warms and apart from the action 
of the wind it would remain floating on the colder and there- 



A LIMNOLOGICAL RECONNAISSANCE 19 

fore heavier water below. The wind causes both waves and 
currents ; the former efficient in mixing the surface strata ; 
the currents piling up the warmer water on the leeward side 
of the lake, mixing it with the colder water below it and in 
spring even setting the whole mass of water in the lake into 
a sort of rotation. Thus the warmer and lighter water is 
forced downward and mixed with the lower and colder 
strata and heat is thereby conveyed from the surface into 
the lake for a greater or less distance. Such an operation 
clearly involves work against gravitation. 

We shall see that direct insolation is confined to the upper 
water and that it is quite inappreciable below the depth of 
ten meters. The bottom water therefore, which at thirty- 
five to forty meters may have the temperature of 10.8°, 
owes all heat above 4° to the action of the wind. How much 
work is involved in such warming? The process has not 
been done at once, but in numerous stages, and the net 
amount of work may be represented by the amount of en- 
ergy necessary to push down through water at its maximum 
density a stratum of water of the smaller density possessed 
by water at 10.8°. If the density of water at 4° is taken as 
1.000,000, that of water at 10.8° is 0.99652 ; one liter has 
lost by warming 348 mg. in weight. For each liter there- 
fore of warmed water carried from the surface to the 35 
m.-40 m. stratum a weight of 348 mg. must be moved a 
mean distance of 37.5 meters. If the volume of the stratum 
is known, the amount of work can easily be computed. 

There is, however, a more convenient method of computa- 
tion. Since the heat is expressed in calories per square 
centimeter of the surface the work needed to distribute it 
is best expressed in the same way. Then the volume of a 
stratum is represented by its reduced thickness stated in 
centimeters, which is equivalent to the weight in grams of 
a column of water whose base is a square centimeter and 
whose height is the reduced thickness of the stratum. The 
formula for computing the work is 

RT-Dm-(1.000,000-D) 
in which RT is the reduced thickness of the stratum stated 
in centimeters and therefore equal to the weight in grams 



20 IOWA STUDIES IN NATURAL HISTORY 

of a column whose base is one square centimeter. Dm is 
the distance in centimeters from the surface to the middle 
of the stratum, and (1.000,000-D) is the loss of weight as 
a decimal fraction of unity. 

In Okoboji lake the values are in the example taken 
RT of 35 m.-40m.=1.6 cm. (table 5) 
Dm=3750 cm. 
(1-D) =0.000,348 

The result is 2.088 ; that is, the transport of the warmed 
water from the surface to the 35m.-40 m. stratum calls for 
2.088 gram-centimeters of work per square centimeter of 
the lake. In this computation no account is taken of the 
viscosity of the water as a hindrance to mixture. 

In this way the work needed by each stratum may be 
computed. The value of RT-Dm would be computed once 
for all for each stratum of the lake likely to be needed ; it 
is called in later tables the factor for that stratum. In gen- 
eral we compute it by single meters to 20 m. and by 5 m. 
intervals below that depth. The value of (1-D) is taken 
from a table. (See Birge '16, p. 391). 

In this way is computed the value of the direct work as 
shown by the following table : 

TABLE 13— OKOBOJI LAKE. DIRECT AND DISTRIBUTED 
WORK, JULY 30, 1919 



A 


B 


C 


D 


E 


F 


G 


H 


Stratum 


Temp. 


Factor 


1-D 


Gem. 








0-1 


24.7 


49 


2853 


13.96 




246.41 




1-2 


24.7 


141 


2853 


40.18 




218.91 




2-3 


24.6 


222 


2827 


62.83 




192.97 




3-4 


24.5 


294 


2802 


82.32 




167.60 




4-5 


24.4 


360 


2777 


100.04 


299.37 


145.79 


971.68 


5-6 


24.3 


412 


2752 


113.30 




124.50 




6-7 


24.2 


455 


2727 


124.22 




105.67 




7-8 


24.0 


488 


2677 


130.78 




86.41 




8-9 


23.6 


510 


2579 


131.58 




69.91 




9-10 


23.2 


522 


2483 


129.46 


629.34 


53.35 


441.84 


10-15 


18.8 


2879 


1581 




422.90 




132.22 


15-20 


13.1 


2332 


0611 




143.99 




38.44 


20-25 


11.6 


1475 


0431 




63.57 




8.41 


25-30 


11.1 


715 


0378 




27.03 




2.78 


30-35 


10.9 


325 


0358 




11.64 




0.96 


35-40.2 


10.8 


60 


0348 




2.09 




0.14 




1599.93 


1596.47 



Notes: 1. In Col. C, two ciphers 00 are omitted at the right of 



A LIMNOLOGICAL RECONNAISSANCE 



21 



each number. In Col. D, 0.00 is omitted at the left of each number; 
the significant figures only being employed in each case. 

2. Multiplication is done by Crelle's tables, using three significant 
figures. The difference in the total of direct and distributed work is 
due to omitting some of the final figures in multiplying. 

3. The direct work in the 10 m.-15 m. and 15 m.-20 m. strata is 
the sum of the work of the single meters, as is the case in the strata 
above. It is therefore not exactly the product of the numbers in 
Cols. C and D. 

4. Col. C, Factor, gives the product RT • Dm for each stratum. 
Col. D, 1-D, gives the significant figures showing the loss of density. 
1.000,000 — D. Col. E gives the amount of work per square centimeter 
of surface of the lake, necessary to raise the stratum from 4° to the 
temperature stated by mixture of warm water from the surface. 



J$ 








SO 








too 








/so 








20O 








ZSO/ 






'^, 














































^* 


*J3 










***, 


^ 




















"*N 




































««« 


^ 


















> 






































N 


X 












/ 












































N 


V 






y 


r> 






















s 
























N 




* 




















































\ 






















































\ 










































2" 














F 






































/? 














■ 


1 
























to 




























/ 
















































.-* 


S 














































,«** 


"' 
















































s 


>" 


















































/ 




















































/ 


f 














































j 






/ 
/ 
















































/ 




/ 






















































/ 
/ 
















































£Q* 


1 




f 
















































V/3 


f£ 


G 
















































<° 



Fig. 3. Curves showing the direct work, the distributed work, and the effect of direct 
insolation. See pp. 19-26. The curves extend to the depth of 20 meters. The entire 
area enclosed by the curve of distributed work, ABDEH, is equal to that of the direct 
work, AGGH. The area, ACDB, gives the direct effect of the sun, and the area, 
ACDEH, that of the wind. 

The table shows that about 1600 g. cm. of work per sq. 
cm. of surface of the lake were needed to distribute 21,000 
cal. per sq. cm. through the water of the lake. The upper 
and warmer strata of the lake required most of this work. 
The deeper strata needed very little. The reasons for this 
are found partly in the small volume of the lower strata, 
partly in their lower temperature, and partly in the fact 



22 IOWA STUDIES IN NATURAL HISTORY 

that the loss of density per degree is much less at lower 
temperatures than at higher ones. A full statement of this 
fact and its results may be found in Birge '10, pp. 989-1004. 

Table 13, Col. E shows the work done in behalf of each 
stratum or the work needed to carry the warmed water 
down from the surface and put it in place. Most of the work 
therefore is done outside of the stratum which is to be 
warmed. In the case of the 5 m.-lO m. stratum two-thirds 
of the 629 g. cm. would be needed to bring the warmed 
water to the top of the stratum and one-third to distribute 
it through the stratum. In a similar way each upper stra- 
tum has its share of the work for all of those below it. It 
is possible, by a somewhat tedious computation to ascertain 
the amount of work done in each stratum. The method and 
details of this computation are shown in Birge '16, p. 354. 
The results for Okoboji lake are given in table 13, columns 
G and H, and show the distributed ivork. 

It appears that 971 g. cm., or nearly two-thirds of the 
whole work are done in the upper 5 m. This amount of work 
is needed to carry to a depth of 5 m. the heat which goes 
to the strata below 5 m., and to distribute through the m.- 
5 m. stratum the heat which remains there. Similarly, 442 
g. cm. of work are done in the 5 m.-lO m. stratum. 

The Role of the Sun. In this discussion of the distribution 
of heat it has been assumed that all warming below the 
surface is done by mixture ; that the warmed water is taken 
from the surf ace. and distributed by the wind. This assump- 
tion is, of course, incorrect as it implies that the water is 
opaque to the sun's radiation. It is necessary therefore to 
ascertain what aid the sun may give in the distribution of 
heat. 

From data so small in quantity as those available for lake 
Okoboji this question can be answered very imperfectly. In- 
deed, the data can tell us only the possible maximum con- 
tribution of the sun to the work of distributing heat. 

Observations were made on July 29 with the pyrlimni- 
meter, an instrument for measuring the penetration of solar 
radiation into the water of the lake and its absorption by 
the water. It consists essentially of 20 small thermal 



A LIMNOLOGICAL RECONNAISSANCE 23 

couples which can be alternately exposed to the sun and 
covered. The electric current caused by the sun during ex- 
posure is measured by a d'Arsonval galvanometer. The 
swing of the galvanometer is directly proportional to the 
heat energy in the solar radiation. If, therefore, the ther- 
mal couples are exposed first at a depth of one meter below 
the surface and then at a depth of two meters, the ratio of 
the two readings will give the rate at which the stratum of 
water transmits the solar radiation incident on its upper 
surface. 

Readings were made in Okoboji lake to the depth of four 
meters with the result shown in the following table: 

TABLE 14— OKOBOJI LAKE. READINGS OF PYRLIMNIMETER, 
11.10-11.27 LOCAL TIME. SKY CLEAR. TRANSPAR- 
ENCY OF WATER BY SECCHFS DISC, 3.1 m. 

Depth, cm. Divisions Cal. Percent Depth Transmission, 
of air per cent 



Air 


219.0 


1.53 


100.0 







50 


48.5 


0.34 


22.0 






100 


33.5 


0.23 


15.3 


100-200 


54 


200 


18.0 


0.13 


8.2 


200-300 


54 


300 


9.5 


0.067 


4.4 


300-400 


53 


400 


5.0 


0.035 


2.3 







Notes : The column marked divisions gives the swing of the galva- 
nometer when the thermal couples are exposed to the sun. The column 
marked Cal. gives the value of these readings in calories per square 
centimeter per minute. The fourth column shows the value of the 
readings in the water as a percentage of the readings in the air. The 
last column shows the rate at which a stratum of water one meter 
thick transmits the solar radiation incident on its upper surface. 

It appears that under the conditions of the observation 
about 15.3% of the solar radiation reaching the surface of 
the lake was present at the depth of 100 cm. Nearly 85% 
therefore was either lost or absorbed before reaching that 
depth. Such a result is a common one in lakes. The radia- 
tion at 100 cm. rarely exceeds 20% of the total radiation 
and often falls far below 15%. In absolutely pure water 
some 43% may remain at that depth. But the stains al- 
ways dissolved in lake water and the particles of organic 
and inorganic matter suspended in it rapidly cut off the 
radiation. 

It appears also that below the depth of one meter, about 
53%-54% of the energy which reaches the surface of each 



24 IOWA STUDIES IN NATURAL HISTORY 

one-meter stratum is transmitted to the surface of the next 
one-meter stratum. Stated in terms of absorption, about 
46%-47% of the energy of the solar radiation present at any 
depth below one meter is absorbed in passing through a 
stratum of that water one meter thick. Thus it appears 
that only a small fraction of the solar radiation penetrates 
the lake to the depth of one meter and that this small 
amount is very rapidly absorbed. 

If we assume that the conditions present at the time of 
observation are average ones, we may compute the general 
role of the sun in distributing heat. For this purpose we 
estimate as before that the sun delivers to the lake 60,000 
cal. cm. 2 during the warming season. We take from the 
pyrlimnimeter reading that 22% of this reaches a depth of 
50 cm. ; that 15% penetrates to the depth of 100 cm. ; and 
that the transmission below 100 cm. is 54% per meter. The 
result is then as follows : 

TABLE 15— HEAT DELIVERED TO THE SURFACE OF THE 
LAKE DURING THE WARMING SEASON AND THE 
AMOUNT DELIVERED TO VARIOUS DEPTHS BY 
DIRECT INSOLATION. STATED IN CALORIES PER 
SQUARE CENTIMETER OF HORIZONTAL SURFACE 

Depth Cal. 

Air 60,000 

50 cm. 13,200 



100 
200 
300 
400 
500 
600 
700 
800 
900 
1000 



9,000 

4,860 

2,620 

1,440 

760 

410 

220 

120 

65 

35 



Table 15 shows in a very striking way how the direct in- 
fluence of the sun is confined to the surface strata. At the 
depth of 5 m., for instance, there would be directly delivered 
only 760 cal. during the entire warming season of four 
months, or only about 6 cal. per day. The total is less than 
may be delivered to the surface in a day. At the same rate 
of transmission only 35 cal. would reach the depth of 10 m. 



A LIMNOLOGICAL RECONNAISSANCE 25 

in four months, or about as much as may reach the surface 
in twenty minutes at noon. 

It is obvious that this computation is not based on average 
conditions, since on the one hand the reading was made near 
noon, when the sun was at a high altitude, and on the other 
hand it was far from the zenith and the path of its rays 
through each meter of depth would be more than 100 cm. 
It is quite possible to determine the energy present at 100 
cm. and the rate of transmission if the sun were vertical ; 
and it is also possible from this new curve to determine the 
same data for the mean conditions during the warming 
period. The computation has been made with the follow- 
ing result: 

Energy at 100 cm. Transmission 
Observed, July 29 15.3% 53%— 54% 

Vertical sun 16.0% 56%— 57% 

Mean sun, (Apl. 15-Aug. 15) 14.2% 50%— 51% 

It would be possible to use the computed mean sun in the 
following work instead of the observed data. But the dif- 
ference is not great, and the result is at best only a rough 
approximation. The value of the mean sun is based on five 
years of observation at Madison, Wis., in the same latitude 
as Okoboji. 

Effect of Direct Insolation. We may now go on to com- 
pute the direct effect of the sun on the distribution of heat. 
We have as data (1) the downward movement of heat 
amounting to 20,933 cal. cm. 2 at the surface (table 11) »; 
(2) the amount of work needed to distribute this heat 
(table 13, G) ; (3) the heat directly contributed by the sun 
to various depths (table 15) . The following table gives the 
result : 



26 



IOWA STUDIES IN NATURAL HISTORY 



TABLE 16— CONTRIBUTION OF THE SUN TO THE DISTRIBU- 
TION OF HEAT 



Depth cm. 


Cal. 


Sun 


Per cent 





20933 


20933 


100.0 


50 


20300 


13200 


65.0 


100 


19800 


9000 


45.5 


200 


19600 


4860 


26.1 


300 


17400 


2620 


15.1 


400 


16300 


1410 


8.6 


500 


15000 


760 


5.1 


600 


14100 


410 


2.9 


700 


13100 


220 


1.7 


800 


12100 


120 


1.0 



Note: The calories which pass through each square centimeter are 
stated in terms of the area at that depth, in the column headed Cal. 
The direct radiation which reaches the lake bottom, say between 100 
cm. and 200 cm. depth, is not available for warming the deeper water. 
The contribution of the sun must therefore be measured as a fraction 
of the energy passing through each sq. cm. of the depth in question 
and not in terms of the surface of the lake. 

It appears, therefore, that the sun may contribute 9000 
cal. of the 19,800 cal. which pass through each square centi- 
meter of the one-meter level ; that it can contribute only 760 
cal. at five meters of the 15,000 cal. which pass that level ; 
and that at eight meters only one per cent of the heat comes 
directly from the sun. 

This is the maximum possible contribution if the observa- 
tions represent average conditions, as they doubtless do 
approximately. The results assume that none of the heat 
due to direct insolation is lost ; that for instance all of the 
9000 cal. delivered by the sun during the warming season 
to the depth of one meter are part of the summer heat-in- 
come, none being lost to the lake by cooling at night or dur- 
ing cool periods. This assumption is manifestly far too 
favorable to the sun, but at present we have no data on 
which to correct it accurately. 

The data of table 16 may be applied to Fig. 3 and a curve 
drawn through the points thus determined. Then the area, 
ABDEH, represents the total work done in distributing the 
heat to the depth of 25 m. ; the area, ACDB, represents the 
contribution of the direct insolation to the work of distribut- 
ing heat on the assumption that no sun-placed heat is lost ; 
and the area, ACDEH, represents the contribution of the 



A LIMNOLOGICAL RECONNAISSANCE 27 

wind on the same assumption. The areas may be measured 
with a planimeter, with the following result : 

TABLE 17— CONTRIBUTION OF SUN AND WIND TO DISTRIB- 
UTING HEAT ON THE ASSUMPTION THAT NO 
SUN-PLACED HEAT IS LOST 

Depth Per cent of work 

Sun Wind 

Total 20.3 79.7 

m.-5 m. 31.6 68.4 

5 m.-lO m. 3.8 96.2 

m.-l m. 66.3 33.7 

1 m.-5 m. 20.0 80.0 
Below 1 m. 12.1 87.9 
Below 5 m. 2.6 97.4 

It thus appears that the maximum possible contribution 
of the sun to the distribution of heat is about 20%. Of this 
about 95% is in the upper 5 m. of the lake. The sun con- 
tributed only about 2.6% to the distribution of heat below 
five meters, and practically nothing below ten meters. 

The actual contribution of the sun is less than this. If 
we assume that the percentage of sun-placed heat lost is the 
same as the average loss, the figure of 20% will be reduced 
to 7%-8%, since only about one-third of the sun's radia- 
tion is absorbed by the lake. This is certainly too low an 
estimate of the sun as heat placed at depths of 2. m. or 3 m., 
or even at 1 m. would be lost far less easily than that in the 
upper centimeters of the water. Perhaps no better estimate 
can be made at present than to assume that the contribu- 
tions of the sun below 1 m. is a fair amount and that direct 
insolation is responsible for 10% — 12% of the work of dis- 
tributing heat and that the wind furnishes 88% — 90%. 

With such estimates we must leave the subject at present. 
Future studies will be able to furnish greater accuracy, but 
no result is likely to show that the wind furnishes much 
below 80% or much above 90% of the work needed in the 
distribution of the summer heat-income through the water 
of lake Okoboji. 

Ill— OTHER TEMPERATURE OBSERVATIONS ON 
OKOBOJI LAKE 

The point has been emphasized that the small volume of 
the lower water of Okoboji lake gives rise to exceptionally 



28 IOWA STUDIES IN NATURAL HISTORY 

high temperatures near the bottom. In 1919 the bottom 
temperature at 34 m. was 10.8° and was probably 10.7° or 
10.6° at 40 m. This must be an exceptionally low tempera- 
ture for the lake since lakes in the same general region had 
unusually low bottom temperatures in 1919. This situation 
was due to a period of hot calm weather in June, which heat- 
ed the surface stratum of the lakes and thereby checked the 
distribution of heat to the lower water. The bottom tem- 
perature of lake Mendota on August 1 at 23.5 m. was 9.5°, 
the lowest recorded ; and that of Green lake was 4.9° at 72 
m., the only temperature below 5.0° found by the Wisconsin 
survey in this lake. That of lake Geneva was 7.0°, a low 
temperature, but not the lowest on record. The general 
temperature, however, of the water below 10 m. was the 
lowest recorded. 

Temperature observations on lake Okoboji were made by 
Professor John L. Tilton, of Simpson College in 1915 and 
1916 (Tilton '16, '17). The record of August 5, 1915, 
showed a temperature of 15.5°C. (59.8°F.) at a depth of 
about 35 m. (115 ft.). On the same date the surface tem- 
perature was 20.0°C. (68°F.). On July 13 the temperature 
at 35 m. was 15.0°C. and at about 41 m. (135 ft.) 14.7°C. 
These observations were made with a minimum thermo- 
meter weighted and sunk into place. 

In 1916 Professor Tilton took readings in June and July. 
On July 18 he found a temperature of 13.1°C. at 32 m. This 
series was read with a Leeds and Northrop electrical re- 
sistance thermometer. This instrument became disabled and 
on July 26 readings were made with the minimum thermo- 
meter, showing a temperature of 15.6° at a depth of 27 m. ; 
the reading at this depth on July 18 was 13.3°. 

The attention of the authors of the present paper was 
called to Okoboji lake by this work of Professor Tilton. The 
readings at first seemed incredible. Nothing in our pre- 
vious experience warranted the idea that a lake could have 
a midsummer temperature greater than 15° at a depth of 
40 m., or even a temperature approximating 15°. Lake 
Geneva, the nearest parallel in depth, had shown in 18 sea- 
sons a mean bottom temperature of 8.0° with a minimum 



A LIMNOLOGICAL RECONNAISSANCE 29 

of 5.6° and a maximum of 10.0°. The temperature of Oko- 
boji was therefore nearly twice as high as the mean of lake 
Geneva. The maximum gain of Geneva above 4° was 6°, or 
about one-half that of Okoboji. 

There is no reason to doubt that Dr. Tilton's observations 
show the general character of the lake's temperature. He 
corrected his minimum thermometer for pressure, which at 
135 ft. would have caused a rise of 0.24°C. This correction 
is not made in the figures given above. The temperature of 
the lower water of all lakes in this region was exceptionally 
high in 1915, in most cases at a maximum. This was due 
to the low temperature of the air during May, June, and 
July, which favored the distribution of heat. 

The air temperatures at Madison were as follows : 

Mean 1915 1916 

May 14.2° 11.1° 14.0° 

June 19.6° 16.5° 16.5* 

July 22.4° 20.0° 26.5* 

There is only one year on record in which the tempera- 
ture of May was lower than in 1915. June was the coldest 
on record in both 1915 and 1916, and July, 1915, was the 
coldest since 1891. May, 1916, was practically at the mean, 
while July was much above the mean. Under these con- 
ditions we should expect to find unusually high bottom tem- 
peratures in lakes during both years. This condition was 
present in the Wisconsin lakes. Lake Geneva had a bottom 
temperature of 9.8° in August, 1915. This is the highest 
on record except in 1917 when it rose to 10.0°. In that year 
the temperature of May and June was the same as in 1915, 
and the first half of July was also cold. 

There is therefore no reason why the records from Oko- 
boji lake in 1915 and 1916 should not be accepted as show- 
ing the general situation. 

On the other hand it does not seem probable that they 
are exactly accurate. The readings of 1915 near the bot- 



torn are as follows : 




100 ft. 


60.0°F. 


110 " 


56.5T. 


115 " 


59.8'F. 



30 IOWA STUDIES IN NATURAL HISTORY 

Here is apparently a drop of nearly 2.0°C. in about three 
meters followed by a rise of about 1.8°C. in 1.5 m. Such 
changes at this depth are highly improbable and lead one 
to query whether the thermometer functioned accurately. 
If the 110-ft. reading is to be taken as correct, the bottom 
temperature is 13.6°; if we take the 115-ft. reading it is 
15.5°. It may be added that the amount of the oxygen 
found by us in the lower water forbids the idea of a pos- 
sible rise of the bottom temperature due to fermentation. 
(See p. 42). 

The observations of July 26, 1916, are open to the same 
criticism. The readings on that date show the following : 

18 m. 17.6° 

19 m. 16.8° 

20 m. 18.6° 

21 m. 17.1° 

22 m. 16.5° 

Such irregularities are unprecedented. It is not easy to 
see how a temperature of 18.6° could be reached at 20 m. 
with much lower temperatures at 19 m. and 21 m. 

Another though somewhat similar query arises regard- 
ing the 1916 series. There is no objection to accepting 
13.1° as a correct reading at 32 m. on July 18 and 13.3° at 
27 m. on the same day. These readings were made with 
the Leeds-Northrop instrument. But if these are correct 
it is hard to see how we can accept the readings by the 
minimum thermometer on July 26. This gives a tempera- 
ture of 15.6° at 27 m. or a rise at that depth of 2.3° in eight 
days. These days were bright hot days with little wind, 
according to weather records at Madison. 

In this case the criticism is not based on the idea that 
the temperature reported is impossibly high; on the con- 
trary it seems quite within the possible limits. The diffi- 
culty is to see how so great gains of heat could have been 
made in the week available for them. 

The thermocline was well established on July 18 and 
therefore conditions would be as unfavorable as possible 
for the distribution of heat to the lower water. Still fur- 
ther the record of the minimum thermometer on July 26 



A LIMNOLOGICAL RECONNAISSANCE 31 

shows large gains at all depths as compared with July 18. 
The total gains to the depth of 25 m. amount to nearly 2600 
cal. per sq. cm. of surface, or more than 300 cal. per day. 
This sum must be considerably more than half the heat de- 
livered by the sun, which at Madison averaged 460 cal. for 
the days in question. A gain of this magnitude in July 
seems impossible. Such gains are not infrequently made 
in April when the temperature of the water is low, so that 
distribution of heat is easy and when it is also above that 
of the air so that losses from the surface are at a minimum. 
In July the mean daily gain of lake Mendota is 69 cal. and 
in July, 1915, it was 97 cal. It seems clear therefore that 
the apparent rise of temperature between July 18 and July 
26 can not be a real one. It is possible, since the volume 
of the bottom water is so small, that it may be displaced 
by wind in such a way as to cause this apparent rise, or the 
apparent fall between June 28 and July 18. (Tilton '17, 
p. 39). If so, these oscillations of temperature are excep- 
tionally great and are themselves worth study. 

The alternative conclusions can not be avoided, either 
that Okoboji lake is exceptional to a wholly unprecedented 
degree, or that the readings of the minimum thermometer 
need further correction. It is best therefore to defer de- 
tailed discussion of them until a careful study has been 
made of the heat exchanges of the lake. In reaching this 
conclusion we ought not to fail to recognize the great serv- 
ice done to limnology by Dr. Tilton's observations. He 
recorded for the first time the bottom temperatures in a 
deep lake whose basin is of such form as to give rise to 
very high temperatures at the bottom. He thus showed 
where exceptional opportunity lay for the study of the ef- 
fect of the form of the basin on the temperature of lakes 
and perhaps in other respects. 

We may be pardoned an illustration of the influence of 
Dr. Tilton's records. There is in Wisconsin a small body of 
water, Rock lake, whose dimensions are: Area, 496 ha.; 
maximum depth, 20.4 m. ; mean depth, 6.1 m. ; volume devel- 
opment, 0.90. (Juday '14, p. 34, map VII). It is therefore 
almost a morphometric copy of Okoboji lake on a small 



32 IOWA STUDIES IN NATURAL HISTORY 

scale. This lake had been sounded by this Survey but no 
temperature readings had ever been made in it. It was 
visited in August, 1918 in consequence of the work of Dr. 
Tilton and its bottom temperature was found to be 20.0°, 
while that of Mendota (a much larger lake) at the same 
time and depth was 13.0°. No reading approaching 20° had 
ever been made before at such a depth in any Wisconsin 
lake. It is plain that in this case also the form of the lake 
basin profoundly influences temperature. It may be added 
that in 1919 the bottom temperature, like that of Okoboji, 
was exceptionally low — 13.1°. 

IV. COMPARISONS OF TEMPERATURES IN LAKES 
OKOBOJI AND GENEVA 

While the bottom temperature of lake Geneva in 1919 was 
not as low as it has been on other years, the mean temper- 
ature is the lowest recorded — 14.2°, as compared with a 
16-year mean of 16.5°. The next lowest temperature was 
15.4° in 1897, so that in 1919 the water was 1.2° colder than 
in any other August on record. The low record of 1919 
was due to the temperature of the water below 10 m. since 
the epilimnion was by no means exceptionally cold on Au- 
gust 30, and earlier in the month it must have been quite 
up to the average. The most conspicuous difference was 
in the 10 m.-15 m. stratum which was 5.2° below the mean 
of 18 years. The thermocline showed a drop of 10.0° in 
three meters, from 21.0° at 9 m. to 11.0° at 12 m. This is 
a remarkable decline considering the direction and force of 
the wind which was from the northwest on August 30. 
This would tend to spread rather than to condense the iso- 
therms at the place of observation. The thin epilimnion 
is no doubt an inheritance from the hot weather in June 
and to this is due the low temperature of the 10 m.-15 m. 
stratum. 

The summer heat-income of Geneva as measured by the 
observations on August 30 is as follows : 



A LIMNOLOGICAL RECONNAISSANCE 33 

TABLE 18— TEMPERATURE AND SUMMER HEAT-INCOME OF 
LAKE GENEVA, WIS., AUGUST 30, 1919 

Depth Temp. CaL 

RT 

0-5 21.3 7802 

5-10 20.1 5957 

10-15 11.9 2568 

15-20 9.4 1512 

20-25 8.7 1058 

25-30 8.0 680 

30-35 7.4 360 

35-40 7.1 121 

40-43 7.0 12 



14.18 20070 



If the heat budgets of lakes are to be fairly compared 
there must be some common adjustment of the temperature 
of the epilimnion. This is rapidly affected by the tempera- 
ture of the air and the relative volume of the epilimnion is 
so great that its temperature has a large influence in de- 
termining the heat budget. In Okoboji lake in 1919 more 
than 75% of the summer heat-income was in the epilimnion 
and in lake Geneva nearly 70% was in the same stratum. 
If therefore a lake is visited at the close of a hot period the 
temperature of its epilimnion will be found to be high, and 
both the mean temperature and the summer heat-income 
will be correspondingly large; while a week later after sev- 
eral days of cool weather the epilimnion may have lost con- 
siderable heat. This is the case in the two lakes under con- 
sideration. The surface of lake Okoboji was at 24.7°, while 
that of Geneva was only 21.4°, and the difference in the 
m.-5 m. stratum amounted to nearly 1400 cal. in favor of 
Okoboji, due wholly to a difference in temperature which 
was itself largely due to the different dates on which the 
lakes were visited. On the other hand, the temperature of 
thermocline and hypolimnion in such lakes as these ordi- 
narily changes very little between the last week of July and 
the first of September. 

Our observations on Wisconsin lakes show that under 
similar conditions there is but little difference in the mid- 
summer temperature of the epilimnia of lakes in the same 
general region, whatever the size of the lake or the thick- 
ness of the stratum. Differences are especially small when 



34 



IOWA STUDIES IN NATURAL HISTORY 



lakes of the same order of size or depth are compared. In 
order therefore to eliminate so far as possible differences 
in temperature due to weather condition of short period and 
to employ temperatures which show the effects of the sea- 
son as a whole, we have been accustomed to assume a mid- 
summer temperature of the epilimnion at the average max- 
imum ordinarily reached. This for our lakes is 23°, so that 
T-4=19°. This temperature may ordinarily be assumed 
without any necessity of modifying the lower part of the 
temperature curve to fit the change in the upper part. 

The effect of this assumption in Okoboji and Geneva 
lakes may be seen from the following table, in which tem- 
peratures and calories below 10 m. remain as observed, but 
the epilimnion is given a temperature of 23°. This reduces 
the budget of Okoboji and raises that of Geneva. 

TABLE 19— SUMMER HEAT-INCOME OF OKOBOJI AND GENE- 
VA LAKES COMPARED WITH EPILIMNION AT 23° 







Okoboji 


1 




Geneva 




Depth, 


T-4 


RT 


Cal. 


T-4 


RT 


Cal. 


meters 














0-5 


19.0 


445 


8455 


19.0 


451 


8569 


5-10 


19.0 


325 


6175 


17.5 


370 


6475 


10-15 


14.8 


217 


3212 


7.9 


325 


2568 


15-20 


9.1 


135 


1228 


5.4 


280 


1512 


20-25 


7.6 


67 


509 


4.7 


225 


1058 


25-30 


7.1 


26 


185 


4.0 


170 


680 


30-35 


6.9 


10 


69 


3.4 


106 


360 


35-40 


6.8 


1.6 


11 


3.1 


39 


121 


40- 






| 


3.0 


4 
1970 


12 


Total 


19844 


21355 



Under these conditions the heat budget of Geneva is about 
1500 cal. larger than that of Okoboji, and most of the excess 
is in the lower water. The budget of Geneva below 15 m. is 
about 3740 cal. and that of Okoboji is 2000 cal. The larger 
volume of the lower water more than makes up for the 
lower temperatures of lake Geneva. In the 10 m.-15 m. 
stratum the reverse is true; here Okoboji has nearly 550 
cal. more than Geneva. T-4 is nearly twice as great, and 
this more than compensates for the smaller value of RT. 

The table therefore shows very clearly the effect of the 
volume of the lower water on heat gains. The temperature 



A LIMNOLOGICAL RECONNAISSANCE 



35 



of the water in the lake of greater volume is lower but the 
total quantity of heat is greater. 

The same point may be further illustrated by consider- 
ing the temperatures reported by Dr. Tilton for Okoboji 
in 1916 and comparing these with maximum temperatures 
for Geneva. 

TABLE 20— COMPARISON OF LAKE OKOBOJI AND GENEVA AT 
HIGH TEMPERATURES OF THE WATER. 





Okoboji 






Geneva 






July 26, 1916 






Sept. 8 


, 1899 






Observed 


Epi. 


at 23° 


Observed 


Epi. at 23° 


Depth, 


Temp. 


Cal. 


Temp. 


Cal. 


Temp. 


Cal. 


Temp. 


Cal. 


meters 


















0-5 


26.5 


10012 


23.0 


8455 


23.7 


8885 


23.0 


8569 


5-10 


24.7 


6728 


23.0 


6175 


23.7 


7289 


23.0 


7030 


10-15 


18.6 


3163 


18.6 


3163 


22.5 


6012 


22.2 


5915 


15-20 


17.2 


1782 


17.2 


1782 


15.4 


3192 


15.4 


3192 


20-25 


16.2 


817 


16.2 


817 


12.0 


1800 


12.0 


1800 


25-30 


15.4 


296 


15.4 


296 


10.2 


1054 


10.2 


1054 


30-35 


15.2 


112 


15.2 


112 


9.2 


551 


9.2 


551 


35-40 


15.0 


17 


15.0 


17 


8.6 


179 


8.6 


179 


40-43 










8.3 


17 


8.3 


17 




22927 


20817 


28979 


28307 



Compare first the budgets of Okoboji lake in 1919 (Table 
19) and 1916. They are approximately 21,000 and 23,000 
respectively — a difference of 2000 cal. If the temperature 
of the epilimnion is reduced to 23° they are 19,800 cal. and 
20,800 cal., respectively — a difference of 1000 cal. in favor 
of 1916. Yet in that year the temperature of the water 
below 15 m. averaged more than four degrees higher than 
in 1919 ; but as the total reduced thickness of the lake below 
15 m. is only 240 cm. this rise in temperature represents 
an income of only about 1,000 cal. cm. 2 of the surface. 

In lake Geneva we find a summer heat-income of about 
29,000 cal., in 1899, or, placing the temperature of the epi- 
limnion at 23°, an income of 28,300 cal. Thus Geneva may 
gain from 6,000 cal. to 7,000 cal. more than has been found 
in Okoboji, assuming the correctness of Dr. Tilton's record 
of 1916. 

Lake Geneva has been visited for so many seasons that 
we can hardly expect to find in its temperature a much 



36 IOWA STUDIES IN NATURAL HISTORY 

larger range of variations than has already been shown. 
We may therefore infer that the summer heat-income may 
range from about 20,000 cal. to 29,000 cal., or that with the 
epilimnion at the standard temperature of 23° the range 
will be from 21,000 cal. to 28,000 cal. Another 1000 cal. 
may be added to the maximum if we impose the warmest 
observed epilimnion on the warmest observed temperature 
for the lower water. 

In the case of Okoboji the limits are not thus known. 
Temperatures of 1919 are probably close to the minimum 
for the lower water, and therefore no heat-income is likely 
to be lower than 19,000 cal. to 20,000 cal, with the epilim- 
nion at 23°. But the volume of the lower water is so small 
that its temperature has very little influence on the heat- 
income ; and the same fact also brings it about that but little 
work is needed to raise the temperature of the lower water 
much above the minimum. In 1916 weather conditions 
were such as to favor a very high temperature. Yet the 
total heat-income (Table 20) was only 2000 cal. above that 
of 1919 at observed temperatures. A temperature much 
above that of 26.5° for the upper five meters is hardly to 
be expected ; a mean gain of one degree at all depths of the 
water below 10 m. means only 460 cal. total gains, and one 
degree in the hypolimnion below 15 m. means only about 
240 cal. Under such conditions we can hardly expect the 
maximum heat-income to rise much above 24,000 cal.-25,000 
cal. The latter figures would involve a mean temperature 
of the hypolimnion close to 20°, or more than 4° above that 
of 1916. 

Even such extreme temperatures do not seem excluded 
from possibility — at least not by the amount of work in- 
volved in the distribution of heat at such high tempera- 
tures. The distribution of heat in Okoboji in 1916 when 
the bottom water reached 15° required 1981 g. cm. ; the dis- 
tribution of heat in Geneva in 1899 demanded 2752 g. cm. 
or nearly 800 g. cm. more than that of Okoboji. It would 
thus seem possible for the wind to do more work on Oko- 
boji and under favorable circumstances raise the tempera- 
ture of the lower water above 15°. If we assume that the 



A LIMNOLOGICAL RECONNAISSANCE 37 

supply of heat and of wind were such as to add 4° to the 
temperature of each stratum below 10 m. (the temperature 
m.-lO m. remaining as in the 1916 series), the work 
would rise only to 2561 g. cm. — an amount which would 
seem within the limits of the capacity of Okoboji. Under 
these conditions the summer heat-income would be only 
24,690 cal., a small gain over 1916 or 1550 cal. for 581 g. cm. 
of work. Apparently, therefore a summer heat-income of 
about 24,500 cal. is a maximum for lake Okoboji. This in- 
come would involve a mean temperature of 24° for the water 
of the lake, and this would imply a mean temperature of 
about 20° for water in the 15 m.-40 m. region of the lake. 
The distributing agencies seem theoretically able to effect 
this. But it would require a rare conjunction of delivery 
of heat and efficiency of distribution to secure results much 
greater than those recorded in 1916. 

Systematic study of the lake, therefore, is required to 
show whether temperatures even higher than those of 1916 
are attainable in lake Okoboji. Such speculations as that 
just given have very little value, but they may be per- 
missible in the case of a lake so exceptional as Okoboji. 
The possibilities of life in the lower water of such a lake 
are profoundly influenced by these exceptional possibilities 
of temperature, and the lake therefore offers chances for 
unusual problems in the ecology of the plankton as well as 
similar problems in the physics and chemistry of lakes. 

V. DISSOLVED GASES 
West Okoboji lake belongs to the temperate type in which 
there are two circulation periods and two stratification 
periods each year; these periods correspond in general to 
the four seasons of the year. The water is in complete 
circulation for a time in the spring and again in the autumn, 
but it is in a state of stratification in summer and in win- 
ter. During the periods of complete circulation the tem- 
perature of the water is substantially uniform from surface 
to bottom and the dissolved substances are practically the 
same at all depths; but during stratification the water of 
the upper and lower strata show important thermal and 



38 IOWA STUDIES IN NATURAL HISTORY 

chemical differences which become more marked as the 
period of stratification advances. The differences which 
were found about the middle of the summer period of strati- 
fication in West Okoboji lake are shown in tables 7 and 21 
(pp. 10 and 44). 

Samples of water from the different depths of the lake 
were obtained by means of a water bottle and the carbon 
dioxide and dissolved oxygen were determined for the dif- 
ferent strata. The former was determined by the Seyler 
method, using phenolphthalein and methyl orange as indi- 
cators for the titrations with standard acid and alkali. The 
Winkler method was used for the determination of the dis- 
solved oxygen. (For descriptions of these methods see 
Birge and Juday, '11, pp. 13-23). 

CARBON DIOXIDE 

Carbon dioxide is usually present in lake waters in three 
different states ; that is, as fixed, half -bound, and free car- 
bon dioxide. The quantity of fixed and half-bound is de- 
pendent upon the amount of the substances present with 
which this gas is usually combined, chiefly calcium and mag- 
nesium. The fixed carbon dioxide is that portion which is 
held in a close chemical union, most generally with calcium 
and magnesium, and forms the carbonates of these sub- 
stances. The half-bound is held in a rather loose combina- 
tion by the carbonates, converting them into bicarbonates. 

In addition to these a lake water may hold in solution a 
certain amount of carbon dioxide in an uncombined state 
and this constitutes the free carbon dioxide. From the bio- 
logical standpoint the half-bound and free carbon dioxide 
are the most important since they constitute the sources 
from which the aquatic chlorophyllaceous organisms obtain 
their carbon dioxide for photosynthesis. No portion of the 
fixed carbon dioxide is directly available for photosynthesis, 
but indirectly the quantity of it is a very important factor 
because the amount of half-bound carbon dioxide is depend- 
ent upon the quantity of carbonates present in the water. 
In a water that gives a neutral or acid reaction with phe- 
nolphthalein it is assumed that the quantity of half-bound 
carbon dioxide is equal to that of the fixed. 



A LIMNOLOGICAL RECONNAISSANCE 39 

Fixed carbon dioxide. Table 21 shows that the quantity 
of fixed carbon dioxide in West Okoboji lake amounted to 
38.58 cc. per liter of water from the surface to a depth of 
14 m. Below this depth the amount was somewhat larger, 
ranging from 39.59 cc. at 15 m. to 41.20 cc. at 33 m, the 
bottom. 

At the close of the vernal period of circulation the quan- 
tity of fixed carbon dioxide is substantially the same at all 
depths ; but soon after the water becomes stratified in early 
summer there is an appreciable difference between the epi- 
limnion and the hypolimnion. There is a decrease of the 
fixed carbon dioxide in the upper water, due in part to the 
rise in the temperature of the water which tends to make 
the carbonates less soluble, and in part to the fact that the 
chlorophyllaceous organisms of this stratum draw upon the 
half-bound carbon dioxide. This process gives the water 
an alkaline reaction and thus tends to precipitate the car- 
bonates, more especially the calcium carbonate. The sub- 
merged aquatic plants growing in the shallow water, such 
as Chara, also remove a considerable amount of calcareous 
material from the upper water. 

The water of the hypolimnion soon comes to have a dis- 
tinctly acid reaction, which is due to the free carbon di- 
oxide that is liberated in the decomposition of organic mat- 
ter in this region and in the respiration of the various 
organisms that inhabit this stratum. Thus any carbonates 
that are precipitated in the upper water and sink into this 
region will be redissolved ; at the bottom where the water 
contains the largest amount of free carbon dioxide the fixed 
carbon dioxide is largest in amount because this acid water 
dissolves some of the calcareous material in the bottom mud. 
As the summer period of stratification advances the differ- 
ence in the fixed carbon dioxide content of the upper and 
lower water becomes more marked, the maximum differ- 
ence being found a short time before the autumnal overturn 
takes place. 

Half-bound carbon dioxide. When the water of a lake 
is neutral or acid in reaction to phenolphthalein the half- 
bound carbon dioxide is regarded as equal in amount to the 



40 IOWA STUDIES IN NATURAL HISTORY 

fixed carbon dioxide; but in waters which give an alkaline 
reaction the quantity of the latter is greater than that of 
the former. The excess of the latter is equivalent to the 
amount of free carbon dioxide that would be required to 
give the water a neutral reaction ; in table 21 the deficiency 
is indicated by a minus sign in the column showing the free 
carbon dioxide. 

Free carbon dioxide. The epilimnion is preeminently the 
zone of photosynthesis and where the chlophyl-bearing or- 
ganisms are abundant a rather large supply of carbon di- 
oxide is required for this process. The demand thus be- 
comes larger than the supply of free carbon dioxide and the 
organisms draw upon the supply of half-bound carbon di- 
oxide. Since this leaves an excess of normal carbonates the 
water has an alkaline reaction and the degree of alkalinity 
depends upon the amount of half-bound carbon dioxide that 
has been used. It has been found that more than 80% of 
the half-bound carbon dioxide may be thus utilized. 

As a result of the activities of the chlorophyl-bearing or- 
ganisms the epilimnion of Okoboji lake was distinctly alka- 
line at the time of these observations. (See table 21, p. 
44). This alkalinity was equivalent to 4.28 cc. of free car- 
bon dioxide ; that is, it would have required 4.28 cc. of this 
gas per liter to make this water neutral. The water at a 
depth of 5 m. showed the same degree of alkalinity as that 
at the surface; but at 10 m. it was distinctly less alkaline 
and became neutral at 13 m. 

The water of the hypolimnion gave a distinctly acid re- 
action; a maximum of 1.72 cc. of free carbon dioxide per 
liter was noted at 33 m. This is the usual condition in lakes 
of this type. Much decomposition takes place in this stra- 
tum which furnishes a constant supply of free carbon di- 
oxide and an additional amount is derived from the respira- 
tion of the organisms that inhabit this region. Since the 
water of the hypolimnion is cut off from the air during the 
stratification period and since this gas diffuses very slowly 
through water, there is very little loss of free carbon dioxide 
during such periods. As a result the lower water soon 
gives an acid reaction, even when it is distinctly alkaline 



A LIMNOLOGICAL RECONNAISSANCE 41 

at the time of stratification, and the free carbon dioxide 
shows an appreciable increase in quantity as the season 
advances; the largest amount is found at the bottom just 
before the overturn takes place. 

DISSOLVED OXYGEN 

During the vernal and autumnal periods of circulation 
this gas is also substantially uniform in its distribution 
from surface to bottom ; the largest amount is found at the 
close of the latter period because oxygen is more soluble in 
cold than in warm water. With the rise in the temperature 
of the water in the spring there is a corresponding decrease 
in the amount of oxygen but the water remains nearly or 
quite saturated with this gas as long as the vernal emula- 
tion continues. When stratification becomes established in 
early summer, however, it is soon followed by appreciable 
differences in the quantity of oxygen in the different strata. 

The temperature of the epilimnion continues to rise until 
the summer maximum is reached which means a decreased 
capacity for dissolved oxygen. Decomposition and respira- 
tion also tend to decrease the supply of this gas but the 
water of this stratum is kept in circulation by the wind and 
thus freely exposed to the air which tends to keep the supply 
near the saturation point. Another source of supply is the 
oxygen liberated in this stratum during the process of pho- 
tosynthesis. In general, then, the quantity of oxygen in 
the epilimnion does not fall very far below the saturation 
point during the summer period of stratification and, under 
favorable conditions, the stratum may even become super- 
saturated. 

On July 31, 1919, the dissolved oxygen in the epilimnion 
of West Okoboji lake amounted to 5.80 cc. per liter at the 
surface and 5.40 cc. at a depth of 10 m. While these quan- 
tities represent an abundant supply of this gas, neverthe- 
less they are both well below the point of saturation, the 
former being 95.5% and the latter only 86.6% of the amount 
required for saturation. This indicates that the water of 
the epilimnion was being depleted of its supply of oxygen 
through decomposition and respiration faster than it was 



42 IOWA STUDIES IN NATURAL HISTORY 

receiving this gas from the air and from the photosynthetic 
activities of the chlorophyl-bearing organisms. 

The hypolimnion remains practically uniform in tempera- 
ture after the formation of this stratum so that its capacity 
for oxygen is scarcely affected during the summer. On the 
other hand, however, it is cut off from contact with the air 
by the epilimnion and conditions are not favorable for 
photosynthesis at that depth ; it is thus deprived of the two 
main sources from which a supply of oxygen can be obtained 
and any decrease during the summer remains as a deficiency 
until the autumnal overturn takes place. Decomposition 
and the respiration of the organisms which occupy this 
stratum contribute to the decrease of the oxygen supply and 
the extent of this decrease depends upon the volume of the 
hypolimnion and upon the abundance of decomposable ma- 
terial and living organisms ; if the volume is relatively small 
and these two processes are fairly vigorous there will be 
a marked decrease in the supply of oxygen as the summer 
advances and a portion, or even practically all, of this 
stratum may be deprived of its dissolved oxygen. 

It will be noted in table 21 that the hypolimnion of Oko- 
boji lake possessed a relatively small amount of dissolved 
oxygen at the time of these observations ; the amount varied 
from 2.23 cc. per liter at 15 m. to 0.86 cc. at a depth of 33 m. 
At 18 m., however, the amount was a little more than half 
a cubic centimeter larger than at 15 m. Such differences 
have been noted in other lakes but the cause of the phe- 
nomenon has not yet been definitely ascertained. Stated in 
percentages the quantity of oxygen varied from 36.5 % of 
saturation at 18 m. to only 10.9% at 33 m. With such a 
marked decline in the dissolved oxygen at this stage of the 
summer stratification period it is safe to predict that this 
gas all disappeared from the lower portion of the hypolim- 
nion, at least, before the time of the autumnal overturn. 

In the mesolimnion, or thermocline, the quantity of oxy- 
gen declined from that of the epilimnion above to that of 
the hypolimnion below; that is, from 5.40 cc. per liter of 
water at 10 m. to 2.40 cc. at 13 m., while there was a fur- 



A LIMNOLOGICAL RECONNAISSANCE 43 

ther decline to 2.23 cc. at 15 m. Thus the greater part of 
the decrease took place in the upper half of the mesolim- 
nion. 

The last item in table 21 shows the results obtained on 
water from the well of the Lakeside Laboratory. This 
water had a temperature of 11.3°. It will be noted that 
there was an abundance of free carbon dioxide, about seven 
times as much as was noted in the lake water at a depth of 
33 m. It also contained almost two and a half times as 
much fixed carbon dioxide as the surface water of the lake. 
There was a fairly large supply of dissolved oxygen in this 
well water; the result shown in the table is undoubtedly 
too high since, in obtaining the samples, the water was ex- 
posed to the air as it was being pumped into the bottles. 

A set of observations on the dissolved gases of lake Men- 
dota was made on August 6, 1919, and the results are shown 
in table 22. The epilimnion of lake Mendota showed the 
same degree of alkalinity as that of West Okoboji lake, but 
the lower water of the former had a distinctly larger 
amount of free carbon dioxide. The epilimnion of lake Men- 
dota possessed a smaller amount of fixed carbon dioxide 
than West Okoboji lake, averaging about 5 cc. per liter less, 
but the difference in the hypolimnion was not so marked. 
The amount found at the bottom, 22 m., in the former lake 
was the same as that at 15 m. and 20 m. in the latter, while 
that at 15 m. and 18 m. in lake Mendota was the same as 
that in the upper water of West Okoboji lake. Both lakes 
belong to the "hard water" group, with the water of West 
Okoboji lake carrying a somewhat larger quantity of car- 
bonates in solution. 

A slightly larger amount of oxygen was found in the 
upper water of lake Mendota but there was a distinctly 
smaller amount in the hypolimnion than in West Okoboji 
lake. 



44 



IOWA STUDIES IN NATURAL HISTORY 



TABLE 21 — Observations on the dissolved gases of Okoboji lake, July 
31, 1919. In the column for free carbon dioxide the 
minus sign indicates that the water gave an alkaline re- 
action and the plus sign that it gave an acid reaction 
with phenolphthalein. 



Depth, 
meters 


! Carbon dioxide, 
cc. per liter. 


Oxygen J 




Free 


Fixed 


Cc. per 
liter. 


Per cent 
of saturation 





| — 4.28 


| 38.52 


| 5.80 


| 95.5 | 


5 


| — 4.28 


| 38.52 


| 5.42 


88.8 | 


10 


| — 3.21 


| 38.52 


| 5.40 


86.6 | 


12 


| — 1.07 


| 38.52 


| 3.46 


53.5 | 


13 


| Neut. 


| 38.52 


| 2.40 


36.0 | 


14 


| + 0.86 


| 38.52 


| 2.32 


32.3 | 


f 15 


| + 0.86 


| 39.59 


| 2.23 


| 30.7 | 


18 | 





| 2.75 


36.5 | 


20 


| + 1.29 


| 39.59 


| 1.75 


22.8 | 


25 ] 


1 


| 0.90 


11.5 | 


30 




I 


| 0.90 


1 H.5 | 


33 


I + 1.72 


1 41.20 


| 0.86 


| 10.9 | 


1 1 








| Well 


| 4-11.18 


| 94.16 


| 2.55 


| 32.7 | 



TABLE 22 — Observations on the dissolved gases of lake Mendota on 
August 6, 1919. In the column for free carbon dioxide 
the minus sign indicates that the water was alkaline and 
the plus sign that it was acid to phenolphthalein. 



Depth, 
meters 


Carbon dioxide, 
cc. per liter. 


Oxygen 




Free 


Fixed 


Cc. per 
liter. 


Per cent 
of saturation 





— 4.28 


33.70 


6.16 


100.7 


8 


— 4.28 


33.70 


5.21 


83.5 


10 


+ 0.86 


38.00 


1.40 


19.5 


13 


+ 0.86 


38.00 


0.64 


8.2 


15 


+ 1.92 


| 38.52 


| 0.52 


6.5 


18 


+ 2.58 


| 38.52 


| 0.20 


2.4 


( 22 


+ 2.58 


39.59 


| 0.10 


1 1.2 



VI. THE PLANKTON 

The small floating and free swimming organisms that 
constitute what is known as the plankton may be divided 
into two groups, namely, (a) those which are large enough 
to be easily obtained with the regular plankton net and (b) 
those which are so small that they readily pass through the 



A LIMNOLOGICAL RECONNAISSANCE 45 

meshes of the finest bolting cloth. The former constitutes 
what is known as the net plankton and the latter the nanno- 
plankton. Strictly speaking the latter term has been applied 
only to organisms whose maximum diameter does not ex- 
ceed 25 /*., but it is such a convenient term that it is pro- 
posed to extend its meaning to include all of the forms that 
escape through the meshes of the net. 

Methods. The net plankton was obtained by means of a 
closing net whose coefficient has been determined as 1.2; 
that is, about 83% of the column of water through which it 
is drawn passes through the net and is strained. The ma- 
terial was transferred from the plankton bucket to vials 
and preserved in alcohol. In the subsequent enumeration 
the volume of the catch and preservative was reduced to 
10 cc. ; after shaking thoroughly 2 cc. were removed with 
a piston pipette and the Crustacea and rotifers contained 
therein were counted. The number thus obtained multiplied 
by 5 gives the total number of the various organisms in the 
catch. When only a few individuals of the larger Crustacea 
were present the total was ascertained by direct count. 

The Protozoa and algae were enumerated by placing a 
cubic centimeter of the material in a Sedgwick-Rafter cell 
and then counting the various forms in the usual manner 
with a compound microscope. 

The dry weight and organic matter of the net plankton 
were also obtained. For these determinations a net haul 
was made from surface to bottom (0-32 m.). This catch 
was concentrated on a small piece of bolting cloth ; the ma- 
terial was then carefully removed from the cloth with a 
knife blade and transferred to a small platinum crucible. 
Considerable care is necessary at this stage to prevent loss 
of material. A drop or two of chloroform kills the organ- 
isms and prevents putrefaction while the material is dry- 
ing. The air dried material is then placed in a drying oven 
at 60° for 24 hours and then in a desiccator for 24 hours. 
The dry weight of the catch is obtained by means of a sensi- 
tive assayer's balance. The material is then ignited in an 
electric furnace until the ash appears white, after which 
the weight of the ash is ascertained. 



46 IOWA STUDIES IN NATURAL HISTORY 

Samples of water for a study of the nannoplankton were 
obtained from the various depths by means of a water 
bottle. These minute organisms were removed from the 
water with an electric centrifuge which has a speed of 
3,600 revolutions per minute. The sedimentation was con- 
tinued for about six minutes and the material from the 
bottom of the tube with one cubic centimeter of water was 
transferred to a Sedgwick-Rafter counting cell and the var- 
ious organisms were enumerated. These organisms should 
be counted in the living state since experiments have shown 
that some of them are destroyed by the various preserving 
agents. It is necessary, therefore, to count this material 
as soon as possible after securing the samples. 

It has been found practical to obtain the dry weight and 
organic matter in the nannoplankton also. A sufficient 
amount for this purpose is usually obtained from 90 cc. to 
120 cc. of water. With the standard centrifuge 30 cc. of 
water are centrifuged at each run and the material from 
three or four runs is concentrated in one tube from which 
it can be removed after a final centrif uging with one cubic 
centimeter of water and transferred to a small platinum 
crucible. A drop of chloroform is added and the water is 
allowed to evaporate. Beyond this point the procedure is 
the same as that described above for the net plankton. A 
certain amount of organic matter is dissolved in the water 
and this is not removed with the centrifuge ; it is necessary, 
therefore, to run a blank for this by determining the amount 
of loss on ignition for one cubic centimeter of centrifuged 
water. 

THE NET PLANKTON 

In order to ascertain the vertical distribution of the var- 
ious planktonts, catches were made with the closing net 
from each 5 m. stratum of the lake. The organisms in the 
different strata have been enumerated and the results of 
these enumerations are shown in table 23. The figures 
given in this table indicate the number of individuals or 
colonies per cubic meter of water. 

Phytoplankton. As might be expected the phytoplankton 
was confined chiefly to the upper 10 m., or the epilimnion, 



A LIMNOLOGICAL RECONNAISSANCE 47 

since the supply of light upon which it is dependent for 
carrying on photosynthesis is most favorable in this region. 

Only four forms of green and blue-green algae were found 
in the material, namely, Anabaena, Gloiotrichia, Micro- 
cystis, and Staurastrum. They were present in relatively 
small numbers so that these forms constituted a relatively 
small portion of the total net plankton. 

Four genera of diatoms were present with Stephanodiscus 
as the most abundant; the maximum number of this form 
was found in the 5 m.-lO m. stratum. 

Ceratium was the most abundant protozoan and it ap- 
peared only in relatively small numbers. A few specimens 
of Dinobryon and a heliozoan were found in the m.-5 m. 
stratum while Vorticella was noted in the 5 m.-lO m. 
stratum. 

The catches contained only a small number of rotifers and 
they were confined principally to the epilimnion. They were 
uniformly distributed in this stratum. 

The copepods were relatively the most abundant forms 
and, with the exception of Canthocamptus, they were fairly 
uniform in their distribution from surface to bottom. As 
a whole they furnished the greater part of the material 
obtained in each catch. Diaptomus was more abundant 
than Cyclops and furnished the major portion of the cope- 
pod material. Two species of Diaptomus were present, 
namely, D. clavipes and D. siciloides. 

Adults of D. clavipes constituted about 4% of the total 
number of Diaptomi, but the immature individuals of this 
species composed about two-thirds of the total. These im- 
mature specimens contained a rather large supply of re- 
serve food in the form of oil globules and these gave a yel- 
lowish tint to the whole plankton catch. 

Cyclops was most abundant in the upper 10 m. and below 
25 m., with very few individuals between these two depths. 
The copepod nauplii also showed a similar vertical distri- 
bution; they were much more numerous above 10 m. and 
below 25 m. than in the intermediate strata. 

The Cladocera were represented by specimens of Bosmina, 
Diaphanosoma and three species of Daphnia. A few indi- 



48 IOWA STUDIES IN NATURAL HISTORY 

viduals of Bosmina were found in the 5 m.-lO m. stratum 
while a somewhat larger number of Diaphanosoma was 
noted in the upper 10 m. Of the three species of Daphnia 
the most abundant was D. retrocurva which reached 17,000 
individuals per cubic meter in the upper 5 m. Only about 
a quarter of these were adults. About a third as many were 
found in the 5 m.-lO m. stratum and the number was rela- 
tively small in the deeper strata. This corresponds to the 
usual distribution of this form, which is confined chiefly to 
the epilimnion. Daphnia pulex prefers the cool water of 
the hypolimnion and it was most abundant in that stratum 
of West Okoboji lake. The maximum number was found 
in the 25 m.-30 m. catch. A few specimens of Daphnia 
longispina var. hyalina were noted in two catches, namely, 
those from the 10 m.-15 m. and the 80 m.-32 m. strata. This 
form is usually distributed throughout the entire depth of 
a lake, but in this instance it appeared only in the meso- 
limnion and in the lower part of the hypolimnion. 

The catch which covered the entire depth of the lake 
(0-32 m.) yielded 211.7 mg. of dry net plankton per cubic 
meter of water, of which 91.3% (193.2 mg.) was organic 
matter. 

The average weight of the individuals belonging to the 
more abundant forms of crttstacea was ascertained. For 
this purpose specimens were sorted out under a dissecting 
microscope and these were transferred to small platinum 
dishes. They were then dried, weighed, and ignited as 
described above. The results are given in table 24. 

Six different forms of Crustacea were weighed. Immature 
individuals of Diaptomus clavipes were substantially the 
same in size as the adults of Diaptomits siciloides so that it 
was impossible to separate the two and obtain weights of 
each. The adults of D. clavipes gave a larger dry weight 
and also a larger amount of organic matter for each indi- 
vidual than any of the other Crustacea. The average was 
almost three times as large as that for immature D. clavipes 
and adult D. siciloides and about 40% larger than Daphnia 
pulex and Daphnia longispina var. hyalina. Cyclops aver- 
aged somewhat larger than the immature D. clavipes and 



A LIMNOLOGICAL RECONNAISSANCE 



49 



adult D. siciloides and had a much higher percentage of ash. 
Immediately following the catch which was used to de- 
termine the weight of the total net plankton a second haul 
from surface to bottom was made and the material was 
preserved for purposes of enumeration. A computation 
based on the results of this enumeration and on the average 
weights of the different Crustacea indicates that these six 
forms of Crustacea furnished about 69% of the dry organic 
matter in the total net plankton, of which about 56% was 
derived from the two species of Diaptomns. 

TABLE 23 — Results of the enumerations of the net plankton catches 
from West Okoboji lake, August 1, 1919. The figures 
indicate the number of individuals per cubic meter of 
water for the different strata. 
The following abbreviations have been used: 
Cladocera — B=Bosmina, D.h.=Daphnia longispina var. hyalina, 
D.p.=Daphnia pulex, D.r.=Daphnia retrocurva, T)i=Diaphanosoma; 
Copepoda — Ca.=Canthocamptus, C=Cyclops, D=Diaptomus, N — nau- 
plii; Rotifera — A. c.=Anuraea cochlearis, C=Conochilus, F=Poly- 
artkra; Protozoa — C=Ceratium, D=Dinobryon, H=Heliozoan, 
V=Vorticella; green and blue-green algae — An=Anabaena, G=Gloio- 
trachia, M=Mierocystis, S=Staurastirum; diatoms — A=Asterionella, 
F—Fragilaria, M=Melosira, S=Stephanodiscus. 



Depth, 
meters 


Cladocera 


Copepoda 


Rotifera 


Protozoa 


Green and 

blue-green 

algae 


Diatoms 


0-5 


D.r. 
Di 


17,000 
650 


c 

D 

N 


6,300 

11,600 
10,700 


A.c. 

C 

P 


390 
130 
390 


c 

D 
H 


31,200 
7,800 
7,800 


Anl24,800 
G 11,000 
M 46,800 


A 

F 
M 

S 


23,400 

15,600 

15,600 

140,400 


5-10 


B 

D.p. 
D.r. 
Di 


130 

130 

6,000 

780 


Ca 

C 

D 

N 


390 

4,600 

4,700 

16,500 


A.c. 

C 

P 


260 
130 
650 


C 
V 


15,600 
260 


An 31,200 
G 2,000 
M 70,200 
S 7,800 


F 

S 


23,400 
156,000 


10-15 


D.h. 
D.p. 
D.r. 


130 
650 
520 


C 
D 

N 


650 

10,OOC 

4,30C 


C 130 

> 




An 7,800 
M 7,800 


F 

S 


7,800 
31,200 


15-20 


D.r. 


130 


C 
D 

N 


260 
9,000 
1,170 


P 


130 




M 23,400 


s 


23,400 


20-25 


D.p. 
D.r. 


910 
130 


C 
D 

N 


260 

8,500 
1,170 






An 7,800 


s 


7,800 


25-30 


D.p. 
D.r. 


1,700 
390 


C 
D 

N 


1,600 

6,500 

13,700 




C 


7,800 


M 7,800 


s 


7,800 


30-32 


D.h. 
D.p. 


300 
600 


C 
D 

N 


4,000 
10,000 
10,00C 


A.c. 


300 




An 3,100 


s 


3,100 



50 



IOWA STUDIES IN NATURAL HISTORY 



TABLE 24 — The dry weight, organic matter, and ash of the worms 
and various Crustacea are shown in this table. 





Number 
weighed 


Dry 

weight 
inmg. 


Ash 


One individual 


Remarks 


Mg. 


Per 
cent. 


Dry 

weight 
inmg. 


Organic 
matter 
inmg. 


Diaptomus 
clavipes 


70 


1.61 


0.115 


7.14 


0.023 


0.0213 


Adult 


Diaptomus 
siciloides 
and imma- 
ture D. 
clavipes 


400 


3.22 


0.09 


3.00 


0.00805 


0.00782 




Cyclops 


95 


0.905 


0.09 


10.00 


0.00953 


0.00858 


Mainly adult 


Daphnia 
pulex 


100 


1.97 


0.39 


20.00 


0.0197 


0.0158 


Mainly adult 


Daphnia 
longispina 
var.hyalina 


75 


1.395 


0.265 


19.00 


0.0186 


0.01506 


Adult 


Daphnia 
retrocurva 


250 

1 


1.43 


0.26 


18.18 


0.00572 


0.00468 


Mainly young 


Oligochaeta 


180 1 34.79 


1.67 


4.80 


0.19328 


0.184 


Mixed sizes 



THE NANNOPLANKTON 

A relatively small number of forms was present in the 
nannoplankton material, but two were found in consider- 
able numbers. (See Table 25) . The ciliated Protozoa were 
represented by Halteria and Vorticella; a comparatively 
small number of each was found in the epilimnion while 
the former was also found in the material from a depth of 
33 m. Some specimens of Cryptomonas were noted in the 
samples from 10 m. and 30 m. as well as Pandorina at 10 m. 
Minute flagellated monads were distributed throughout the 
depth of the lake, but they were much more abundant in 
the epilimnion than in the other strata. 

Only two forms of algae were noted, namely, Aphano- 
capsa and Oocystis. A small number of the latter was 
found in the surface sample. The Aphanocapsa consisted 
of small colonies of minute cells, 25 to 100 in number, em- 
bedded in a gelatinous matrix. It seems to have a wide dis- 
tribution since it appears in the nannoplankton of all of the 
lakes of this country on which observations have been made. 
It was found at all depths, but was most abundant in the 



A LIMNOLOGICAL RECONNAISSANCE 



51 



upper strata. Attention may be called to the fact here 
that this form has also been found in the lower water of 
much deeper lakes, such, for example, as Seneca lake, New 
York, which has a maximum depth of 188.4 m. (618 ft.). 

TABLE 25 — Analysis of the nannoplankton. The figures given in 
this table indicate the number of individuals per liter of 
water. 
The following abbreviations have been used: 
Protozoa, C=Cry'ptomonas, H=Halteria, M=Monas, F=Pandorina, 
V=:Vorticella; Algae, A=Aphanocapsa, 0=Oocystis. 



Depth, 
meters 


Protozoa 


Algae 





H 5,200 
M 156,200 
V 5,200 


A 
O 


859,100 
5,200 


10 


C 10,400 
H 5,200 
M 234,300 
P 5,200 


A 


781,000 


20 


M 10,400 


A 


781,000 


30 


C 5,200 
M 5,200 


A 


390,500 


33 


H 5,200 
M 15,600 


A 


390,500 



For obtaining the weight of the nannoplankton a com- 
posite sample was prepared by mixing equal volumes of 
water from each 5 m. level of the lake. The dry organic 
matter in the material obtained from this sample amounted 
to 333.0 mg. per cubic meter of water. This amount plus 
that in the net plankton (193.2 mg.) gives 526.2 mg. per 
cubic meter of water for the total plankton; approximately 
63% of this total is derived from the nannoplankton and 
37% from the net plankton. This sum multiplied by the 
maximum depth of the lake, that is, 40.2, gives 21,153 mg., 
or 21.1 grams, per square meter of surface in the deepest 
water. 

Assuming that this plankton material was uniformly dis- 
tributed over the whole lake, then the average per square 
meter of surface for the entire lake may be obtained by 
multiplying the sum of the net plankton and nannoplankton 
by the mean depth, namely, 12.3 (See table 2). This gives 
6,472 mg., or about 6.5 grams per square meter of surface. 
Again assuming a uniform distribution, the dry organic 



52 IOWA STUDIES IN NATURAL HISTORY 

matter in the total plankton of the entire lake may be cal- 
culated from the volume given in table 2; this amounts to 
98,520 kg. which is equivalent to about 108 tons. Expressed 
in terms of a unit area this is 64.5 kg. per hectare, or 57.5 
pounds per acre. In the living state this material would 
weigh about ten times as much, since various experiments 
have shown that about 90% of the live weight of these 
organisms consists of water. 

This represents a small amount of organic matter per 
unit of area but these figures indicate only the standing 
crop at this particular time of the year. Both production 
and destruction of this material are taking place at all 
seasons of the year and the quantity of organic matter 
found at a particular time is the resultant of these two 
processes. Some of the forms reproduce much more rapidly 
than others and also reproduction is much more vigorous at 
certain seasons so that there is considerable variation in the 
quantity of this material at different seasons. The more 
minute organisms serve as food for the larger ones, such as 
the Crustacea, and these in turn are eaten by the fish and 
other aquatic organisms; some forms of the Crustacea, in 
fact, prey upon others. Thus the whole problem is a very 
complex one so that it would be extremely difficult to ascer- 
tain, even roughly, the total annual production of plankton. 

A comparison with results that have been obtained on 
lake Mendota will serve to show the relative plankton pro- 
ductiveness of the two lakes. Table 26 gives the amount of 
net and nannoplankton found in this lake during the last 
week in July and the first week in August both in 1915 and 
1916. The figures represent the average amount of organic 
matter for these two weeks in both years and they indicate 
the quantity in milligrams per cubic meter of water. It 
will be noted that the organic matter in the net plankton of 
lake Mendota in 1915 was substantially the same as that of 
West Okoboji in 1919, but that it was very much smaller 
in the former in 1916. On the other hand the nannoplank- 
ton of lake Mendota was about five times as great in both 
years as that of West Okoboji lake. The last column of the 
table shows that the total plankton was more than three 



A LIMNOLOGICAL RECONNAISSANCE 53 

times as great in the former lake as in the latter. On the 
assumption that the amounts in this table represent a fair 
average per cubic meter of water for the whole lake, a com- 
putation based on these figures gives an average of 222.2 kg. 
per hectare of surface for lake Mendota in 1915, or 198 
pounds per acre. The quantity in 1916 was about 6% less 
than this amount. This is nearly four times as much as 
was found in West Okoboji lake in 1919. The quantity of 
total plankton has been determined for only a few of the 
Wisconsin lakes, but, of those on which determinations have 
been made so far, only one falls as low as West Okoboji 
lake. The total plankton of Devil's lake, Wisconsin, on 
August 27, 1919, amounted to 500 mg. of dry organic mat- 
ter per cubic meter of water, or about 2% less than that of 
West Okoboji lake. This result for Devil's lake means a 
much smaller amount per unit of area since it is a much 
shallower lake; that is, it represents only 44.5 kg. per hec- 
tare, or approximately 40 pounds per acre. On the basis 
of these results both of these lakes must be classed as 
plankton poor. 

TABLE 26 — This table gives the number of milligrams of organic 
matter per cubic meter of water in the net plankton and 
in the nannoplankton of lake Mendota and of Okoboji lake 
in the years indicated. The quantities given for the for- 
mer lake are the averages of the last week in July and 
the first week in August each year, while those for the 
latter lake were obtained in observations made on Julv 
31, 1919. * 



Lake 



| Mendota 



Mendota 



West Okoboji 



Year I Net 



1915 I 195.7 



1916 I 96.5 



1919 I 193.2 



Nannoplankton | Total 1 



1,634.3 | 1,830.0 



1,630.6 [ 1,727.1 



333.0 [ 526.2 



BOTTOM FAUNA 

Some samples of mud were obtained from the bottom in 
the deeper water by means of an Ekman dredge. This 
material was sifted through a fine meshed net for the pur- 
pose of ascertaining the number and variety of the macro- 
scopic fauna of the bottom. The time that could be devoted 
to this work was very brief so that hauls were made at only 
two different depths, namely, 21 m. and 33 m. The results 
obtained from the samples are shown in table 27 ; they give 



54 IOWA STUDIES IN NATURAL HISTORY 

only a very fragmentary idea of the bottom fauna since 
they are limited to two depths and since they were made at 
a time when the insect larvae are at their minimum in va- 
riety and number. A proper study of the bottom popula- 
tion would require hundreds of observations; these should 
cover all depths, from the shoreline to the deepest water in 
various parts of the lake, as well as all seasons of the year. 
Such a study would involve the expenditure of much time 
and labor but the results would undoubtedly amply justify 
the undertaking. 

Only three groups of bottom dwellers were found in any 
abundance. The Chironomus larva apparently belongs to 
the tentans group and all of the specimens were either full 
grown or nearly so, varying in length from 21 mm. to 25 
mm. Protenthes was not noted at 21 m. but a few were 
found at 33 m. ; these specimens were substantially full 
grown larvae also. The Oligochaeta included representa- 
tives of Limnodrilus and Tubifex. In addition to these some 
ostracods and nematodes were noted at both depths. 

The chironomids were more abundant at 21 m. than at 
33 m. while the reverse was true of the Oligochaeta. 

The weight of the forms shown in table 27 were deter- 
mined and the amount of organic matter per square meter 
of bottom is indicated in the table in grams. The Oligo- 
chaeta varied greatly in size so that it was necessary to 
pick out and weigh all of the specimens in a single haul of 
the dredge in order to get an average. While the total 
number of individuals was much larger at 33 m. than at 
21 m., the reverse was true on the basis of the amount of 
dry organic material ; the larger number of Oligochaeta at 
the former depth did not compensate for the larger bulk of 
the chironomids at the latter depth. 

Stated in larger units this bottom fauna yielded 109.6 kg. 
of dry organic matter per hectare, or 97.6 pounds per acre, 
at 21 m., and 65.1 kg. per hectare, or 58.0 pounds per acre, 
at 33 m. The latter figure is substantially the same as the 
average yield of the total plankton. (See p. 51). These 
figures, like those for the total plankton, do not represent 
the annual production, but they indicate the number of 



A LIMNOLOGICAL RECONNAISSANCE 



55 



bottom dwellers present at a particular time and the amount 
of organic matter in them. The annual production involves 
the yearly turn-over in the bottom population, and this ques- 
tion includes such problems as the number of broods of 
insect larvae annually, the rate of reproduction of the Oli- 
gochaeta, and the extent of the depletion of this entire 
population each year by being consumed as food and by 
other causes. 



TABLE 27 — Observations on the bottom fauna of Okoboji lake, July 
30 and 31, 1919. The first column for each depth shows 
the number of individuals per square meter of bottom 
and the second column gives the number of grams of dry 
organic matter per square meter. 



1 


Twenty-one Meters 1 


Thirty-three Meters 


1 


Number 


Organic Matter 1 


Number 1 Organic Matter 


| Chironomus 


1,110 


9.49 | 


355 | 3.03 


| Protenthes 




| 266 | 0.88 


| Oligochaeta 


7,992 


1.47 | 


14,120 | 2.60 


1 Total 




10.96 | 


| 6.51 



56 IOWA STUDIES IN NATURAL HISTORY 

PAPERS CITED 

Birge, '10. An unregarded factor in lake temperatures. E. A. Birge. 
Trans. Wis. Acad. Sciences, Arts, and Letters, Vol. XVI. 
pp. 989-1004; 2 pi. Madison, 1910. 

Birge, '15. The heat budgets of American and European lakes. E. A. 
Birge. Trans. Wis. Acad. Sciences, Arts, and Letters, Vol. 
XVIII, pp. 166-213; 3 figs. Madison, 1915. 

Birge, '16. The work of the wind in warming a lake. E. A. Birge. 
Trans. Wis. Acad. Sciences, Arts, and Letters, Vol. XVIII, 
pp. 341-391; 10 pi. Madison, 1916. 

Birge and Juday, '11. The inland lakes of Wisconsin; the dissolved 
gases of the water. E. A. Birge and Chancey Juday. Bull. 
Wis. Geol. Survey, No. XXII, pp. i-xx, 1-259; 142 figs. 
Madison, 1911. 

Ford, '13. A topographical survey of the Spirit and Okoboji lakes 
region. H. C. Ford. Bull. Iowa State Coll. Vol. XI, No. 6, 
pp. 1-38; 21 cuts, 4 maps. Ames, 1913. 

Iowa, '16. Report of the state highway commission on the Iowa lakes 
and lake beds. 1 vol. text, pp. 1-250, 109 figs; 1 vol. of 72 
maps. Published by State. Des Moines, 1916. 

Juday, '14. The inland lakes of Wisconsin: hydrography and morpho- 
metry, Chancey Juday. Bull. Wis. Geol. and Nat. Hist. 
Survey, No. XXVII, pp. i-xv, 1-137; 37 maps. Madison, 
1914. 

Tilton, '16. Records of oscillations in lake level and records of lake 
temperatures and of meteorology secured at the Macbride 
Lakeside Laboratory, Lake Okoboji, Iowa, July, 1915. John 
L. Tilton. Proc. Iowa Acad. Science, Vol. XXIII, 1916, pp. 
91-102; 4 figs. 

Tilton, '11. Second record of oscillations in lake level with record of 
lake temperatures and meteorology secured at the Mac- 
bride Lakeside Laboratory, Lake Okoboji, Iowa, July, 1916. 
John L. Tilton. Proc. Iowa Acad. Science, Vol. XXIV, 1917, 
pp. 34-41; 4 figs. 



Oversized 
Foldout 



F1KKT SERIES No. 38 DECEMBER 1, 1920 



UNIVERSITY OF IOWA 
STUDIES 



STUDIES IN NATURAL HISTORY 



Volume IX Number 2 



NESTING HABITS OF THE HERMIT THRUSH 
IN NORTHERN MICHIGAN 

by 
DAYTON STONEB 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 



Issued semi-monthly throughout the year. Entered at the post office at Iowa City, 
Iowa, as second class matter. Acceptance for mailing at special rates of postage 
provided for in section 1103, Act of October 3, 1917, authorized on July 3, 1918. 



UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 

Professor CHARLES CLEVELAND NUTTING, M. A., Editor 



Continuation of Bulletin from the Laboratories of Natural History 
of the State University of Iowa 

Volume IX Number 2 



NESTING HABITS OF THE HERMIT THRUSH 
IN NORTHERN MICHIGAN 

by 
DAYTON STONEE, Ph. D. 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 



THE NESTING HABITS OF THE HERMIT THRUSH 

HylocicMa guttata pallasi (Cab.) IN NORTHERN 

MICHIGAN 

By Dayton Stoner 



INTRODUCTION 
The data which serve as a basis for this paper were obtained 
at the University of Michigan Biological Station on Douglas 
Lake while the writer was a member of the station staff. Ob- 
servations were made during the latter part of July and the 
first few days of August, 1919. In addition to the writer's own 
observations and notes, the assistance of the members of the 
class in ornithology was requisitioned. Several other members 
of the camp also very kindly rendered service in various ways. 
To all of these obligation is gratefully acknowledged. 

The Douglas Lake region lies in the extreme northern part 
of the southern peninsula of Michigan about seventeen miWs 
from Lake Huron on the east, the Straits of Mackinac on the 
north and Lake Michigan on the west. The soil is exceedingly 
sandy. The topography is strongly rolling and was formerly 
covered by hardwoods and conifers but large areas have been 
cut over and burned over so that little of the original forest 
now remains. There are numerous lakes in the region of Doug- 
las Lake which is about two hundred feet above sea level and 
some two and one-half miles wide by four miles long ; its great- 
est depth is about ninety feet. Its shores are variable as to 
height and slope but are everywhere wooded. 

Near the Biological Station camp on the east side of the lake 
where the following observations were made, the shores are low 
and gradually receding with a long, clean, sandy beach. Con- 
ifers, maples, birches and aspens, mostly second growth, are 
found though not in abundance. Blueberry bushes and brake 
fern make up the characteristic smaller vegetation. 

Naturally such situations afford unusual inducements for 
nesting birds of various species. Here song sparrows, oven- 
birds, slate-colored juncos, towhees, red-eyed vireos, cedar wax- 



es) 



4 IOWA STUDIES IN NATURAL HISTORY 

wings and many others find suitable sites for homes and the 
rearing of their young. The hermit thrush is one of the com- 
moner summer birds of the region and several nests were dis- 
covered during the course of the eight weeks' summer session 
beginning June 30. 

Although numerous papers have been written concerning 
the nesting behavior of the hermit thush, the observations made 
by Norman McClintock 1 in the Huron Mountains forty miles 
northwest of Marquette, Michigan, are the most complete and 
detailed of any that the writer has seen. However, the obser- 
vations herein recorded are, in some respects, somwhat at var- 
iance with those of McClintock and additional data are also 
included in this paper. 

The particular nest here discussed was accidentally discov- 
ered on July 5 hy one of the members of the ornithology class 
but it was not under more than casual observation until July 
25 when a blind was first put into position for the observers. 
The nest itself was built on the ground in a partly shaded area 
about twenty yards from the lake shore and the same distance 
from the mess tent which was visited three times a day by 
thirty-nine people. It was partially hidden among the blue- 
berry bushes and brake fern and was composed almost entirely 
of pine needles with a few dead twigs at the top and on the out- 
side for support. 

The observation blind of faded, olive-green canvas was erected 
on two T-poles. It was about forty inches in height by twenty 
inches in width by thirty-eight inches in length and was placed 
thirty inches from the nest. Observation of the birds and nest 
was made possible through a slit about six inches long in the 
canvas and through a round hole two inches in diameter. En- 
trance to the blind was gained on the side away from the nest 
and it was left in position continuously from the time it was 
erected until August 8, when the birds left their home. During 
the process of setting up the blind the female hermit thrush flew 
away thus exposing the five eggs; as soon as the canvas was in 
place the observer left. The next morning the writer visited the 
blind but remained only long enough to make sure that the 
female was incubating. During the following night a heavy 



1 McClintock. Norman. A Hermit Thrush Study, Auk, XXVII, 1910, 409-418. 



NESTING HABITS OF HERMIT THRUSH 5 

wind disarranged the blind and while it was being repaired 
and readjusted on the morning of the 27th the female remained 
on the nest apparently little excited by the procedure. 

The female remained constantly on duty until 6:00 p. m. on 
July 30 when she was flushed, and four nestlings, not more than 
twenty-four hours old, were disclosed. The fifth egg proved to 
be addled but remained in the nest during the entire subsequent 
brooding period. 

BROODING 

So far as our observations are concerned all the brooding was 
done by the female. When the young were first hatched the fe- 
male seldom left them for long intervals, but toward the close 
of our period of observation the time spent by the adult on or 
at the nest was much reduced. However, it seemed that both 
parents were near and ready to swoop down to recover a voided 
excreta sac. 

During the first part of the brooding the female would often 
rise slightly in the nest and look down at the youngsters 
solicitously. This occurred oftener on warm days and was 
probably for the purpose of giving the nestlings air. Some- 
times when in this attitude the female would peck none too 
gently the heads and eyelids of the nestlings. 

At times, while brooding, the female reached down into the 
bottom of the nest with her bill and shaking her head rapidly 
up and down or from side to side appeared to be loosening the 
packed-down materials. As the young grew larger the female 
did not sit on them but hovered over them, clinging with her 
feet to the sides of the nest. During the last two days of our 
observations she remained on its edge seldom attempting to 
brood the nestlings. In brooding the female always rested with 
her head toward the blind. 

The male was much more nervous and noisy in his actions 
than the female. Although he took no part in the brooding he 
was particularly active in securing food for the young birds. 
Usually he left almost immediately after delivering the food, 
often touching the blind with the tips of his wings in his hasty 
departure. 



6 IOWA STUDIES IN NATURAL HISTORY 

FOOD AND FEEDING HABITS 

Perhaps the most interesting part of the entire study was 
concerned with the food and feeding habits. Probably the 
larger share of all the food fed to the young was gleaned within 
a few yards of the nest. 

On the writer's appearance near the blind at 7:30 a. m. of 
July 31 the male from a near by tree gave a sharp call, and 
three minutes later a rustling in the leaves on the side of the 
nest away from the blind betrayed his approach. The brood- 
ing female turned her head upward and backward and accepted 
a bit of food from him. It was impossible to identify this food 
for the male inserted his bill well down into the wide open 
mouth of the female. This was the first and, with two excep- 
tions, the only time that one adult bird was observed to feed 
the other. 

The following tables, chronologically arranged, will serve to 
show the principal details regarding the feeding of the young 
by the parents as well as to give data on nest sanitation. A 
word of explanation concerning the characters and abbrevia- 
tions employed in the tables may be opportune ac this point. 

Lepid. larva indicates a lepidopterous larva of some kind. 

Acridiid refers to any of the several species of short-horned 
grasshoppers which formed a substantial part of the diet of the 
young. 

Gryllid refers to whatever species of cricket may have been 
served as food. 

Ad. refers to one of the adults, sex undetermined. 

Juv. refers to one of the nestlings. 

t inserted in the "Kind of food" column indicates that the 
food which was brought could not be determined either from 
lack of ability to see it sufficiently or to properly identify it. 

A blank space in any colmn indicates that such part of the 
observation was not made. 

The usual signs 6 (male) and 9 (female) are used freely. 



NESTING HABITS OP HERMIT THRUSH 
Table I— July 31 



Time of 


Kind of Remarks Disposition 


Remarks 


feeding 


food of excreta 




7:49 A. M. 


? 6 feeds 2 juvs. 




8:04 A. M. 


Lepid. larva $ feeds 1 juv. None 




8:09 A. M. 


? 6 gives food to Deposited in 


Picked up and swal- 




brooding $ nest 


lowed by $ 




who feeds 1 






-— •^-■-^ juv. 




4:10 P. M. 


Lepid. lar- $ divides larva None 
val%"long between 2 
juvs. 




4:12 P. M. 


Acridiid $ feeds 1 juv. By 2 juvs. 


Received directly; 
swallowed by $ 


4:35 P. M. 


? 6 feeds 1 juv. By 1 juv. 


Received directly; 
swallowed by 6 


4:50 P. M. 


Larva part- $ feeds 2 juvs. By 1 juv. 


Received directly; 




ly crushed 


swallowed by $ 


4:52 p. M. 


? 6 feeds 1 juv. None 




4:58 P. m. 


Cutworm $ feeds 3 juvs. None 




5:08 P. M. 


3 Acridiids 6 feeds 3 juvs. None 




5:17 P. M. 


? 6 feeds 1 juv. By 1 juv. 




5:18 P. M. 


? $ feeds 1 juv. By 1 juv. 





General Remarks on Table I 

Observations were made between the hours of 7 :00 and 9 :30 
A. m. and 4:00 and 5:22 p. m., a total period of four houis and 
fifty-two minutes, during which the young were fed twelve 
times. 

At 8 :39 a. m. the brooding female partly arose from the nest 
and picked up an excreta sac which had been deposited by one 
of the young. While in most cases the parent was on the look- 
out at the time the excreta sac was voided, this was not invar- 
iably true. After feeding a nestling the parent bird sometimes 
waited for from several seconds to a minute at the edge j£ the 
nest to see if the excreta sac would be voided. Whenever it was 
expelled the adult ordinarily immediately swallowed it before 
it fell. As near as could be ascertained this excreta sac was 
swallowed by the parent at the nest until about noon on August 
3, when the adult was first seen to carry the sac away. 

The excreta sac was not always voided by a nestling immedi- 
ately after it had been fed as is indicated in numerous instances 
in the tables. Usually when the young voided the excrement 
both the head and the vent were raised, although on some oc- 
casions the head was lowered in this act. The excrement ap- 



IOWA STUDIES IN NATURAL HISTORY 



peared to be contained within this gelatinous sac during the 
entire time that the young were in the nest. 







TABLE II- 


-August 1 




Time of 
feeding 


Kind of 
food 


Remarks 


Disposition 
of excreta 


Remarks 


9:06 A. M. 


2 Lepid. 
larvae 


9 feeds both to By same 
1 juv. juv. 


Act occurred imme- 
diately after being 
fed. Swallowed by 
$ 
Swallowed by 6 
Swallowed by $ 
Swallowed by 6 ; 
leaves at once 


9:26 A. M. 
9:35 A. M. 
9:46 A. M. 

9:52 A. M. 


7 

Acridiids 
? 


6 feeds 2 juvs. 
$ feeds 1 juv. 
6 feeds 4 juvs. 

$ feeds 2 juvs. 


By 1 juv. 
By 1 juv. 
By 1 juv. 

By 1 juv. 


9:58 A. M. 

10:14 A. M. 

11:14 A. M. 
11:15 A. M. 

11:16 A. M. 


3 Acridiid 
nymphs 

Lepid. lar- 
va 2" long 

Acridiid 

Acridiid 

Hairy Le- 


$ feeds 2 juvs. 

6 feeds 1 juv. 

9 feeds 1 juv. 
6 feeds 1 juv. 

9 feeds 1 juv. 


By 1 juv. 

By 1 juv. 

By 1 juv. 
By 2 juvs. 


Swallowed by 6 ; 
leaves at once 

Received and swal- 
lowed by 6 



pid. larva 

General Remarks on Table II 

Observations were made on this date only between the hours 
of 9 :00 and 11 :18 a. m. during which period the young were fed 
ten times. 

From what the writer saw on this and subsequent occasions 
he is led to the belief that the parent birds, both of whom fed 
the young and removed the excreta, exercised very little choice 
or discrimination in selecting a certain nestling to receive what- 
ever food was brought. One nestling might receive food two 
or three times in succession, while another might have to go 
hungry for as many visits. 

During the first days of feeding the nestlings both parents 
announced their arrival in the vicinity by a low trill or chirp. 
Invariably upon hearing this note the mouths of all the young- 
sters were opened widely. The female ordinarily alighted 
about five feet from the nest, surveyed the situation for an in- 
stant, then ran toward the waiting young. The male usually 
arrived at or very near the nest with a considerable flutter of 
wings. 

The hairy lepidopterous larva fed at 11:36 was an unusual 



NESTING HABITS OF HERMIT THRUSH 9 

morsel for the nestlings; during the entire time that the birds 
were under observation a hairy caterpillar was not again 
offered. 

The larva which was brought to the young by the male at 
10 :14 was offered to one nestling who made a vigorous but un- 
successful attempt to swallow it. The parent seeing the dilem- 
ma of the youngster took it from his throat and ran the larva 
slowly and carefully through his own mandibles, in this way 
crushing it; he then fed it to a different nestling who also at- 
tempted the impossible. After removing the larva from his 
throat and crushing it still further and in the same manner as 
before the parent offered the now sadly bedraggled larva to the 
original recipient who succeeded in his efforts at swallowing it. 
The entire performance lasted about three minutes. 

As again illustrating the fact that the young void the excre- 
ment at other times than immediately after being fed the fol- 
lowing excerpt from the writer's notes of this date may be 
quoted: "At 9:19, after the female had been brooding for 
several minutes, she arose in the nest and took a bit of excre- 
ment from one of the nestlings. ' ' 

The hour between 10 :14 and 11 :14 when the young were not 
fed was occupied partly by the female in brooding although she 
did not return to the nest until 10 :28 at which time she brought 
no food. 



10 



IOWA STUDIES IN NATURAL HISTORY 



TABLE III— August 2 



Time of 


Kind of 


Remarks 


Disposition Remarks 


feeding 


food 




of excreta 




7:06 A. M. 


9 


$ feeds 1 juv. 






7:18 A. M. 


Larva 


6 feeds both 9 
and juv. 






7:25 A. M. 


? 


6 feeds both 9 
and juv. 






8:08 A. M. 


Insect 


9 feeds 1 juv. 






8:09 A. M. 


Larva 


6 feeds 1 juv. 






8:21 A. M. 


Larva 


9 feeds 1 juv. 






8:24 A. M. 


Larva 


6 feeds 1 juv. 






8:26 A. M. 


Larva 


9 feeds 1 juv. 






8:42 A. M. 


Larva 


9 feeds 1 juv. 






8:50 A. M. 


Larva 


6 feeds 1 juv. 






9:02 A. M. 


Larva 


6 feeds 2 juvs. 






9:30 A M.. 


? 


9 feeds 2 juvs. 






10:01 A. M. 


Insect 


6 feeds 3 juvs. 


By 1 juv. 




10:31 A. M. 


Insect 


6 feeds 2 juvs. 


By 1 juv. 




10:40 A. M. 


Gryllid & 
Acridiid 


6 feeds 1 juv. 


By 1 juv. 




10:41 A. M. 


? 


9 feeds 1 juv. 


By 1 juv. 


Swallowed by 9 


11:12 A. M. 


Larva 


6 feeds 1 juv. 


By 1 juv. 


Swallowed by 6 


11:27 A. M. 


? 


9 feeds 1 juv. 


By 1 juv. 


Swallowed by 9 


11:34 A. M. 


Acridiid j 


6 feeds 3 juvs. 
9 feeds 2 juvs. 


By 1 juv. 


Swallowed by 9 


11:57 A. M. 


? 


6 feeds 1 juv. 






12:01 P. M. 


Lepid lar- 


9 feeds 1 juv. 






2:03 p. M. 


va 

9 


6 feeds 2 juvs. 


By 2 juvs. 


Swallowed by 6 


2:12 P. M. 


9 


6 feeds 2 juvs. 


By 2 juvs. 


Swallowed by 6 


2:23 P. M. 


Lepid. larva 6 feeds 1 juv. 


None 




2:28 p. M. 


? 


6 feeds 1 juv. 


None 




2:29 P. M. 


? 


6 feeds 3 juvs. 


None 




3:15 P. M. 


Leg of 
Acridiid 


9 feeds 1 juv. 


None 




3:23 P. M. 


Fragment 










of Acridiid 9 feeds 1 juv. 


By 1 juv. 


Swallowed by 9 


3:25 P. M. 


? 


6 feeds 1 juv. 


None 




3:35 P. M. 


9 


9 feeds 1 juv. 


None 




3:46 P. M. 


9 


6 feeds 1 juv. 


By 1 juv. 


Swallowed by 6 


4:21 p. M. 


Lepid. larva $ feeds 1 juv. 


By 1 juv. 


Swallowed by 9 


4:39 p. M. 


? 


& feeds 2 juvs. 


By 1 juv. 


Swallowed by 6 


4:45 P. M. 


Moth' 


9 feeds 2 juvs. 


None 




4:52 p. M. 


Gryllid 


9 feeds 1 juv. 


None 




5:06 P. M. 


Insect 


9 feeds 1 juv. 


None 




5:16 p. M. 


Green Le- 
pid. larva 


9 feeds 1 juv. 


None 





General Remarks on Table III 
On this date observations were made between 9 :00 a. m. and 
12 :01 p. m. and between 2 :00 and 5 :18 p. m. during which period 
thirty-eight feedings were administered. 



NESTING HABITS OF HERMIT THRUSH 11 

The insect fed to the nestling at 8 :08 was secured by the fe- 
male not more than a foot from the nest. She left her brooding 
only long enough to capture the insect and to feed it to the 
nestling then resumed her place on the nest. 

At 11:34 both parents appeared at the nest with food at 
about the same time, an unusual occurrence. 

At 11:52 a. m. and again at 3:02 p. m. one of the nestlings 
defecated without having been fed. The excreta sac was taken 
from the vent of the nestling and swallowed by the brooding 
female on both occasions. 

At 4:50 the female picked and ate blueberries near the nest 
but offered none to the nestlings. At no time during our obser- 
vations were the young offered berries or fruit. 



12 IOWA STUDIES IN NATURAL HISTORY 

TABLE IV— August 3 



Time of 


Kind of 


Remarks Disposition 


Remarks 


feeding 


food 


of excreta 




9:12 A. M. 


? 


6 feeds 2 juvs. 




9:17 A. M. 


? 


9 feeds 2 juvs. By 1 juv. 


Swallowed by 9 


9:35 A. M. 


Lepid. larva 
& 2 Acri- 
diids 


6 feeds 2 juvs. By 1 juv. 


Swallowed by 6 


9:43 A. M. 


2 Gryllids 


6 feeds 2 juvs. None 




9:54 A. M. 


1 Gryllid 


6 feeds 1 juv. None 




9:56 A. M. 


1 Gryllid 


$ feeds 1 juv. By 1 juv. 


S wall awed by 9 


9:57 A. M. 


Spider 


6 feeds 1 juv. None 




10:14 A. M. 


2 Gryllids 


6 feeds 1 juv. By 1 juv. 


Swallowed by 6 


10:15 A. M. 


2 Gryllids 


9 feeds 1 juv. By 2 juvs. 


Swallowed by 9 


10:27 A. M. 


1 Gryllid & 


6 feeds 1 juv. By 1 juv. 


Swallowed by 6 as 




1 Acridiid 




he flew away 


10:42 A. M. 


Lepid. larva 


6 feeds 1 juv. By 1 juv. 


Swallowed by 6 




& Gryllid 


(not the 
one fed) 




10:43 A. M. 


? 


$ feeds 1 juv. None 




10:50 A. M. 


Gryllid 


6 feeds 1 juv. None 




10:54 A. M. 


1 Acridiid 


9 feeds 1 juv. By 1 juv. 


9 flies away with 




& 1 Gryllid 


both insects (not the 
at same ttae one fed) 


excrement in bill 


3:10 P. M. 


Insect 


$ feeds 1 juv. None 




3:28 P. M. 


Insect 


$ feeds 1 juv. 




3:42 p. M. 


3 insects 


$ feeds 4 juvs. 




3:45 P. M. 


Insect 


9 feeds 1 juv. 




3:58 p. M. 


? 


6 feeds 1 juv. None 




4:08 P. M. 


Several 
insects 


6 feeds 2 juvs. 




4:11 p. m. 


Larva 


9 feeds 3 juvs. 


Excreta swallowed 


4:22 p. M. 


1 


6 feeds 2 juv?. 


by 9 


4:30 P. M. 


i 


$ feeds 2 juvs. 
(not the ones 
just fed) 




4:35 P. M. 


9 


6 feeds 1 juv. 




4:52 p. M. 


Insect 


9. feeds 3 juvs. 




4:59 P. M. 


? 


6 feeds 1 juv. 





General Remarks on Table IV 

The observations on this date covered the time between 8 :55 
and 11 :00 a. m. and 3 :05 and 5 -.06 p. m. during which twenty- 
six feedings were administered. 

The male usually announced his arrival by a low trill and 
as soon as the brooding female heard it she left the nest. Al- 
most immediately after feeding the young he flew away again. 
This behavior was fairly constant throughout our observations. 

The foregoing table shows a greater variety of food brought 
to the nestlings than heretofore. 



NESTING HABITS OF HERMIT THRUSH 



13 



At 9:57 both parents were at the nest with food. At 4:58 
the female after having been absent for four minutes returned 
without food. 

Apparently the young defecate only when one of the parent 
birds is at the nest. 



TABLE V— August 4 



Time of 
feeding 



Kind of 
food 



Remarks 



Disposition 
of excreta 



Remarks 



7:25 a.m. ? 9 feeds 4 juvs. By 1 juv. 

7:31 a. M. Lepid. larva $ feeds 4 juvs. 
7:34 A. M. ? 6 feeds 1 juv. 

7:50 A. m. Lepid. larva 6 feeds 2 juvs. By 2 juvs. Swallowed by 6 
8:02 A. M. ? $ feeds 1 juv. 9 picks bit of excrement . from 

bottom of nest and swallows it 



8 : 16 A. M. Lepid. larva 



£:26 A. M. 
8:32 A. M. 

8:40 A. M. 



8:43 A. M. 
8:46 A. M. 



8:50 A. M. 
8:51 a. .M 
^:52 A. M. 
9:07 A. M. 
9:09 A. M. 
9:16 A. 
9:32 A. 
9:42 A. 
9:45 A. 



M. 
M. 
M. 
M. 



10:03 A. M. 
10:06 a. M. 

10:18 A. M. 

10:25 A. M. 

10:48 A. M. 

10:55 A. M. 
3:12 p. M. 



Green lepid. 
larva 

9 



Larva 



Larva 
? 

? 

Green lepid. 
larva 

Insect 
Gryllid 



6 feeds 1 juv. 
(leaves at 
once). 

9 feeds 2 juvs. By 1 juv. 9 flies away with it 
6 feeds 3 juvs. 

(leaves at 

once) 
6 feeds 2 juvs. 

(leaves at 

once) 

9 feeds 3 juvs. 
6 feeds 1 juv. 

(leaves at 

once) 

6 feeds 1 juv. By 1 juv Removed by 6 
$ feeds 2 juvs. 
6 feeds 1 juv. 
6 feeds 3 juvs. 
$ feeds 1 juv. By 1 juv. 
6 feeds 2 juvs. None 
$ feeds 1 juv. By 1 juv. 
$ feeds 3 juvs. 
6 feeds 1 juv. 

(leaves at 

once) 

9 feeds 2 juvs. By 1 juv. 
6 feeds 2 juvs. By 1 juv. 



Swallowed by 9 
Swallowed by 9 



Green lepid. £ feeds 2 juvs. 

larva 
Green lepid. 9 feeds 1 juv. By 1 juv. 

larva 
Green lepid. 9 feeds 1 juv. By 1 juv. 
larva 

° 9 feeds 1 juv. By 1 juv. 

6 feeds 1 juv. 



Swallowed by 9 
6 flies away with ex- 
crement in bill 



9 flies away with ex- 
crement in bill 
Swallowed by 9 

Swallowed by 9 



14 IOWA STUDIES IN NATUKAL HISTOKY 

3:20 P. M. Insect Ad. feeds 3 

juvs. (leaves 

at once) 
3:31 p. m. Insect 6 feeds 1 juv. By same Swallowed by 6 

juv. as fed 
3:34 p. m. ? 2 feeds 1 juv. 

(leaves at 

once) 
3:48 p. m. ? Ad. feeds 1 By 1 juv. Ad. leaves with ex- 

juv. crement in bill 

4:02 p. m. ? 6 feeds 1 juv. By 1 juv. Swallowed by 6 

4:03 p. m. ? 9 feeds 1 juv. 

4:08 p. m. ? 6 feeds 1 juv. By 1 juv. 6 flies away with ex- 

crement in bill 
4:35 p. m. ? $ feeds 1 juv. By 1 juv. Swallowed by $ 

4:41 p. m. ? 6 feeds 2 juvs. 

5:52 p. m. ? Ad. feeds 1 

juv. 
5:53 p. m. ? $ feeds 1 juv. 

5:55 p. m. ? 6 feeds 1 juv. By 1 juv. 6 flies away with ex- 

crement in bill 

General Remarks on Table V 

The observations on this date were made between 7:05 and 
11 :05 a. m. and between 3 -.00 and 6 :02 p. m. during which pe- 
riod the young were fed thirty-nine times. As before, the male 
usually announced his arrival at or near the nest by a low trill. 

Under the caption i i excreta sac removed by 6" the observer 
was not sure whether the excreta was swallowed or simply re- 
moved. In some cases the adults flew away with the excreta 
sac in the bill. Whether it was subsequently swallowed was 
not ascertained. 

The nestling fed at 9 :09 was one of the three that had been 
fed by the male at 9 :07. It still seemed that the parents used 
little selection or discrimination in feeding the young. At 9 :16 
the nestling first fed was the one that had been neglected at the 
two preceding feedings. 

At 3 :25 both parents were away from the nest and the nest- 
lings were apparently suffering from the heat. Neither adult 
was at the nest between 4:43 and 5:52, an unusually long 
absence. 



NESTING HABITS OP HERMIT THRUSH 15 



TABLE VI— August 5 



Time of 
feeding 



Kind of 
food 



9:40 A. M. 
9:45 A. M. 

9:50 A. M. 

9:55 A. M. 

10:02 A. M. 



10:10 A. M. 

10:14 A. M. 

10:16 A. M. 

10:27 A. M. 

11:14 a. m. 

11:16 a. m. 
11:18 a. m. 



11:22 A. M. 

11:24 a. M. 

11:25 a. M. 

2:02 p. m. 



2:07 p. M. 



? 

? 

Larva 



Insect 
Gryllids 

Gryllids 

Insect 
Green larva 



Gryllid 

? 

? 
Gray Lepid. 
larva 



2:17 p. m. 3 Gryllids 



2:22 p. m. 
2:41 p. m. 

2:51 p. m. 

2:57 p. M. 

3:05 p. m. 
3:17 p. m. 

3:30 p. m. 

3:31 p. m. 

4:00 P. M. 



1 Gryllid 
1 Gryllid 



Remarks 



Disposition 
of excreta 



Remarks 



Swallowed by $ 
Swallowed by 6 
(leaves at once) 



$ feeds 1 juv. By 1 juv. 
6 feeds 1 juv. By 1 juv. 

9 feeds 1 juv. 
$ feeds 1 juv. 
6 feeds 1 juv. 

(leaves at 

once) 
$ feeds 1 juv. 

(leaves at 

once) 

6 feeds 1 juv. By 1 juv. 6 leaves with excre- 
ment in bill 
6 feeds 2 juvs. 6 picks up excrement from bot- 
tom of nest and flies away 
$ feeds 1 juv. $ flies away with 

excrement in bill 
6 feeds 1 juv. 
(leaves at once) 
$ feeds 1 juv. 
$ feeds 1 juv. 

(flies away 

at 11:19) 
6 feeds 1 juv. 
6 feeds 1 juv. 
$ feeds 1 juv. 
6 feeds 1 juv. 

(leaves at 

once) 
6 feeds 1 juv. 

(leaves at 

once) 

$ feeds 3 juvs.l juv. deposits pellet of excre- 
ment in nest; seized by $ who 
flies away at once 
$ feeds 1 juv. By one juv. — not the one fed — 
swallowed by 2 



1 Gryllid & 
1 Acridiid 
Gryllid 

Gryllid 

1 Gryllid & 

2 Acridiids 



Green lepid. 
larva 



6 feeds 1 juv. 
(leaves at 
once) 
6 feeds 2 juvs. 



6 received pellet of excrement 
and flew away 
$ feeds 1 juv. $ waits a few seconds for pellet 
of excrement and flies away 



$ feeds 1 juv. 
$ feeds 3 juvs. 

$ feeds 1 juv. 

& feeds 1 juv. 

6 feeds 1 juv. 



$ receives pellet of excrement 
from 1 juv. and flies away 
$ swallows pellet of excrement 
and flies away 

6 swallows pellet of excrement 
and flies away 

6 swallows pellet of excrement 
and flies away 



16 IOWA STUDIES IN NATURAL HISTORY 

General Remarks on Table VI 

Observations were made on this date between 9 :30 and 11 :30 
a. m. and between 2:00 and 4:02 p. m. during which time the 
young received twenty-seven feedings. 

The nestlings appeared more active than at any previous 
date, moving about in the nest, scratching their heads and eyes 
with their feet and pecking at their own plumage as if dressing 
and preening it. 

At 10:35 the female, after an absence of eight minutes, ar- 
rived at the nest without food but remained for only three min- 
utes; this time she occupied in pulling and pushing the nest 
materials about as if to make the home more tidy. 

At 11 :27 'the observer noted the female chasing a grasshop- 
per near the nest ; she was unsuccessful in her attempts to catch 
the insect. 

Again at 3:57 p. m. the female arrived without food; upon 
her arrival all the mouths opened as usual and the adult pecked 
the inside of the mouth of one nestling as if to make him be- 
lieve he were being fed. The ruse seemed to have the effect of 
quieting the youngster. 

TABLE VII— August 6 

Time of Kind of Remarks Disposition Remarks 

feeding food of excreta 

3:11 P. M. ? $ feeds 1 juv. 

3:23 p.m. Insect 6 feeds 1 juv. £ receives pellet of excrement 

and flies away 
3:48 P. M. Larva $ feeds 2 juvs. None 

3:51 P. M. Insect 6 feeds 1 juv. 

4:10 P. M. Insects $ feeds 3 juvs 

4:55 P. M. Insect $ feeds 1 juv. 

General Remarks on Table VII 
Observations were conducted only between the hours of 3 :05 
and 5:06 p. m. during which time the young received six feed- 
ings. 

The adults remained away from their brood a great deal of 
the time, and the number of feedings was somewhat reduced, 
averaging but three per hour. 

The nestlings were now so large as to occupy almost the en- 



NESTING HABITS OF HERMIT THRUSH 



17 



tire space within the nest, leaving little room for the parent who 
often sat at the edge looking at her brood. The young birds 
were well feathered and appeared more alert to outside dis- 
turbances than before. Tkey flapped their wings from time to 
time in. an apparent attempt to leave the nest and pulled and 
tugged at their plumage as if to clean it. 

At 3:47 the female returned without food, remained but a 
moment, then flew away. Again at 4:32 the female returned 
without food and remained sitting on the edge of the nest look- 
ing at the nestlings. 



Time of 
feeding 




31 A. M. 
40 A. M. 

57 A. M. 



10:24 A. M. 

10:30 A. M. 
10:37 A. M. 



TABLE VIII— August 7 
Kind of Remarks Disposition Remarks 



food 



of excreta 



Acridiid 



Larva 

Black insect $ feeds 1 

& Acridiid 



Ad. feeds 1 

juv. 
Ad. feeds 3 

juvs. 
Ad. feeds 2 

juvs. * 
Ad. feeds 1 

juv* 
Ad. feeds 1 

juv« 
Ad. feeds 1 

juv, 
Ad. feeds 

same juv 

at 8:17 
Ad. feeds 1 

juv, 
Ad. feeds 1 

juv. 
Ad. feeds same 

juv, as at 

8:40 
Ad. feeds 1 

juv. 

$ feeds 3 juvs. 
juv. 



as 



Ad. leaves after picking up ex- 
crement 

Ad. flies away at once with ex- 
crement in bill 

Ad. waits in vain 2 minutes for 
juv. to defecate — flies away 

Ad. flies away with excrement 

Ad. flies away with excrement 
Ad. flies away with excrement 
Ad. flies away with excrement 



10:40 A. M. Acridiid Ad. feeds 1 



None 

By 1 juv. $ flies away with it 
1 juv. $ flies away with it 



By 



3:50 p. M. 
3:55 p. M. 
3:57 p. M. 

4:30 P. M. 



Larvae 



3uv. 

6 feeds 1 

6 feeds 1 



juv. By 1 juv. 6 flies away with it 
juv. By 1 juv. 6 flies away with it 

$ feeds 3 juvs. Not until $ swallows it 
4:01 

6 feeds 1 juv. 



18 IOWA STUDIES IN NATURAL HISTORY 

General Remarks on Table VIII 

Observations were conducted between the hours of 7:20 and 
11 :00 .a m. and between 3 :00 and 5 :00 p. m. during which period 
eighteen feedings were administered and excreta sacs were 
voided twenty-one times. 

The nestlings appeared even more restless than on the pre- 
ceding day. They were continually shifting their positions, 
preening their feathers, trying their wings and pecking the 
side of the nest or one another. 

The adults absented themselves for considerable periods of 
time. Neither parent visited the young between 3 :00 and 3 :30 
p. m. at which time the male returned without food and re- 
mained at the edge of the nest for twelve minutes. 

At 9 : 16 one of the adult birds suddenly swooped down from a 
nearby perch, picked up a voided excreta sac and carried it 
away; again at 9:24 and 9:38 this performance was repeated. 
At 9:46 the female returned cautiously, obtained a voided ex- 
creta sac and flew away. Excreta sacs were removed by the 
adults also at the following hours: 10:07, at which time two 
sacs were voided by different birds, 10 :15, 3 :45, 4 :04 and 4 :44. 
At none of these times were the adults on the nest but appar- 
ently they were on watch near by. Food was not brought 
on any of these visits which were apparently solely for the re- 
moval of the excreta sacs. 

At 8 :43 a chipmunk appeared near the blind and immediately 
upon discovering it the female dashed at the rodent from a 
near by log. She followed the intruder with much pecking and 
flapping of wings until he sought the friendly refuge of the 
mess tent a few yards away. 



OBSERVATIONS ON AUGUST 8 

On August 8 observations were begun at 7 :00 a. m. when both 
parents were absent from the nest. While the writer was at- 
tempting to lift up one of the young birds in his hands it es- 
caped, and, at the same time, two of the other nestlings with 
much squawking, fluttered off through the ferns and bushes 
amid the excited cries of the parents in the low branches of 
trees a few feet away. In its effort to repel the intruder one 
of the adult birds flapped him on the head with its wings. Dur- 



NESTING HABITS OP HERMIT THRUSH 19 

ing all this excitement one nestling remained on the nest, but 
at 7 :03 it too left, half flying, half running through the blue- 
berry bushes. The young were by this time well scattered and 
the adult birds called every few seconds for over an hour, the 
nestlings answering at intervals. 

At 7 :07 the female returned to the nest which now contained 
only the addled egg and three excreta sacs with one of which 
she immediately flew away. At 7:10 she returned for another 
sac and a minute later she flew back for a third sac which she 
carried away. She did not seem excited at the absence of the 
nestlings and apparently was preparing the nest for further 
use. 

The female visited the nest again for a moment at 7 :13 and at 
7:48 she returned, pecked two or three times in the bottom, 
walked across it and flew away, returning once more at 7:53 
when the same performance was noted. 

At 8 :10 one of the adults with food in its bill alighted on a 
low limb of a birch tree near by; every few seconds it called 
to the young. Fifteen minutes later an adult bird carrying 
food was again observed in the vicinity. It uttered an unbroken 
series of low clucks and after a moment flew to the ground 
where one of the young was calling and probably fed it, for not 
a, sound was heard from this spot for more than a minute. 

Although the family was now dispersed the adults seemed 
to be as active as ever in feeding the nestlings and not much 
time was lost in idleness once the disturbance of the morning 
had abated. 

The nest and vicinity were again inspected in the evening 
but no trace of the adults or young was discovered; only the 
addled egg remained. Our observations were thus brought to 
a rather sudden and untimely end. However, it seems certain 
that in another twenty-four hours the young would have left 
the nest of their own accord instead of in the rather unsum- 
mary and irregular manner herein described. 

Although nothing was seen of the young thrushes subsequent 
to this episode it is likely that they remained in the vicinity for 
a time or at least until they could fly well. Concerning the 
habits of this species after deserting the nest Audubon re- 



20 



IOWA STUDIES IN NATURAL HISTORY 



marks. 2 "The young run after the parents, on the ground, for 
several days after they leave the nest." Similar and corrobor- 
ative observations have since been made on this point although 
the writer was unable to follow up this phase of the study to 
his own satisfaction. 

TABLE IX— TABULAR SUMMARY 

Date No. hrs. observation No. times food was brought to 

young 



July 31 


4 hrs. 


52 min. 


12, 


6 6, 


$ 6 


August 1 


2 hrs 


18 min. 


10, 


6 4, 


$ 6 


August 2 


8 hrs. 


18 min. 


38, 


6 20, 


$ 18 


August 3 


4 hrs. 


6 min. 


26, 


6 15, 


9 11 


August 4 


7 hrs. 


2 min. 


39, 


6 21, 


$ 15 sex undetermin- 
ed on 3 occasions 


August 5 


4 hrs. 


2 min. 


27, 


6 11, 


$ 16 


August 6 


2 hrs. 


1 min. 


6, 


6 2, 


$ 4 


August 7 


5 hrs. 


40 min. 


18, 


6 3, 


$ 3 sex undetermin- 
ed on 12 occasions 



Total 38 hrs. 29 min. 176 

GENERAL SUMMARY 

1. Observations on the young in the nest were conducted 
over a period of thirty-eight hours and twenty-nine minutes 
between July 31 and August 8. During this time 176 feedings 
were administered. 

2. Brooding was carried on only by the female. 

3. At no time during our observations were the young in- 
dulged with a vegetarian diet, although the adults were seen 
to eat blueberries on at least two occasions. The food of the 
nestlings was entirely of insects either in the larval or adult 
stage. 

4. On many occasions the parent bird fed more than one 
nestling. At no time was feeding by regurgitation observed. 

5. At no time during our observation was the male hermit 
thrush heard to sing, although the familiar high-pitched call 
very like that of the cedar waxwing was given often. 

6. The nestlings did not always void the excreta sac immedi- 
ately after being fed, sometimes not for several minutes or 
even longer after the act of feeding occurred. 

7. During approximately the first half of the nestling period 
the adults swallowed the excreta sac. During the latter half of 



2 Audubon, John James, American Ornithological Biography, I, 1831, 303. 



NESTING HABITS OF HERMIT THRUSH 21 

the period the sae was usually, although not invariably, carried 
away. The female was seen to swallow an excreta sac at the 
nest on August 7. 

8. Toward the close of the nestling period the adults re- 
mained away from the nest for considerable intervals. Some- 
times the adults returned to the nest without food and only for 
the purpose of carrying away the voided excreta sacs. 

9. The male and female each had their own particular mode 
of approach to the nest, the female usually alighting a few feet 
from it and running quietly up to the young while the male 
usually alighted almost immediately at the nest with food. He 
was more nervous and noisy in his actions than the female. 



FIRST SEEmS No.J O _ _____ J ANUARY 1, 1921 

UNIVERSITY OF IOWA 
STUDIES 



STUDIES IN NATURAL HISTORY 



Volume IX Number ■■ 



THE EROSIONAL HISTORY OF THE 
DRIFTLESS AREA 

by 
ARTHUR C. TROWBRIDGE 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 



Issued semi-monthly throughout the year. Entered at the post office at Iowa City* 
Iowa, as second class matter. Acceptance for mailing at special rates of postage 
provided for in section 1103, Act of October 2, 1917, authorized on July 3, 1918. 



UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 

Professor Charles Cleveland Nutting, M. A., Editor 



Continuation of Bulletin from the Laboratories of Natural History of 
the State University of Iowa 

Volume IX Number 3 



THE EROSIONAL HISTORY OF THE 
DRIFTLESS AREA 

by 
ARTHUR C. TROWBRIDGE 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 



PART I 

MULTIPLE EROSION CYCLES IN 

PRINCIPLE 



CONTENTS 

Page 

Introductory Sketch 7 

More than One Cycle of Erosion 9 

Theoretic Considerations - 9 

Evidences of More than One Cycle 12 

Interrupted Profile 12 

Stream Terraces _-_--13 

Intrenched Meanders 15 

Associated Sets of Straight and Crooked Streams 19 

Antecedent Streams - 21 

Windgaps - - - _ 24 

Even-crested Summit Areas 26 

In Regions of Folded Strata 27 

In Regions of Horizontal or Nearly Horizontal 

Strata - - - - - 28 

In Regions of Igneous Rocks ------ 30 

Intermediate Plains - - 31 

Fluvial Deposits on Uplands - - 33 

Combinations -- _ _ _ _ _ 34 

More than Two Cycles - - -37 

The Determination of Diastrophic Events - - - 39 
The Number of Movements --------39 

The Nature of Movements 40 

Uniform Uplift 40 

Uplift with Tilting 40 

Uplift with Warping 41 

Uplift with Faulting 43 

Subsidence -- 44 

The Amount of Movement -- 44 

The Determination of Dates 45 

The Ages of Old Erosion Surfaces ------ 45 

The Dates of Movement 47 

The Duration of Geologic Time 48 

Conclusion of Part I - - 49 



PART I 
MULTIPLE EROSION CYCLES IN PRINCIPLE 

INTRODUCTORY SKETCH 

First steps in the interpretation of the erosional histories 
of regions were taken when (1) the processes of land de- 
gradation by streams were worked out, (2) the limits of 
change were recognized, and (3) the stages of reduction, 
expressed in the terms youth, maturity, and old age were 
described. 

Second steps were taken by Dutton 1 who conceived that 
the Arizona plateau had been degraded to low levels and 
then had been uplifted in such a way as to start new cycles 
of erosion. Following the lead of Dutton but bringing to 
bear upon their studies critical and analytical methods 
Willis 2 , Hayes and Campbell 3 , Davis 4 and others wrote his- 
tories of parts of the Appalachian mountains, not only pre- 
senting and explaining evidences of more than one cycle 
of erosion, but working out evidences of more than two 
cycles, describing the degree of completeness of reduction 
reached in each cycle, giving the geologic dates of each 
event in the erosional history of the region, interpreting 
the number, character and dates of uplift, etc. But, by its 
very thoroughness and accuracy, this work has led un- 
fortunately to confusion. Later the principles so well used 
in the Appalachian region were applied, with little con- 
sideration, to regions where their application was doubt- 
ful. Complex series of events were thus assigned to regions 
whose histories were simple, and there came to be more 
raised peneplains in literature than in the field. The care- 



1. Dutton, C. E., "Tertiary History of the Grand Canyon District," U. S Geol 
Surv., Monograph No. 2, 1882. 

2. Willis, Bailey, The Northern Appalachians, Physiography of United States, 1895 
pp. 169-202. 

3. Hayes, Willard C, and Campbell, M. R., "Geomorphology of the Southern Appa- 
lachians," Nat'l Geog. Mag., Vol. VI (1894), pp. 63-126. 

4. Davis, W. M.. "Rivers and Valleys of Pennsylvania," Nat'l Geog. Maa. Vol I 
(1889), pp. 183-253. 

7 



8 IOWA STUDIES IN NATURAL HISTORY 

lessness of physiographic interpretation during this time 
was followed by a period of reaction ushered in by the 
criticism of Tarr 1 who seems to have been the first to sound 
a note of warning and present the idea that not all flattish 
surfaces above streams are old peneplains. 

But now Tarr's argument in turn seems to have been 
carried beyond the point intended by its author, for many 
geologists having convinced themselves and others that 
some physiographic features which have been described as 
raised peneplains are not old erosion surfaces, have pro- 
ceeded to the extreme conclusion that there are no such 
things as raised peneplains and consider no evidence either 
in favor of or against the peneplain theory in working out 
the histories of regions in the field. The conclusion that 
because some upland flats are not old peneplains there is 
no such thing as raised peneplains is as unwarranted and 
as great a detriment in the search for truth as was the con- 
clusion of the older physiographers that because some up- 
land surfaces were old peneplains, all such surfaces could 
be identically interpreted. 

The extreme reaction against the peneplain theory seems 
to be giving way at present to a revival of interest in the 
subject, as shown in the spirited discussion among Umple- 
by 2 , Atwood 3 , Blackwelder 4 , and Rich 5 , all of whom assume 
the existence of a raised peneplain and differ among them- 
selves only in regard to the age of the plain. R. T. Cham- 
berlin G also clearly believes in the peneplain theory, as evi- 
denced in one of his latest productions. Physiographers seem 
still to be about evenly divided into two groups, the mem- 
bers of one of which disregard the peneplain theory en- 



1. Tarr, Ralph S., "The Peneplain," Am. Geol. Vol. XXI (1898), pp. 351-371. 

2. Umpleby, Joseph B., "An Old Erosion Surface in Idaho — Its Age and Value as a 
Datum Plane," Jour. Geol., Vol. XX, No. 2, pp. 139-147 ; "An Old Erosion Surface in 
Eastern Utah — Its Age and Value in Time Determination," Abstract, Wash. Acad. 
Sci. Jour., Vol. 2, pp. 109-110, 1912; "The Old Erosion Surface in Idaho," Jour. 
Geol., Vol. XXI. pp. 224 et seq, 1913. 

3. Atwood, Wallace W., "The Physiographic Conditions at Butte, Montana and 
Bingham Canyon, Utah When the Copper Ores in These Districts were Enriched," 
Econ. Geol., Vol. XI, pp. 687-740, 1916 ; "Physiographic Conditions and Copper En- 
richment," Econ. Geol., Vol. XII, pp. 545-547, 1917. 

4. Blackwelder, E.. "Physiographic Conditions and Copper Enrichment," Econ. 
Geol., Vol. XII, pp. 541-545, 1917. 

5. Rich, John L., "An Old Erosion Surface in Idaho: Is it Eocene," Econ. Geol., 
Vol. XIII, No. 2, March, 1918. 

6. Chamberlin, R. T., "The Building of the Colorado Rockies," Jour. Geol., Vol. 
XXVII, pp. 145-251. 



EROSION AL HISTORY OF DRIFTLESS AREA 9 

tirely in field work, while those of the other group believe 
that raised peneplains exist, but are doing little construct- 
ive thinking or writing in substantiation of the theory itself. 

It now seems appropriate to bring together all the 
methods which have been used in the interpretation of ero- 
sional histories, to analyze each method, to discuss its uses 
and abuses, and to attempt to assign to each its proper 
value. These are the purposes of this paper. 

Both in the analysis of the principles and in the con- 
struction of the paper, the writer has been greatly assisted 
by Professors R. D. Salisbury, M. M. Leighton, and Leroy 
Patton, of whom all were so kind as to read the first draft 
and to make helpful suggestions for incorporation in the 
final paper. 

MORE THAN ONE CYCLE OF EROSION 

Theoretic Considerations 

The rate of land degradation by streams has been esti- 
mated at 1 foot in 9000 years, under conditions which ex- 
ist in the United States 1 . If the average altitude of the 
land today be taken as 2300 feet it would take more than 
20,000,000 years for streams to reduce the land to sea level. 
But the process of degradation becomes slower as the lands 
are reduced. This progressively decreasing rate of re- 
duction carried through from youth to the ideal base- 
levelled condition would involve an amount of time 
approaching infinity. Indeed, it seems doubtful if geologic 
time has been as long as a complete cycle of erosion would 
be. But, though it be uncertain that lands were ever re- 
duced to base level, they have been reduced to low levels ; 
that is, perfect baselevel plains are probably not formed, 
but peneplains may be. There is no theoretic reason for 
believing that extensive areas have not been peneplained 
again and again. 

If the history of land surfaces were merely a matter of 
formation and subsequent degradation, most lands should 
to-day be in the condition of peneplains. The fact that 



1. Water Supply Paper No. 234, U. S. Geological Survey, pp. 78-? 



10 IOWA STUDIES IN NATURAL HISTORY 

high lands exist demonstrates that there are forces which 
give lands high altitudes and that these forces, on the 
average, at least balance the processes of degradation. 
These renewing forces are diastrophic. 

There is not perfect agreement among geologists con- 
cerning some of the phases of diastrophism, but the prin- 
ciples involved in land formation are fairly well agreed up- 
on. Lands are due to lithospheric contraction. As the 
lithosphere shrinks, the ocean basins settle more than the 
continental platforms, the capacity of the ocean basins in- 
creases, the water withdraws from the continental plat- 
forms, and lands are increased in area or height or both. 
If lands have been reduced to low levels and the lithosphere 
shrinks, these lands are left higher by the withdrawal of 
the sea and a new cycle of erosion is inaugurated. 

If diastrophism were a continuous process, land would 
be reduced slowly if general degradation exceeded uplift, 
it would remain at a generally constant level if degradation 
and uplift were equal, and it would become slowly higher if 
uplift took place more rapidly than degradation. The 
height of land would depend upon a balance between dias- 
trophic uplift and degradation by all agents of which run- 
ning water is chief. 

Pronounced diastrophism manifests itself periodically 
rather than continuously. Degradation goes on uninter- 
ruptedly between periods of diastrophism, but sooner or 
later the uplift comes, degradation is renewed and new 
cycles of erosion are inaugurated. 

The relative duration of erosion cycles and diastrophic 
periods now becomes important. If the diastrophic period 
is longer than the erosional cycle, land is totally destroyed 
and then formed again. If the periodic uplifts come so 
frequently and the land is uplifted each time so high that 
the land added by each uplift is not entirely destroyed be- 
fore the next uplift, the history is one of land increase, 
partial degradation, further increase, partial degradation, 
and so on. Neither the cycle of erosion nor the diastrophic 
period is of determinate duration, and therefore there can 
be no invariable rule in their relative values, but a study 



EROSION AL HISTORY OF DRIFTLESS AREA 11 

of geologic history leads to the conclusion that the complete 
erosion cycle is in most cases at least longer than the dias- 
trophic period. This being the case most, cycles of erosion 
are interrupted by uplift and few if any cycles of erosion 
have been complete. Doubtless there have been cases in 
which lands have been so reduced by all the agencies at 
work on their surfaces and by deposition in the sea that 
the sea spread over them, but probably there has never 
been a time when whole continents have been so destroyed. 
In any case the present paper deals only with those surfaces 
which have not been reduced to the condition of sub- 
mergence. 

The question now arises as to what stage of degradation 
is reached by the average surface before the cycle is in- 
terrupted. Tarr 1 has argued that because there are few if 
any low level plains to-day which have been developed by 
streams, there never have been any and that pleneplains have 
never existed. This conclusion is hardly warranted, for the 
present day may be one closely following an uplift. 

The writer would agree that probably no continent-wide 
and perfectly flat erosional plains have been developed in 
the past, but he cannot agree that smaller areas have not 
been brought to an earlier stage of reduction which might 
be defined by the term peneplain. 

It seems unavoidable to suppose that erosion cycles might 
be interrupted either in youth, maturity, or old age. But 
interruption in old age should theoretically be most common, 
for degradation takes place most rapidly in youth and 
maturity, and is much slower in old age. Land is reduced 
rather quickly to the peneplain stage but further reduction 
to complete base level is almost infinitely slow. That is, in 
a complete cycle the stage of old age would be longer than 
youth and maturity. 

If a region reached old age in the first cycle and has gone 
only to maturity of the second, some of the characteristics 
of the first cycle will have held over into the second, and 
the history should be ascertainable. If on the other hand, 
a region is in youth of the first cycle when the interruption 

l7~Tarr, R. S., "The Peneplain," Am. Geol., Vol. 21, pp. 351-370. 



12 IOWA STUDIES IN NATURAL HISTORY 

occurs, and it is in youth of the second cycle at the time of 
observation, it would be almost impossible to determine that 
it had entered upon a second cycle. It would be still more 
difficult to interpret the history of a region in which a cycle 
of erosion had gone so nearly to completeness that all evi- 
dences of a former cycle had been obliterated. Indeed, 
satisfactory determination seems to be almost limited to 
cases where each cycle of erosion is less nearly complete 
than those which preceded. 

Evidences of More Than One Cycle of Erosion 
Several different physiographic features have been used 
as criteria for more than one cycle of erosion in the history 
of land surfaces. If their relative values are to be fixed, 
it is necessary that each of these features be analyzed. 

Interrupted Profile 
Streams which have reached grade, normally have con- 
cave profiles with progressively decreasing gradients from 
source to debouchure, (abc Fig. 1). If such a profile be 



Fig. 1. A diagram in explanation of interrupted profile due to rejuvenation of a 
stream, abc is the profile of the stream in old age of the first cycle when sea level 
was cd. abe is the profile after sea level has taken the position ef and the rejuve- 
nated stream has worked headward to be. 

developed in old age of a first cycle of erosion and if the 
region then be uplifted so that a steep bordering slope is 
formed, rejuvenating the stream, degradation will be re- 
newed first near the mouth of the stream, where a new 
valley and a new profile will be developed. As this new 
valley, with its profile, is extended headward, there will 
come a time when there is a double or interrupted profile 
(abe Fig. 1) in which the upper portion was made in the 



EROSION AL HISTORY OF DRIFTLESS AREA 13 

first cycle and the lower portion in the second cycle of 
erosion. 

There are, however, distinct limitations to the use of in- 
terrupted profiles as criteria of rejuvenated streams. Any 
stream which flows across resistant to non-resistant rock, 
and which has not yet brought the resistant rock to grade, 
may develop an interrupted profile in a single cycle of 
erosion. (Fig. 2). If a relatively flat surface emerged 




Fig. 2. Diagram showing how interrupted profile abc may be developed in a single 
cycle of erosion with reference to sea level cd, due to inequalities in the hardness 
of the rock formations. 

from the sea and came to stand distinctly above its sur- 
roundings, as in the case of a plateau, water would run 
down the gently sloping summit surface and down the steep 
bordering slope and would acquire an interrupted profile 
which would last until the lower portion of the stream had 
worked headward to the very source of drainage. Any 
region therefore having unequally resistant rock or any 
flattish surface bordered by a distinct descent, may have 
streams with interrupted profiles. 

In the abstract, interrupted profiles in the streams of a 
region merely suggest that the region may be in the second 
cycle ; they do not furnish strong evidence, much less proof, 
of a second cycle. They amount to strong evidence, only 
after all other possible interpretations have been eliminated 
by careful study in the field. 

Stream Terraces 
The uplift of a surface in which a stream has previously 
reduced its bed to grade and developed a valley flat causes 
the stream to intrench itself in the flood plain and form 



14 IOWA STUDIES IN NATURAL HISTORY 

terraces. (Fig. 3). Terraces so formed involve more than 
one cycle of erosion. 

However, stream terraces are formed in a single cycle 
of erosion (1) by unequal widening at the levels of un- 
equally resistant horizontal strata, (2) by the partial re- 
moval of glacial or fluvio-glacial fills in valleys, (3) by the 



Fig. 3. Diagram showing how stream terraces may be formed by uplift of the sur- 
face after a stream has developed a valley flat. The profile abcdfgh is the cross sec- 
tion of the valley after grade level AA has been reached. By uplift a new level was 
established at BB, the rejuvenated stream cut the new valley cef, and terraces be 
and fg were formed. 

recession of falls through temporarily graded valley bot- 
toms, (4) by the removal of dams, such as landslides, lava 
flows, sand dunes, etc., (5) by renewed erosion of a valley 
flat, due to increased volume in a pirate stream, (6) by the 
intrenchment of graded valley bottoms as a stream acquires 
greater length and more and longer tributaries and comes 
to drain a larger area, and increases in volume, (7) by a 
graded stream receiving less load from its head as gradients 
are lowered, and intrenching itself, (8) by a stream picking 
up much fine material from its flood plain and dropping 
less coarse material in its place, (9) by the shifting of 
meander belts down stream, etc. These are common pro- 
cesses and all the events in the history of many stream ter- 
races take place in a single erosion cycle. 

From the above, it is clear that terraces along the streams 
of a region can seldom be used as adequate evidence of more 
than one cycle of erosion. On the other hand, if stream 
terraces can be analyzed and all possibilities can be elimi- 
nated except the one involving more than one cycle of ero- 
sion, they might be considered to be more than merely sug- 
gestive of a second cycle, especially if there are other evi- 
dences which corroborate the conclusion. 



EROSION AL HISTORY OF DRIFTLESS AREA 15 

Intrenched Meanders 

Meandering streams in young valleys have long been 
used as evidence of second cycles of erosion in regions. By 
some they have been used as proof, even in regions which 
afford practically no other evidence of more than one cycle 
of erosion 1 . As commonly interpreted, the history of in- 
trenched meanders is somewhat as follows: (1) in a first 
cycle of erosion a stream reaches grade, becomes sluggish, 
and develops a broad valley flat and broad meanders; (2) 
the surface is uplifted relative to sea, the stream is re- 
juvenated, and intrenches itself without changing its mean- 
dering course. 

The value of intrenched meanders as evidences of more 
than one cycle depends upon the definition of meanders, and 
the accuracy with which they may be distinguished from 
other crooks in streams. During all stages of their history 
all streams are more or less crooked. The first water which 
flows over a newly formed land surface concentrates in 
crooked courses, (1) where there are original depressions 
irregularly distributed, (2) where unequally resistant 
materials are not arranged in orderly fashion, or (3) where 
there are differences in the amount of water supply. If in 
this stage the streams are flowing over a low, almost flat 
surface, they are easily deflected and curves are. developed 
which are identical in principle with meanders developed 
on valley flats by streams at grade. In this first stage of 
its history such a stream is said to be consequent and its 
curves might be called consequent crooks. Continuing their 
histories, such streams lengthen by head ward erosion, their 
heads being extended up the steepest slopes, through the 
least resistant material, and toward the greatest water 
supply. Inasmuch as these determining conditions are 
irregularly distributed on most surfaces, this stage of 
stream adjustment involves the development of a second 
set of crooks which are also consequent. As the cycle of 
valley development and the cycle of land reduction continue, 
a third stage is reached in which stream piracy takes place, 



1. Gannett, Henry, "Physiographic Types," Folio No. 1, U. S. Geol. Surv. Fourth 
map and page 2. 



16 IOWA STUDIES IN NATURAL HISTORY 

streams are diverted and beheaded, drainage is reversed in 
direction, and still other crooks are developed. During any 
one of these first stages in stream adjustment, streams may 
reach temporary grade, on the upstream sides of resistant 
rock or upstream from glacial dams, blocking lava flows, 
landslides, or artificial dams, and develop meanders. Finally, 
when the stream has developed its valley to old age, has 
large tributaries and large volume, and has reached a still 
later stage of adjustment, the stream is sluggish, is likely 
to be depositing, is easily turned from side to side, and 
stream meanders, as the term is commonly applied, are 
formed. The crooks developed in the first three stages as 
outlined above, may be formed and intrenched in a single 
cycle of erosion. It would require an uplift and a second 
cycle of erosion for the intrenchment of the meanders de- 
veloped in the fourth stage. If meanders be defined as the 
curves acquired by a stream in the late stages of valley de- 
velopment, intrenched meanders would be proof of a second 
cycle of erosion. But a difficulty lies in distinguishing such 
meanders from crooks developed during earlier stages. 

The writer does not see any means of distinguishing 
crooks developed in youth on a flat surface (Fig. 4, A A and 
BB) nor meanders formed on temporary flood plains up- 
stream from obstructions, from meanders developed in old 
age (Fig. 4 DD and EE). It seems even difficult, and in 
many cases impossible to distinguish the meanders of old 
age from ordinary crooks due to topography, irregularities 
of resistance, or stream piracy (Fig. 4 CC). 

It has been said that meanders differ from other crooks, 
(1) in being more symmetrical, (2) in being so arranged 
that every portion of the stream course is a part of two 
meanders, and (3) in having a ratio of distance across the 
necks of meanders to distance around the meanders of about 
1 to 7. A study of the courses of the Missouri and Sioux 
rivers on the Elk Point, S. D. topographic sheet, the Mis- 
souri and Platte rivers on the Leavenworth, Kas. sheet, Mis- 
sissippi river on the Baton Rouge, La. sheet, Missouri river 
on the Marshall, Mo. sheet, the Wabash, White and Patoka 
rivers on the Princeton, Ind. sheet, the Wabash and Little 



EROSION AL HISTORY OF DRIFTLESS AREA 17 




Fig. 4. A- series of plats of stream courses of different histories. 

^nM^cSS T + th i? C ° UrSe ° f Map i e river taken from the Casselton, No. Dak. topo- 

Sef on low, fiat Jand. 3 * COnSGQUent COUrse in youth of its fir st cycle. Curves devel- 

g J lacia? dr C ift^ Ver ' Wat * rl °°' Wis ' sheet " A consequent stream on the surface of 
and topography^ 61 '' Wilmington ' Vt ' sheet - A stream in harmony with rock hardness 
DD Platte river, Leavenworth, Kas. sheet. Meanders developed in old age 
&E Big Sioux river, Elkpoint, So. Dak. sheet. Meanders developed in old age. 



18 IOWA STUDIES IN NATURAL HISTORY 

Wabash rivers on the New Haven, Ills, sheet, and Nemaha 
river on the Falls City, Nebr. sheet, all of which are streams 
with meanders formed in old age, shows that these three 
characteristics of meanders are more imaginary than real. 
Few if any distinguishable differences between the mean- 
ders of old age and crooks made in other ways are brought 
out by the comparison of the meandering streams referred 
to with typical crooked streams not in old age, such as Red 
and Buffalo rivers on the Fargo, N. D. sheet, Otter creek 
on the Brandon, Vt. sheet, Deerfield river on the Wilming- 
ton, Vt. sheet, Des Moines river on the Boone, Iowa sheet, 
San Joaquin river on the Westley, Cal. sheet, Tuolumne 
river on the Westport, Cal. sheet, Canadian river on the 
Brilliant, N. M. sheet, Stanislaus river on the Ripon, CaL 
sheet. There being no distinguishable differences between 
the meandering streams referred to above and ordinary 
streams which have never reached old age, it follows that 
it is impossible to tell from the maps, after a study of the 
curves themselves, whether intrenched meanders of the 
second cycle of erosion or ordinary crooks of the first cycle 
are illustrated in the Brazos river on the Palo Pinto, Texas 
sheet, Monongahela river on the Brownsville, Pa. sheet, 
Canondoquinet creek on the Harrisburg, Pa. sheet, Grant 
and Platte rivers on the Lancaster, Wis. sheet, and Osage 
river on the Tuscumbia and Forsyth, Mo. (Fig. 5) sheets. 
Intrenched meanders might, however, in some cases at 
least, be distinguished from consequent crooks by the pres- 
ence of outer valley walls. If the meander belt is located 
within outer valley walls and the stream is intrenched, the 
curves would seem to have been inherited from the mean- 
ders of an old age stage of valley development in a pre- 
vious cycle. With this exception, which would rarely apply 
except in the early stages of a second cycle following a 
cycle which was interrupted before the valley walls became 
indistinct, intrenched meanders as evidence of more than 
one cycle in the erosional history of a surface would seem 
to have little if any value. Only in combination with other 
and more decisive evidences would they rise in other cases 
above the rank of mere suggestion. 



EROSION AL HISTORY OF DRIFTLESS AREA 19 

Associated Sets of Straight and Crooked Streams 

Although it seems impossible to distinguish intrenched 

meanders from other stream curves by a study of the curves 

themselves, comparison of a stream and its own tributaries 

will, in some cases at least, determine whether or not a 




Fig. 5. A plat of the course of White river taken from the Forsyth, Missouri top- 
agraphic map. The stream flows in a young valley, and its course has been inter- 
preted to be a series of intrenched meanders. Reference to Figure 4 brings out the 
danger in such interpretations. So far as the curves themselves are concerned, 
they might not be intrenched meanders, as that term is commonly applied, and the 
surface might have suffered only one cycle of erosion. 

crooked stream is in its second cycle. When a stream is 
old it meanders and has only a few tributaries which also 
meander. After rejuvenation, many other tributaries are 
developed, which do not meander. The early stages of a 
second cycle then would exhibit two sets of streams, one of 
which includes only a few large, conspicuously crooked 
streams, and the other set a large number of small, relative- 
ly straight streams. If all the streams of a region were 
formed in the same cycle under the same conditions, they 
should all show the same general character and degree of 
crookedness. If one set is curved and the other set straight, 
both cannot have been developed in the same cycle. (Fig. 6) 
It seems, therefore, that this association of one set of 
streams which meander and a second set the members of 
which are conspicuously more nearly straight affords 
strong evidence that the surface on which the two sets are 
thus associated is not in its first cycle of erosion. 



20 IOWA STUDIES IN NATURAL HISTORY 




Fig. 6. A plat of the drainage of the Pittsburg Quadrangle. There are two distinct 
sets of streams, one including the large and most crooked streams, and the other the 
smaller and straighter ones. The large streams have a sort of curve different from 
that of the small ones. It seems that the large streams must have been developed to 
something like their present sizes and must have had their present courses before the 
small streams were started. The interpretation seems warranted that the courses of 
the large streams were established in old age of the first cycle of erosion and the 
small streams in the second cycle. 



EROSION AL HISTORY OF DRIFTLESS AREA 21 

Antecedent Streams 

The value of antecedent streams as evidences of more 
than one cycle of erosion in a region depends upon the 
definition of the term antecedent. The term was originally 
applied by Powell 1 to streams which hold previously estab- 
lished courses as their beds are warped, folded, or faulted. 
The streams were supposed to degrade their beds as rapidly 
as the beds were warped up. Such a history does not 
necessarily involve more than one cycle of erosion, except 
in the places where up-warping occurs. 

Later the definition of antecedent streams was greatly 
broadened by Davis, Willis, and Hayes and Campbell, who 
applied the term to the Potomac, Susquehanna and other 
rivers of the Appalachian mountains. This whole region 
was folded and then peneplained, the rivers acquired their 
present courses on the peneplain, and then uplift of the 
whole surface took place and the streams intrenched them- 
selves in their old courses. According to this definition 
antecedent streams are those which develop courses inde- 
pendent of rock structures in old age of an erosion cycle 
and hold those courses after uplift. Such streams are im- 
portant evidences of more than one cycle. 

In a folded region, such as the Appalachian mountains 
at the end of the Paleozoic era, streams adjust their courses 
in several distinct stages during the first cycle of erosion. 
In stage I, the main streams flow parallel with the strike 
of the strata in the axes of the synclines and the tributaries 
flow down the limbs of the anticlines parallel with the dip 
and at right angles to the main streams. In this first stage 
the slope of the land controls the courses of the streams. 
In stage II, those streams acquire an advantage, which first 
penetrate resistant layers and come to flow on non-resist- 
ant layers parallel with the strike. In this stage the main 
drainage lines shift to the limbs or axes of the anticlines. 
(Fig. 7) . Now it is the resistance of the rock and the rock 
structures which control the courses of the streams. Finally 
when old age has been reached and all or most of the rocks 



1. Powell. J. W., "Explorations of the Colorado River of the West and Its Tribu- 
taries," p. 163. 1875. 



22 



IOWA STUDIES IN NATURAL HISTORY 



Have been reduced to grade, those streams which flow the 
shortest distance to the sea will have higher gradients than 
others and will therefore gradually absorb these other 
streams. The result is a drainage system in which the 
main streams flow the shortest distances to the sea irres- 




Fig. 7. Diagram to illustrate the change from Stage I to Stage II of stream ad- 
justment in regions of folded strata. (After Davis). 

pective of rock structure or hardness, and even the tribu- 
taries flow into the mains by the shortest routes (Stage III, 
Fig 8). Near the divides where the streams are not at 
grade, tributaries may still be flowing parallel with the 
strike, controlled by the structure. In this third and final 
stage of adjustment the courses of the streams are again 
controlled by the topography, but the topography is not the 
same as it was in the first stage. Roughly, Stage I would 
correspond with youth of the cycle of erosion, Stage II with 
maturity, and Stage III with old age. 

If a region in which the streams have gone through the 
three stages of adjustment, be uplifted relative to the sea 
and the streams hold their courses during and after uplift, 
the streams in the second cycle would be antecedent accord- 
ing to the more recent use of the term. In a region of fold- 



EROSION AL HISTORY OF DRIFTLESS AREA 23 

ed strata during maturity, streams which have courses 
parallel or oblique to the dip and flow the shortest distance 
to the sea, afford good evidence that the region has suffered 
more than one cycle of erosion. 




Fig. 8. Diagram illustrating Stage III of 
stream adjustment. (After Davis). 

In case a region under investigation is not one of folded 
structures, the same general methods as outlined above may 
be applied. The stages of adjustment can be worked out 
and the corresponding stage of reduction. If the stage of 
reduction and stage of adjustment do not harmonize, the 
stream courses furnish evidence of more than one cycle of 
erosion. 

It must be recognized that by extremes in slope streams 
might work headward through hard rocks and that by ex- 
tremes in non-resistance, they might extend headward 
through topographic elevations so as to flow through water- 
gaps, all in the first cycle. It is not probable, however, that 
anything but the smaller streams of a region would in this 



24 IOWA STUDIES IN NATURAL HISTORY 

way develop courses which would appear to be out of har- 
mony with rock resistance and existing topography in a 
single cycle of erosion. 

Another case of antecedent streams involves superim- 
position. Streams which develop courses on newly formed 
surfaces, such as lava plains, emerging sea bottoms, or sur- 
faces of glacial drift, may cut through superficial deposits 
and become superimposed upon previously existing, irregu- 
lar, buried surfaces. Such streams may have courses en- 
tirely out of harmony with the resistance, structure and 
topography of the old surfaces. Superimposed streams are 
antecedent but they do not indicate that the youngest sur- 
face degraded has been reduced in more than one cycle of 
erosion. 

From the foregoing, it is seen that certain antecedent 
streams are significant of more than one cycle of erosion. 
If the main streams of a region show evidence of having 
reached a late stage of stream adjustment but if they are 
not in a late stage of erosion in the present cycle, they offer 
valuable and almost indisputable evidence of more than one 
cycle. The Susquehanna river shown in Fig. 9 practically 
proves that the region in which it has its course is not in 
its first cycle of erosion, if local warping under the stream 
and superimposition can be eliminated. 

Windgaps 
It has long been the prevalent opinion that most, if not 
all, windgaps are the result of diversions by piracy of 
streams flowing in narrows or watergaps across hard 
ridges, leaving the watergaps without water. If this is the 
origin of windgaps, they have some value as evidences of 
more than one cycle of erosion in the region in which they 
are found. Let a region of folded strata go to old age of a 
cycle of erosion and let the streams attain a final stage of 
adjustment following the shortest routes to the sea parallel 
or oblique with the dip of the strata. After uplift of the 
surface, new streams will be started which will adjust 
parallel with the strike on the less resistant formations. 
These streams under the new conditions will have the ad- 



EROSION AL HISTORY OF DRIFTLESS AREA 25 



vantage of the antecedent streams oblique to the strike and 
will behead the antecedent streams. This leaves windgaps 
where the antecedent streams flowed across hard forma- 











^> " ; ^ %\U 



Fig. 9. Part of the Harrisburg, Pa. topographic 
map, showing the antecedent course of the Susque- 
hanna river. Such a relation between stream 
course, topography, and rock structure proves that 
the surface has suffered more than one cycle of 
erosion. 

tions, provided these streams intrenched themselves in their 
old courses before piracy took place. 

In regions of folded strata there is possibility of piracy 
and the formation of windgaps in the first cycle of erosion. 
In passing from Stage I to Stage II of adjustment the main 
streams are diverted from courses on the synclines to cours- 
es on the limbs or axes of the anticlines, giving rise to 
drainage systems some portions of which are parallel with 



26 IOWA STUDIES IN NATURAL HISTORY 

the strike and other portions parallel with the dip. This 
stage is reached before the streams have reached their depth 
limits, and piracy may occur. Indeed, the change from 
Stage I to Stage II is not accomplished without piracy. In 
such cases streams parallel with the strike have the ad- 
vantage of streams flowing across the strike and windgaps 
are formed which might be indistinguishable from those 
due to piracy in the second cycle. 

Windgaps are not conspicuous in regions of horizontal 
strata nor in regions of massive rock, a fact which prac- 
tically limits the application of windgaps to regions of fold- 
ed or tilted strata. 

Another limitation in the use of windgaps as criteria for 
more than one cycle of erosion has recently been emphasized 
by Miller 1 who explains that windgaps may be formed by 
two streams working head ward from opposite sides of the 
same divide, developing a permanent divide between their 
heads and forming a col. Such a col could hardly be dis- 
tinguished from gaps which had once been occupied by 
streams and then abandoned. A study of the relative sizes 
and gradients of the streams on either side of the divide 
might aid in determining the histories of such gaps. 

So difficult is it to distinguish wind gaps resulting from 
piracy in the second cycle from those developed during or- 
dinary adjustment or in the establishment of permanent 
divides in the first cycle that it is doubtful if they would 
ever, even under the most favorable circumstances afford 
important evidence of more than one cycle, taken alone. 

Even-crested Summit Areas 
Perhaps the fact that the uppermost surfaces of some 
regions approximate planeness and that the summit divides 
all come up to a nearly uniform level, has been more gen- 
erally used as a criterion of more than one cycle of erosion 
than has any other evidence. But the principle has been 
abused. Various terms have been used in connection with 
this point, such as "even-crested hogbacks/' "even-crested 
ridges," "upland plains," "accordant summit levels," "even- 



1. Miller, A. M., "Windgaps," Science, Vol. 42 (1915), pp. 571-573. 



EROSIONAL HISTORY OF DRIFTLESS AREA 27 

crested divides," "even-crested uplands," and "even-crested 
skylines." The term "even-crested summit areas" seems 
to include every phase of the subject and to exclude inter- 
mediate plains, which might be included under some of the 
other terms and which constitutes a separate point. 

Study of the principles involved in the formation of 
topographies in which the highest elevations are flat-topped 
and have about the same altitude, shows that such even- 
crested summit areas constitute better evidence of more 
than one cycle if the rocks involved are folded or tilted or 
massive, than if they are horizontal or nearly horizontal 
strata. 

In Regions of Folded Strata: A plain which bevels fold- 
ed strata might be interpreted as recording the following 
events : (1) the folding of the strata, forming a topography 
of high relief with anticlinal ridges and synclinal troughs; 
(2) erosion of the surface until a large part is brought to 
grade, leaving the surface relatively flat; (3) uplift of the 
land relative to sea, renewed degradation by streams and 
the relatively rapid removal of the non-resistant materials, 
leaving the outcrops of the harder formations as ridges or 
hogbacks, the tops of which are remnants of the peneplain 
developed in the first cycle. 

It seems difficult to the writer to assign any other history 
than that outlined above to topographies illustrating even- 
crested summit areas in regions of folded strata. Other 
possible interpretations may be mentioned. Tarr 1 has ob- 
jected to the idea that the more or less even-crested ridges 
of the Appalachian region represent an ancient peneplain 
and points out (1) that they are by no means of a common 
level and (2) that elevations made of about equally resist- 
ant rock, starting with their summits above timberline, 
would be eroded rapidly and about equally to timberline, 
and then acquire more or less uniform levels, all in a single 
erosional cycle. It should be noted that these even-crests 
are not at timberline. Other investigators 2 have proven, 



1. Tarr, R. S.. Am. GeoL, Vol. 21, pp. 351-370. 

2. Davis, W. M., Am. Jour. Sci.. 1889, Vol. 37, p. 430 ; Willis, Bailey, Physiography 
of the United States, pp. 169-202 ; Hayes and Campbell, Nat'l Geog. Mag., Vol. 6, pp. 
65-126. 



28 IOWA STUDIES IN NATURAL HISTORY 

by the application of a combination of other evidences, that 
the Appalachian mountains have been eroded in more than 
one cycle and that at the accordant summits of the ridges 
there are remnants of a surface formed in a cycle previous 
to the present one. 

It has also been argued that mountain ridges can main- 
tain only a certain elevation because the surrounding area 
is not able to support the greater pressure which would 
operate if the ridges were higher. This is a part of the 
theory of isostasy. No discussion of this theory is in place 
here. It need only be said that the structure of the rocks 
in most areas where there are accordant summit levels is 
such as to prove that the elevations were once much higher 
than they now are and that they have been reduced by 
streams. 

It is also possible to assume, until proven otherwise, that 
accordant summit levels in a folded region are remnants of 
a plain of marine denudation. The criteria for distinguish- 
ing remnants of such a plain and remnants of a true pene- 
plain are clear. If the sea cut its way on the land for any 
considerable distance, portions of the wave-cut terrace 
would become sites of marine deposition and when the sea- 
denuded plain became land, it would be covered with marine 
sediments, which of course might be removed later. Also 
the border of an old plain of marine denudation would be 
a shoreline and erosion remnants on its surface would have 
the contour of islands. It has never been proven that plains 
of wide extent are made by this method, especially if the 
plain be inland, and no even-crested summit areas have 
ever been proven to be remnants of plains of marine de- 
nudation. 

It should not be said that even-crested summit areas in 
regions of folded strata considered alone, prove more than 
one cycle of erosion, but they afford strong corroborative 
evidence to that effect. 

In Regions of horizontal or nearly horizontal strata: Ac- 
cordant summit levels, where strata are horizontal or near- 
ly so, afford possibilities of interpretation not applicable in 



EROSIONAL HISTORY OF DRIFTLESS AREA 29 

regions of folded strata. In a previous article by the writer 1 
an upland plain in northwestern Illinois was conceived to 
be (1) an original marine plain of deposition ; (2;) a marine 
plain of erosion; (3) a structural plain; or (4) a true pene- 
plain. Only in case such upland plains can be proven to 
be true peneplains do they constitute proof of more than 
one cycle in the erosional history of a region. For the de- 
tailed discussion of the characterizing features of plains 
formed in the four ways outlined above, readers are re- 
ferred to the article cited. A plain of marine deposition 
should be parallel with the rock strata and should not have 
on its surface deposits of any sort younger than the marine 
formations which underlie it. A plain of marine erosion 
should be bordered by higher land and separated from this 
land by a shoreline. It should bevel the edges of rock for- 
mations ; its surface should contain marine deposits young- 
er than the formations which the plain bevels and any rem- 
nants which stand above it should be isle-like. A structural 
plain would be located on a resistant formation and would 
be parallel with the dip of that formation. If upland flats 
are remnants of a true peneplain, the surface represented 
by them when reconstructed should not, except in unusual 
cases, be parallel with rock structure, should be more or 
less uneven, have dendritic erosion remnants above it, and 
have fluvial deposits on its surface. There might be cases 
in which it would be impossible to determine the correct 
one of these four origins of upland plains, but if they be 
studied carefully enough and over sufficiently wide areas, 
correct interpretation should be possible. 

Recently, Martin 2 has expressed the opinion that features 
of the topography of the Driftless Area of Wisconsin, which 
have been most generally interpreted as even-crested sum- 
mit areas representing an old peneplain, can better be ex- 
plained by assuming that the topography is due to the un- 
equal erosion in a single cycle of series of unequally resist- 
ant rock formations having a slight monoclinal dip. After 
defining a cuesta as "an upland with a short steep descent, 

1. Trowbridge, A. C, Jour. GeoL, Vol. 21, pp. 731-738. 

2. Martin, Lawrence, Bull. No. 36, Wis. Geol. and Natl Hist. Surv., pp. 63-70. 



30 IOWA STUDIES IN NATURAL HISTORY 

or escarpment, on one side and a long, gentle slope on the 
other," and stating that "the gentle slope usually corres- 
ponds to the inclination or dip of slightly inclined sediment- 
ary rocks 1 ," he contends that the upland plains in the Drift- 
less Area are simply the gently sloping surfaces of cuestas. 
If this is the correct interpretation of such upland surfaces, 
(1) the slope of any individual patch of summit area should 
correspond in direction and amount with the dip of the 
rock formations, (2) each upland area should be formed 
by resistant rocks, and (3) the altitude of the summit of 
any given cuesta should depend upon the resistance of the 
rocks forming it and the length of time it had been exposed 
to erosion after the removal by streams of all overlying rock 
formations. 

Any considerable areas of summit flats now poorly 
drained and forming broad divides between present streams 
would hardly be formed in this way in a single cycle of 
erosion. If individual summit areas were found to bevel 
the edges of layers or formations, if these areas are large 
and far from present streams, if some of the rock forma- 
tions bevelled by the surfaces are non-resistant, and es- 
pecially if a surface reconstructed by filling the lowlands to 
the summit areas is found to have a uniform slope in direc- 
tion and amount, if this slope be uniformly greater or less 
than the dip of the beds, and if irregularities in rock struc- 
ture and rock resistance do not influence this surface, the 
even-crested summit areas could hardly be considered to 
be merely a series of cuestas. 

In Regions of Igneous Rocks: If massive igneous rocks 
solidified below the surface of the lithosphere be eroded in 
such a way as to leave flat-topped and accordant elevations, 
it seems that at least two cycles must have been involved 
in the history of the topography, except in cases where the 
massive rock had a flat surface to begin with. In the nor- 
mal case it would require a cycle of erosion to remove over- 
lying rocks and flatten the surface of the igneous rocks, and 



1. Op. Cit., p. 42. 



EROSION AL HISTORY OF DRIFTLESS AREA 31 

a second cycle to degrade some of the land further and leave 
the previous surface represented by the flat summit areas. 
It seems that accordant summit levels would be as strong 
evidence of more than one cycle in regions of massive igne- 
ous rocks as in regions of folded strata. 

Extrusive lava sheets and intruded sills might form flat- 
topped hills, when eroded, without offering more than a 
bare suggestion of more than one cycle of erosion. 

In any case there is an unanswerable question as to how 
flat upland surfaces must be and how nearly to a common 
level their remnants must come before weight is given to 
them as evidences of more than one cycle of erosion. Even 
in the regions which have suffered more than one cycle 
there are several causes of irregularity in the topography 
of the upland plain. In the first place most peneplains at 
the close of the first cycles are not flat. A total relief of 
several hundred feet would not be incompatible with the 
term peneplain, provided large portions of the surface had 
been brought to grade. Secondly, the surface might be 
warped, folded, tilted, or faulted as it is uplifted. Finally, 
erosion might roughen the upland surface after rejuvena- 
tion of the streams, without entirely destroying its former 
characters. The larger and flatter summit areas are, and 
the more nearly accordant they are, the more definitely can 
the term "even-crested summit areas" be applied to them, 
and the more certainly can the erosional histories of regions 
be read from them. The failure of accordance in the up- 
lands of a region could under no circumstances be taken as 
proof that the region had not been eroded in more than one 

cvcle. 

Even-crested summit areas should be used as evidence of 
more than one cycle of erosion only after complete and care- 
ful study. 

Intermediate Plains 

The term intermediate plain has not been used before as 
an evidence of more than one cycle, but the principle in- 
volved has been used extensively and to good advantage, 
without previously having been named. In the present con- 



32 



IOWA STUDIES IN NATURAL HISTORY 



nection an intermediate plain may be defined as one having 
a position intermediate between the summits of the high- 
est elevations and the bottoms of the deepest valleys (Fig. 
10). Or intermediate plains might be defined as plains 




Fig. 10. Diagrammatic section illustrating an ideal intermediate plain. 



above which stand erosion remnants and below which are 
valleys. The erosional history of such a region as is shown 
in Fig. 10, would seem to involve two cycles of erosion and 
to be somewhat as follows: (1) the formation of a land 
surface at levels at or above the present summits, (2) the 
reduction of the region and the formation of a peneplain, 

(3) the uplift of the region, rejuvenating the streams, and 

(4) the development of the valleys. This sort of topography 
seems to be and is strong evidence of more than one cycle 
of erosion, although it hardly amounts to proof. 

Plains having similar relations to erosion remnants and 
valleys might be structural. It is conceivable that streams 
might cut through soft surficial material, to a thick, hard 
formation of rock, then find further degradation retarded 
to such an extent that by processes of widening, the soft 
material might be removed over wide areas before the hard 
formation is cut through, leaving only a few remnants 
above the level of the top of the resistant formation. The 
surface in this stage might resemble a peneplain. Finally, 
the streams might sink themselves below the hard forma- 
tion and develop valleys at levels below the structural plain. 
However, it seems difficult to conceive that, even under the 
most favorable circumstances, intermediate plains of wide 
extent could be formed in this way. Rock terraces might 
be so formed, but hardly plains which spread across divides 
from valley to valley. Such structural plains, also, should 
be parallel with rock structure and everywhere located on 
rocks more resistant than their surroundings. 



EROSION AL HISTORY OF DRIFTLESS AREA 33 

Intermediate plains might be remnants of a plain of 
marine erosion, but the erosion remnants above it should 
be isle-like and its surface should contain marine deposits. 
Obviously no intermediate plain of great extent could be 
an original marine plain of deposition. Neither is it clear 
that the remnants of an intermediate plain could be the sur- 
face of a series of cuestas formed in a single cycle. If a 
rough topography were developed by streams and then the 
lowlands were filled, but not to the level of the summit 
areas, by glacial material or lava flows having a flat sur- 
face, streams might so dissect the glacial or volcanic fill as 
to leave remnants of an intermediate plain which would 
not record more than one cycle of erosion, in the usual sense 
at least. 

Fluvial Deposits on Uplands 

Where stream deposits are found occupying topographic 
positions distinctly above present stream beds, whether 
they lie on summit areas or areas of intermediate plain, on 
divides or on slopes above drainage, there is evidence that 
streams which once deposited, ceased depositing and began 
to degrade. As old streams most commonly aggrade and 
young streams degrade their beds, there is suggestion in 
such relations of deposits to stream beds, that the streams 
were once old and deposited and became young again, carv- 
ing out the valleys below the levels of the deposits. That 
is, such a relationship suggests that the land was uplifted 
after some portions at least had been brought to grade and 
that more than one erosion cycle was involved in the history 
of the topography in which such relationship exists. 

In case of upland or intermediate plains due to structure, 
streams flowing from soft material to the hard rock which 
forms the plain may be held at temporary grade on the soft 
material while degradation of the hard rock is in progress, 
and might deposit on the upstream side of the hard rock. 
Later in the same erosion cycle, when the hard formation 
has been cut through, the streams might cut down, leaving 
the deposits on the structural plain. It is hardly conceiv- 
able, however, that deposits which have had such histories 
would be found widely spread over upland surfaces. 



34 IOWA STUDIES IN NATURAL HISTORY 

It is possible for a stream not at grade to deposit, to 
shift its course slightly, and to sink its channel deeper, 
leaving its deposits in small areas as pockets or patches on 
upper slopes. Small patches of fluvial gravel or sand found 
on slopes above present drainage might be explained in this 
way, but thick fluvial deposits spread widely over upland 
flats could not be so explained. 

The application of this point is also limited by the diffi- 
culty in distinguishing fluvial deposits from marine or 
eolian or glacial or lacustrine deposits, especially after long 
exposure. 

Undoubted fluvial deposits spread widely over upland sur- 
faces would disprove that those surfaces represent plains of 
marine deposition or of marine erosion or are merely the 
tops of cuestas. They would almost or quite disprove the 
structural hypothesis for the origin of the upland plain on 
which they lie. Therefore, they constitute strong evidence 
of more than one cycle of erosion. 

Combinations 

If the analysis of each of the evidences of more than one 
cycle o{ erosion has been followed up to this point, it is 
clear that no one of these evidences, in the abstract and 
taken alone, can be said to prove more than one cycle in 
the erosional history of a region. However, the study of 
concrete cases of individual points may yield such proof. 
Some of the evidences usually assigned merely suggest more 
than one cycle of erosion if taken abstractly, but become 
strong evidence when properly restricted by the elimination 
of other possible interpretations. Others are strong evi- 
dence in the abstract, and amount to proof if properly ap- 
plied and limited. The relative values of these evidences 
are summed up in the accompanying table. 

Interrupted profile and stream terraces could hardly 
amount to more than a suggestion of more than one cycle 
of erosion unless all other possible interpretations had been 
eliminated by careful study in the field. 

So nearly impossible is it to distinguish the meanders of 
old age from other crooks in streams that intrenched mean- 



EROSION AL HISTORY OF DRIFTLESS AREA 35 

ders afford no more than a suggestion of more than one 
cycle. Associated sets of straight and crooked streams, on 
the other hand, are strong evidence of more than one cycle. 



TABLE SHOWING THE RELATIVE VALUES OF THE VARIOUS EVIDENCES OF 
MORE THAN ONE CYCLE OF EROSION IN REGIONS 



No. Name 


Proof 


Strong Evidence 

X? 
X? 


Mere Suggestion 


1 Interrupted Profile 


x 


2 Stream Terraces 




x 


3 Intrenched Meanders 






x 


4 Associated Sets of Straight 
and Crooked Streams 


~X~?~ 


X 

x 

X? 

X 

X 




5 Antecedent Streams 

6 Windgaps 


X? 

x 


7 Even-crested Summit Areas 


X 


8 Intermediate Plains 


X? 




9 Fluvial Deposits on Uplands 


X? 


x 





Those antecedent streams which can be proven to have gone 
to the final stage of stream adjustment and are not now in 
adjustment prove more than one cycle of erosion; any ante- 
cedent stream, except one in which warping has followed 
establishment of the stream course or one which is due to 
superimposition, is strong evidence of more than one cycle. 
Windgaps made by the abandonment of watergaps in the 
changing of streams from antecedent to adjusted courses 
form strong evidence and other windgaps merely suggest 
more than one cycle. Especially even-crested summit areas 
in regions of folded strata, are good evidences of more than 
one cycle of erosion, but from these ideal conditions the 
value deteriorates almost to zero in regions of horizontal 
strata or where accordance of summit areas is more im- 
aginary than real. It is believed that carefully investigated 
intermediate plains may prove more than one cycle and 
that any intermediate plain of wide extent is strong evi- 
dence. Fluvial deposits either on intermediate plains or on 
summit areas might prove more than one cycle under cer- 
tain conditions and would be valuable evidence in any case. 
It is to be noted that most of the abstract evidences have 
more weight in regions of folded strata than where strata 
are horizontal. 



36 IOWA STUDIES IN NATURAL HISTORY 

But the investigator must depend upon certain combina- 
tions of the various evidences, rather than upon single 
points, if he is to prove or disprove that given regions have 
suffered more than one cycle of erosion. It is unlikely that 
a surface which has been peneplained and then uplifted 
relative to the sea would show only one of the evidences of 
having had such a history. The sequence of events which 
involves two erosion cycles, and which gives rise to one of 
these lines of evidence, may give rise to all. If a region 
shows only one of these evidences the value of that one 
should be discounted because none of the others is shown. 
On the other hand a combination of several of these evi- 
dences in a region furnishes a progression toward definite 
conclusions which is geometrical rather than arithmetical. 

Referring again to the table above, Nos. 5, 8 and 9, all 
found together in a region, even without special analysis, 
would come near to proving more than one erosion cycle in 
the history of the surface, and if properly analyzed the com- 
bination might prove such a history beyond the possibility 
of a doubt. Similarly, proof might be obtained through the 
combinations of Nos. 4, 7 and 9; or Nos. 5, 6 and 8; or 
Nos. 4, 5 and 7; or perhaps by a combination of 8 and 9, 
or 5 and 7. Combinations of 4 and 8, 7 and 9, 4 and 6, or 
1, 4 and 7 might under certain topographic conditions af- 
ford strong evidence or even proof. Even Nos. 1 and 2 
combined might under certain circumstances be strong 
evidence of more than one cycle. 

It therefore seems clear that by distinguishing these 
various features in the topographies of regions, by the 
proper analysis of their possibilities and limitations under 
existing conditions, and by certain combinations, it is pos- 
sible to determine that (1) regions have certainly suffered 
more than one cycle of erosion, or that (2) they have prob- 
ably suffered more than one cycle, or that (3) they have 
possibly suffered more than one cycle. If careful study of 
a topography reveals no one of these evidences, or if it re- 
veals only one or two whose origin after analysis is found 
not to involve more than one cycle, it could be concluded 
that (4) the surface has probably not been eroded in more 



EROSION AL HISTORY OF DRIFTLESS AREA 37 

than one cycle. There would be cases where it would be 
entirely impossible to demonstrate that (5) the surface had 
certainly not been eroded in more than one cycle. 

If the deposits laid in a near-by sea during the erosional 
history of a land surface are available for study, evidence 
of more than one cycle of erosion on the land might be 
found in them. If a series of formations graded upward 
from conglomerate at the base through sandstone, shale, 
and limestone to another conglomerate, it would seem that 
the lower series including coarse, medium, and fine materi- 
als would correspond respectively with youth, maturity and 
old age of an erosion cycle on the land and that the upper 
conglomerate would record an uplift of the land and the 
inauguration of a youthful stage of a second cycle. 

However, such gradations in marine sediments might be 
due to gradually changing climates, changing depth of 
water without affecting land and sea relations, or slightly 
migrating shorelines which do not materially effect the 
height of land relative to sea. 

Alternation of sediments might be used to good advantage 
in some cases to check the topographic evidences of erosion 
cycles. For instance, the Cretaceous and Tertiary deposits 
of the Atlantic Coastal Plain should and do, at least rough- 
ly, check in this way the erosional history of the Appala- 
chian mountains as stated by Willis, Hayes and Campbell, 
and Davis. Similarly it is believed that the Tertiary and 
Quaternary deposits of the Gulf Coastal Plain of Texas will 
help in interpreting the erosional history of the Cordillera. 

MORE THAN TWO CYCLES 

When it has been demonstrated that the erosional history 
of a given surface has involved more than one cycle, the 
question of the number of cycles arises. Theoretically the 
number of erosion cycles in a region is limited only by the 
length of time during which the surface has been subjected 
to fluvial processes and the frequency of positive diastrophic 
movements during that time. So far as geologic time and 
the frequency of land-forming diastrophic movements may 
be conjectured, there is no known limit' to the number of 



38 IOWA STUDIES IN NATURAL HISTORY 

cycles which might have effected a topography. Such 
regions as the Piedmont Plateau or portions of the Lauren- 
tian Shield, which are thought to have been land since the 
beginning of the Cambrain period, have probably been 
peneplained and uplifted many times, although the detec- 
tion of so large a number of cycles would be extremely 
difficult, if not impossible. On the ftther extreme, surfaces 
fashioned by the Wisconsin ice sheet have probably nowhere 
been eroded in more than one cycle, so short has been the 
time since the retreat of the ice. 

The number of cycles of erosion which has affected a 
given region is to be determined by the number of sets of 
evidences of more than one cycle. For instance, in the 
Appalachian mountains, even-crested summit areas, ante- 
cedent streams, windgaps, intrenched meanders, associated 
sets of straight and crooked streams, intermediate plains 
and fluvial deposits on uplands, all are in evidence, and the 
combination proves more than one cycle of erosion in the 
history of the region. Obviously, even-crested summit areas 
which are the remnants of an old peneplain, and an inter- 
mediate plain representing an old peneplain, cannot belong 
to the same set of evidences if they both occur in the same 
region. Most of the antecedent streams and some of the 
windgaps of the Appalachian region belong with the set of 
evidences represented by the even-crested summit areas, 
and most of the intrenched meanders and associated sets of 
straight and crooked streams, and all of the fluvial deposits 
are clearly correlated with the intermediate plain. There 
seem to be two sets of intrenched meanders and two sets of 
antecedent streams, one set of each related to the upper 
plain and the other set to the intermediate plain. Thus, the 
older set of evidences includes even-crested summit areas, 
antecedent streams, windgaps and intrenched meanders, 
and the younger set consists of intermediate plain, fluvial 
deposits on divides, intrenched meanders, associated sets of 
straight and crooked streams, antecedent streams and wind- 
gaps. "Each of these sets includes the proper combination 
of evidences to prove more than one cycle, hence it is con- 
cluded that the region is now in its third cycle, the first set 



EROSION AL HISTORY OF DRIFTLESS AREA 39 

of evidences being proof of the first cycle, the second set 
proving that there was a second cycle carried to a late 
stage. The evidence of the beginning of the third and 
present cycle is found in the fact that the second set of 
evidences is related to a surface distinctly above the present 
streams. There are certain terrace-like features between 
the summit areas and the intermediate plain which suggest 
an additional cycle between the first and second, but as 
these benches have been proven to be structural and as 
there are no other evidences in the set, it is concluded that 
the mountains are in the third, rather than the fourth cycle. 
The method of procedure then, in determining the number 
of distinguishable cycles which have been involved in the 
erosional history of a region is as follows: (1) Determine 
how many of the evidences of more than one cycle of ero- 
sion the topography exhibits; (2) sort these evidences into 
the proper number of sets ; (3) conclude that the total num- 
ber of distinguishable cycles is the number of sets of evi- 
dences plus one. The degree of certainty with which the 
number of cycles is determined depends upon the certainty 
with which the various sets of evidences record the in- 
dividual cycles. 

THE DETERMINATION OF DIASTROPHIC EVENTS 

Because diastrophism is involved in the formation and 
renewal of lands, the interpretation of the history of land 
surfaces includes also the diastrophic history. 

The Number of Movements 

In regions in which the land surfaces were originally 
formed by diastrophism the number of positive diastrophic 
movements is the same as the number of cycles of erosion. 
For instance, the Appalachian mountains were formed first 
by folding; this is movement No. 1. Movement No. 2 in- 
terrupted the first erosion cycle and inaugurated the second 
cycle ; movement No. 3 started the third cycle. The region 
has suffered parts of three erosion cycles and there have 
been three upward diastrophic movements. 

Some surfaces, such as those formed by glaciation, by 



40 IOWA STUDIES IN NATURAL HISTORY 

lava flows, or by the draining of lakes, have no genetic rela- 
tion with diastrophism. On such surfaces the number of 
diastrophic movements is one less than the total number of 
cycles. 

The Nature of Movements 

Not only the number but the nature of diastrophic move- 
ments should be determinable in an interpretation of the 
erosional history of a region. There are several possible 
cases: (1) uniform uplift of the whole surface; (2) uplift 
with tilting ; (3) uplift with warping ; (4) uplift with fault- 
ing; (5) subsidence of the surface, with the four possible 
phases as outlined for uplift. 

Uniform Uplift: If a peneplain were formed and then 
uplifted uniformly, there would be a change in altitude but 
not in attitude. If the general slope of an old erosion sur- 
face, be its remnants on the summits or at intermediate 
levels in a topography, is approximately the same in direc- 
tion and amount as the slopes of other graded erosional sur- 
faces in the region, the inference would be that the uplift 
had been uniform. The difficulty with this point lies in 
the fact that no old erosion surface is perfectly flat, and it 
is difficult to determine whether consecutive graded surfaces 
are parallel. Also a graded plain might be uplifted uniform- 
ly and yet not be parallel with a younger peneplain if the 
streams had higher or lower gradients at the close of the 
second cycle than at the close of the first. 

However, if a peneplain represented by even-crested sum- 
mit areas is practically parallel with an intermediate plain, 
and with present valley flats on which streams are at grade, 
the conclusion would be warranted that both the uplift 
which inaugurated the second cycle and the uplift starting 
the third cycle were practically uniform. 

Uplift with Tilting: If a raised and partly dissected 
surface which was once a peneplain has a generally uni- 
form slope throughout a given region, but is not parallel 
with an intermediate peneplain or with graded streams be- 
low it, either because its angle or direction of slope is dif- 
ferent, the conditions suggest that the uplift which in- 



EROSION AL HISTORY OF DRIFTLESS AREA 41 

augurated the dissection of the upper plain was accom- 
panied by tilting. If an upland peneplain and an inter- 
mediate peneplain are essentially parallel, but are not 
parallel with an existing and undissected peneplain, the up- 
lift which started the second cycle was probably uniform 
and the movement starting the third cycle was a tilting 
movement. The best evidence of tilting in the renewal of 
lands by diastrophism is a lack of parallelism between uni- 
formly-sloping, consecutive, graded, erosion surfaces. 

As in most rules, there are limitations in the application 
of this one. Lack of parallelism between consecutive ero- 
sion surfaces, provided it is a matter of amount rather than 
direction of slope, may be due to difference in the gradients 
of final grades of the drainage system under different con- 
ditions at different times. At the close of a first cycle the 
streams may have been small and carrying heavy loads, 
with resulting high gradients and a relatively steeply slop- 
ing peneplain. The uplift may have been uniform, but in 
the second cycle larger streams carrying lighter loads may 
have developed gradients lower than those of the first cycle, 
and the two erosion surfaces would diverge upstream. By 
the reversal of the sequence, two peneplains might be 
caused to converge upstream, without tilting. 

Even differences in the direction of slope of two pene- 
plains in a region might be obtained without tilting, if con- 
ditions of structure, proximity to the sea or climate were 
so changed, during uplift, as to cause reversal or diversion 
of drainage in the second cycle. 

It is probable that these exceptions might lead to con- 
clusions that tilting has taken place where it has not in 
some cases, and that tilting has not taken place where it 
has in others. Perhaps only the more pronounced cases of 
tilting can be distinguished by this method. 

Uplift with Warping: Warping during uplift of a plane 
erosion surface would result in an irregular obliquity be- 
tween this surface and lower peneplains. The two erosion 
surfaces would converge and diverge in many directions 
and at many angles. In a region where such obliquity ex- 
ists between a summit plain and an intermediate plain, but 



42 IOWA STUDIES IN NATURAL HISTORY 

with the intermediate plain parallel with an undissected 
peneplain or with graded streams, the first recorded move- 
ment seems to have involved warping and the second up- 
lift was uniform. If the upper plain and the intermediate 
plain are parallel, but with irregular obliquity related to 
present graded streams, the first movement was uniform 
and the second one was accompanied by warping. 

This method of interpretation lacks much of being de- 
cisive. In the first place the warping or folding of an ero- 
sion surface destroys accordance of levels and makes it ex- 
tremely difficult to decide whether the surface was once 
smooth and has been warped, or whether it was never 
smooth. In the latter case there would be little evidence 
that there has ever been more than one erosion cycle. The 
warping of a surface is likely to destroy evidence that there 
has been any moveemnt at all. There would have to be some 
evidence beyond the accordance of levels to prove that the 
surface actually was a peneplain. However, such evidence 
might consist in fluvial deposits on remnants of the warped 
surface, or in antecedent streams cutting across the folds 
of the surface. 

Another difficulty with the interpretation of warping 
movements grows out of the fact that no erosion surfaces 
are altogether flat and that there is therefore an irregular 
obliquity between two consecutive surfaces whether warp- 
ing has taken place or not. However, departures from 
parallelism due to erosional irregularities in the surface 
would show themselves in topographic details and those 
due to warping would be more general ; that is, they would 
be differences between averages rather than between speci- 
fic points. Careful study of the valleys cut in the old ero- 
sion surface during the next cycle should also aid in de- 
termining whether the irregular lack of parallelism is due 
to warping or to erosional irregularities. If the valleys 
vary in depth or width or stage of development from 
point to point warping could be called in to explain such 
variations. 

After all probably the best evidence of warping of pene- 
plains is found when it is determined that the individual 



EROSION AL HISTORY OF DRIFTLESS AREA 43 

peneplain reconstructed varies in altitude above sea, that 
it has on its surface stream deposits distributed without 
reference to the variations in altitude, that the variations 
are due to flexures rather than to erosional irregularities, 
and that streams have antecedent courses at right angles 
or oblique to the flexures. 

Warping may have occurred in regions where there is 
no evidence of movement of any kind. There may also be 
suggestions of warping where uplift was uniform. There 
are doubtless regions, however, such as the Appalachian 
mountains, where warping movements have taken place and 
where, by application of the principles outlined above, mich 
movements can be proven to have taken place. These prin- 
ciples, therefore, are usable, but their use is attended with 
difficulty and may result in uncertainty. 

Uplift with Faulting: One of the best known illustra- 
tions of a cycle of erosion having been interrupted by 
faulting is found in the mountains and valleys of eastern 
California. Here an ancient erosion surface which is 
characterized by mid-Tertiary stream gravels which lie on 
the remnants of the old surface in many places, slopes up 
from low levels on the west flanks of the Sierras and reaches 
altitudes of more than 14,000 feet at the crest of the range 
where it is broken by the great fault whose scarp forms the 
east slope of the mountains. East of this line the surface 
seems to be buried under the late Tertiary and Pleistocene 
sediments of Owens Valley below altitudes of 2,000 feet. 
The surface and its gravel deposits appear again in the 
Inyo mountains east of Owens Valley, reaching altitudes 
close to 10,000 feet, where the surface is broken by another 
fault on. the east side of these mountains. The evidence of 
faulting in this case is a series of tilted blocks, each one of 
the series being sharply set off from the adjacent one by a 
fault scarp. 

It seems that cases of uplift with faulting could be cer- 
tainly interpreted only where the old erosion surface is dis- 
tinguishable in spite of great relief within short distances, 
where the separate blocks are distinct and where differences 



44 IOWA STUDIES IN NATURAL HISTORY 

in altitude of the surface are too abrupt to be accounted for 
on the basis of warping. 

Subsidence: It is a quibble whether or not the sub- 
sidence of a surface starts a new cycle of erosion. How- 
ever, the study of the erosion cycles in a region may yield 
evidence of subsidence. If it can be proven that all the 
graded streams of a region have their beds at levels far 
above beds which they previously occupied, it seems most 
likely that the surface of the region has subsided. If the 
establishment of grades below previous grades indicates up- 
lift, the establishment of new flood plains above previous 
erosional surfaces is an equally strong indication of sub- 
sidence. If uplift raises a previously graded surface above 
grade, subsidence lowers valley bottoms below the level of 
grade. 

This principle seems to be illustrated in the upper Mis- 
sissippi valley region, where the Mississippi river and its 
main tributaries are at grade 100 feet or more above the 
bedrock beneath. The fills in this region consist of glacial 
and fluvio-glacial drift. It seems likely that the surface 
subsided after the deep valleys were cut. 

Another possible interpretation is that the streams were 
not so heavily loaded before the filling as now, or were 
larger then than now, and consequently were able to reduce 
their valleys to a lower depth limit in relation to the Gulf 
of Mexico than is possible now. 

By the application of the principles outlined above for 
uplift, it might be determined whether subsidence was uni- 
form or was accompanied by tilting, warping or faulting. 

The Amount of Movement 
The interpretation of erosional histories furnishes some 
basis for determination of the amount of each diastrophic 
movement. Streams which have reached their depth limits 
in a first cycle of erosion may degrade their beds below 
these old graded levels in the second cycle by approximate- 
ly the amount of the uplift which rejuvenated them. The 
difference in altitude between two consecutive graded sur- 
faces, therefore, is roughly the measure of the amount of 
the uplift which interrupted the one cycle and started the 



EROSIONAL HISTORY OF DRIFTLESS AREA 45 

other. In a region in which there is a summit peneplain 
at 2,000 feet, an intermediate peneplain at 1,000 feet and 
graded flats at 500 feet, it could be inferred that there had 
been an uplift of approximately 1,000 feet, and a second 
one of about 500 feet. 

This method of interpretation seems simple enough but 
its application to field conditions involves possibilities of 
error. Differences in altitude between remnants of con- 
secutive graded plains vary from point to point in any 
region, (1) if uplift was accompanied by tilting, warping, 
or faulting, (2) if either surface was irregular, (3) if final 
grades differed because of changes in volume or load of the 
streams. These being common conditions, it seems pos- 
sible to get accurate figures on the amount of uplift for 
individual districts only, and even this is subject to error. 
For whole regions, only approximate averages are possible. 

THE DETERMINATION OF DATES 

The complete history of a surface involves dates as well 
as events and sequences. Various criteria have been used 
for the determination of the geologic dates of the various 
events in the histories of land surfaces. Some of these 
criteria are readily applicable and accurate if properly ap- 
plied. Others are not so valuable. The problem involves 
the ages of old erosion surfaces, the dates of diastrophic 
movements, the duration of time involved in erosion cycles, 
etc. 

The Age of Old Erosion Surfaces 

It has been customary in designating the ages of raised 
peneplains to refer to the date at which the plain was com- 
pleted and still intact rather than the whole time during 
which it was in process of formation. For instance, the 
Kittatinney peneplain in the northern Appalachians is re- 
ferred to as the Cretaceous plain, not because its formation 
was accomplished during the Cretaceous period only, but 
because it was believed to have been completed during that 
period. The cycle during which it was formed was prob- 
ably inaugurated long before the Cretaceous. Although 
this departs in a way from the usage of time terms in rela- 



46 IOWA STUDIES IN NATURAL HISTORY 

tion to rock formations, with this statement, the writer con- 
siders it best to continue the custom. 

Various methods may be used in determining the periods 
or epochs to which certain raised peneplains belong, the 
method used depending upon the conditions existing in the 
region under investigation. Some of these methods are 
here mentioned: (1) Any graded erosion surface is 
younger than the youngest formation which it cuts, and 
(2) younger than any structure it bevels. The youngest 
system forming the oldest peneplain surface in the Appa- 
lachian mountains is the Pennsylvanian, and the folds and 
faults across which the surface is developed took place in 
the Permian. The peneplain is therefore not only post- 
Pennsylvanian, but is post-Permian. (3) An old erosion 
surface is younger than any formation of which there are 
distinguishable fragments or fossils in fluvial deposits on 
the surface. This is illustrated in the Driftless Area where 
stream gravels containing chert pebbles and fossils of 
Niagaran age lie on divides where the uppermost rock is 
pre-Niagaran ; the divides must be remnants of a surface 
which is at least younger than mid-Silurian. (4) Pene- 
plains are contemporaneous with fluvial deposits which lie 
on them, (5) contemporaneous with or older than other 
terrestrial deposits lying on them, and (6) older than 
marine formations lying on them. Peneplains are (7) old- 
er than valleys which have been cut below them. An old 
peneplain is (8) younger than rocks forming erosion rem- 
nants above the plain and (9) older than deposits in valleys 
below it. A peneplain is (10) younger than any adjacent 
peneplain which stands at a higher level and (11) older 
than any lower adjacent graded plain. In the case where 
subsidence has taken place and streams have been caused 
to develop grades at levels higher than was possible before 
subsidence occurred, points (10) and (11) would be re- 
versed. The higher of two graded surfaces in this case 
would be the younger. The lower one would be buried and 
would only in the rarest case be distinguishable. (12) If 
an erosion surface has been uplifted by tilting, warping, 
folding or faulting, and there are deposits which have not 



EROSION AL HISTORY OF DRIFTLESS AREA 47 

been disturbed, the surface is older than those deposits. 
(13) A less accurate method has been used in determining 
the ages of old erosion surfaces. It has been concluded 
that a given peneplain is Cretaceous because it is known to 
be post-Triassic, and because its formation is assumed to 
have required all the Jurassic, Comanchean, and Cretaceous 
periods. Or it might be stated that a peneplain is of Eocene 
age because Pliocene deposits lie in valleys below it and it 
would have taken the Oligocene and Miocene periods to cut 
the valleys. The inaccuracy in such criteria is due to the 
varying rates of degradation by streams under varying 
conditions and to a general lack of knowledge of the dura- 
tion of the various geologic periods. 

Not all of the above-mentioned means of determining the 
ages of raised peneplains are likely to be applicable in any 
one region, but it seems that among so large a number of 
possible criteria, enough would be usable to lead to con- 
clusions giving at least the approximate age of an old ero- 
sion surface. 

Once tne age of an upland plain is established it may be- 
come a valuable horizon marker by which the ages of 
associated topographies and deposits and structures may 
be determined. If a peneplain known to be of mid-Eocene 
age is uplifted uniformly and partly dissected, all topogra- 
phies and deposits which lie above it are early Eocene or 
pre-Eocene and all topographies and deposits lying strati- 
graphically below it are late Eocene or post-Eocene. Simi- 
larly, structures which the plain bevels are pre-Eocene and 
structures in which the surface of the plain itself is in- 
volved are late Eocene or post-Eocene. 

The extreme care with which all these points should be 
used and the difficulties in the way of accurate interpreta- 
tion are emphasized in the discussion among Umpleby, At- 
wood, Blackwelder and Rich, references to which were giv- 
en on page 8. 

The Dates of Movement 
The dates of diastrophic movements in the erosional his- 
tories of surfaces can be determined in a general way at 



48 IOWA STUDIES IN NATURAL HISTORY 

least from the ages of the different erosional surfaces. For 
instance, if it has been proven that an upland peneplain in 
a given district is Cretaceous in age and there is an inter- 
mediate plain below it which is Eocene, it is a short and 
simple step to the conclusion that the uplift of the upper 
plain took place at or near the close of the Cretaceous 
period. But if two consecutive erosion surfaces are more 
widely different in age, as late Cretaceous and early Pleis- 
tocene, the uplift of the Cretaceous plain may have taken 
place at any time between the two periods; that is at the 
end of the Cretaceous, or during or at the end of the 
Eocene, Oligocene, Miocene or Pliocene. 

In such cases as the last the student is likely to fall back 
on an estimate of the amount of time it must have taken 
to produce the second plain after the uplift of the first. If 
it seems that it would have required the Miocene and Pli- 
ocene periods to produce the lower plain, it might be as- 
sumed that the uplift took place at the end of the Oligocene, 
but this assumption would not be without possibility of 
serious error. If the conclusion was reached that the up- 
lift of the older plain did take place at the close of the 
Oligocene, this plain would probably thereafter be called 
the Oligocene rather than the Cretaceous plain, for the 
period name given it would be that designating the latest 
period at which the plain is believed to have been intact. 

The conclusion arrived at is that the dates of diastrophic 
movement can be told in a general way from the ages of 
consecutive erosion surfaces, but that the closer together 
the surfaces are in age the more accurately can the date of 
the diastrophism be determined. 

Duration of Geologic Time 
A rough estimate of the duration of certain geologic 
periods might be made if the ages of consecutive erosion 
surfaces and the dates of uplift are known. For instance, 
if an upland plain with remnants at an average altitude of 
2,000 feet is of Miocene age and is known to have been up- 
lifted at the end of the Miocene period, and if in the same 
district there is an intermediate plain of early Pleistocene 



EROSION AL HISTORY OF DRIFTLESS AREA 49 

age at an average altitude of 1,000 feet, the conclusion is 
warranted that the land was degraded 1,000 feet during the 
Pliocene period. If it be assumed that all this degradation 
took place at a rate which is average for all lands through 
all times and that this average rate is 1 foot in 9,000 years, 
the duration of the Pliocene period would be estimated at 
9,000,000 years. The estimate, of course, would be subject 
to large error in each of the two points of the assumption. 
However, this method of estimating the duration of geologic 
time, duly considered and qualified, might be as accurate 
as estimates based on the rate of accumulation of sediments, 
the rate of increase of salinity in the sea, the rate of life 
evolution, or the rate of radio-active changes. 

CONCLUSION 

From the foregoing discussions it seems clear that there 
are many rules for determination of the various events in 
the erosional histories of regions, that all of them are open 
to exception and some of them to serious and frequent ex- 
ceptions, that the full interpretation of erosional history is 
attended with great difficulty, that such interpretation is 
safe only after wide areas have been studied closely, and 
with all criteria and limitations in mind, but that on the 
whole fairly accurate conclusions may be drawn by the stu- 
dent of diligence, persistence and analytic mind. 



PART II 

MESOZOIC AND CENOZOIC HISTORY 

OF THE DRIFTLESS AREA 



CONTENTS 

Page 

Acknowledgements ----------- 56 

Rock Formations ----- 57 

Structure -------------- 58 

The Stage of Erosion ---------- 60 

Evidences of More Than One Cycle of Erosion - 60 

Even-crested Summit Areas (the Dodgeville Plain) 60 

The Cuesta-single Cycle Theory ------ 69 

The Peneplain Theory --------- 79 

Intermediate Plain (the Lancaster Plain) - - - 84 

Antecedent Streams ----- 95 

Mississippi River ----- 97 

Other Streams ----------- 104 

Intrenched Meanders 105 

Associated Sets of Crooked and Straight Streams - 108 

Stream Terraces - --- __- 109 

Upland Fluvial Deposits (High Level Gravels), - - 111 

Conclusion --- _- 113 

The Number of Erosion Cycles ------- 115 

The History of Diastrophism ------- 116 

The Dates of Events 120 

The Age of the Dodgeville Plain ------ 121 

The Age of the Lancaster Plain 123 

Summary of Events _.-._ 125 



PART II 

MESOZOIC AND CENOZOIC HISTORY 
OF THE DRIFTLESS AREA 

In Part I the various principles involved in the erosional 
histories of regions were outlined and each principle was 
analyzed, without special reference to any given region. 
In Part II it seems possible to summarize and emphasize 
the principles discussed in Part I and at the same time to 
contribute something to the history of a region in which 
much work has been done, on which much has been written, 
but concerning which there has been some difference of 
opinion. 

All who have worked in the Driftless Area within recent 
years have noticed that many of the divides within small 
districts are roughly accordant in level. Most students of 
the region have concluded that the even-topped divides are 
remnants of raised peneplains and that more than one cycle 
was involved in the erosional history of the surface 1 . There 



1. Bain, H. F., "Zinc and Lead Deposits of Northwestern Illinois," Bull. U. S. Geol. 
Surv., No. 246, pp. 13-16. 

Calvin, Samuel, "Geology of Allamakee County." la. Geol. Surv., Vol. IV, pp. 41-44. 
Grant, U. S. and Burchard, E. F., Lancaster-Mineral Point Folio, U. S. Geol." Surv., 
pp. 1 and 2. 

Hershey, O. H., "The Physiographic Development of the Upper Mississippi Valley," 
Am. Geol., Vol. 20, pp. 246-268. 

Howell, J. V., "The Occurrence and Origin of the Iron Ores of Iron Hill, near 
Waukon, Iowa," la. Geol. Surv., Vol. XXV, pp. 54-62. 

Hughes. U. B., "A Correlation of the Peneplains of the Driftless Area," Proc. la. 
Acad. Sci., Vol. 23, pp. 125-132. 

Leonard, A. G., "Geology of Clayton County," la. Geol. Surv., Vol. XVI, pp. 220-233. 
MacClintock, Paul, The Wisconsin River Valley Below Prairie du Sac, Unpublished 
paper. 

Salisbury, R. D., "Preglacial Gravels on the Quartzite Range near Baraboo, Wiscon- 
sin," Jour. Geol., Vol. Ill, pp. 655-667. 

Salisbury, R. D. and Atwood, W. W., "The Geography of the Region about Devils 
Lake and the Dalles of Wisconsin," Bull. No. 5. Wis. Geol. and Nat'l Surv., pp. 60-64. 
Shaw, E. W. and Trowbridge, A. C., "Galena-Elizabeth Folio," U. S. Geol. Surv., 
pp. 9 and 10. 

Shipton, W. D., "The Geology of the Sparta Quadrangle, Wisconsin," Master's Thesis, 
Univ. of Iowa, unpublished. 

Trowbridge, A. C, "Some Partly Dissected Plains in Jo Daviess County, Illinois," 
Jour. Geol, Yo\. XXI, pp. 731-742. 

"Preliminary Report on Geological Work in Northeastern Iowa," Proc. of the la. 
Acad. Sci., Vol. 21, pp. 205-209. 

"Physiographic Studies in the Driftless Area," Abstract, Bull. Geol. Soc. Am., Vol. 
26. p. 76. 

"The History of Devil's Lake, Wisconsin," Jour. Geol., Vol. XXV, pp. 344-372. 
Trowbridge, A. C. and Shaw, E. W„ "Geology and Geography of the Galena and 
Elizabeth Quadrangles," Bull. No. 26. III. Geol. Surv., pp. 1P6-146. 

Williams, A. J., "Physiographic Studies in and around Dubuque, Iowa," Master's 
Thesis, University of Iowa, unpublished. 

55 



56 IOWA STUDIES IN NATURAL HISTORY 

has, however, been disagreement concerning the number of 
cycles, and the dates of historical events. Recently, doubt 
has been expressed that these upland surfaces represent old 
peneplains, and the belief advanced that all the features 
of tl*e topography have been formed in a single erosional 
cycle 1 . Most of the papers so far published on this sub- 
ject are the results of work done in small and isolated dis- 
tricts within the general region. Therefore it is not strange 
that agreement has not been reached, and that some of the 
conclusions are incorrect. The writer has seen all of the 
Driftless Area which lies in Iowa and Illinois and much of 
that which lies in Wisconsin and Minnesota, and it now 
seems possible to bring together material from which ac- 
curate conclusions may be drawn. 

ACKNOWLEDGEMENTS 

The writer wishes to acknowledge, with appreciation, the 
assistance of several scores of students in the Universities 
of Iowa and Chicago, who have used the Driftless Area as 
a field of instruction under his direction in the ten years 
during which he was actively engaged in teaching and re- 
search work there. Special mention is made of A. J. Wil- 
liams, Jesse V. Howell, W. D. Shipton, Urban B. Hughes, 
Leroy Patton and Paul MacClintock, each of whom has 
prepared a report on the general geology of some assigned 
portion of the Driftless area, following detailed field work. 
Most of these reports have constituted Master's or Doctor's 
theses. Not all have been published. Mr. Williams and 
Mr. Howell did their work in the Iowa portion of the 
region, Mr. Shipton in the Sparta quadrangle of Wisconsin, 
Mr. Hughes in the Richland Center quadrangle of Wiscon- 
sin, Mr. Patton chiefly in the southeastern counties of Min- 
nesota, and Mr. MacClintock along the lower Wisconsin 
river valley. In all the work special attention was given to 
stratigraphy and structure and to their relations with 
physiographic forms. The results have been freely drawn 
upon in the preparation of Part II of this paper. 

Thanks are also due to R. D. Salisbury, W. C. Alden and 



1. Martin, Lawrence, Wis. Geol. and Nat'l Hist. Surv., Bull. 36, pp. 55-70. 



EROSION AL HISTORY OF DRIFTLESS AREA 57 

Frank Leverett, who spent several days in northeastern 
Iowa with Mr. Williams and the writer in 1915, going over 
some of their data and listening with interest to some of 
their interpretations. For these interpretations, however, 
the writer assumes full responsibility. 

The previous work of Grant and Burchard in the Lan- 
caster and Mineral Point quadrangles, resulting in Folio 
No. 145 of the U. S. Geological Survey, were particularly 
useful. 

Finally to R. D. Salisbury, M. M. Leighton and Leroy 
Patton, thanks are offered for thorough criticism of the 
manuscript of Part II as well as Part I of this paper. 



ROCK FORMATIONS 
The rock formations of the Driftless Area range from 
Huronian to Silurian in age. Hard pre-Cambrian quartzite 
and igneous rocks outcrop in various places in Wisconsin, 
as at Baraboo, Wausau, Necedah, and Black River Falls 
and appear to underlie Paleozoic sediments throughout the 
area. The Paleozoic group consists of Cambrian, Ordovi- 
cian, and Silurian formations, the names, thicknesses and 
relative resistance of which are shown in the accompany- 
ing table. The Decorah shale is variable in thickness but 

TABLE SHOWING THE ROCK FORMATION OF THE DRIFTLESS AREA 



System Formation Kind of Rock 



Thickness Resistance 
in feet to erosion 



Silurian 



Niagaran 



Alexandrian 



Cherty dolomite 
Thin-bedded 
limestone 



200 Resistant 
0-80 



Nonresistant 



Maquoketa 


Shale 


100-200 


Nonresistant 


Galena 
Decorah 


Cherty dolomite 
Shale 


240 
0-30 


Resistant 
Nonresistant 


Ordovician Platteville 


Limestone 


80 


Resistant 



St. Peter_ 
Prairie du 
Chien 



Sandstone 
Cherty dolomite 



20-300 Nonresistant 



0-300 Resistant 



Cambrian 



St. Croix 
(Potsdam) 



Sandstone, lime- 
stone, shale and 
dolomite 



1000 Nonresistant 



Pre- 
Cambrian 



Quartzite, dolomite, 
slate, various 
igneous rocks 



5000+ Resistant 



58 IOWA STUDIES IN NATURAL HISTORY 

thin in all places, and, lying as it does between two resist- 
ant formations, does not affect topography greatly. So far 
as their effect on topography is concerned the Platteville 
and Galena formations are a unit. The Alexandrian for- 
mation varies in thickness and resistance and affects topo- 
graphy in such a way as to be inseparable from the Niaga- 
ran formation in some places, and from the Maquoketa in 
others. There is an unconformity between the St. Peter 
and Prairie du Chien formations, which causes both to vary 
in thickness, but the sum of their thicknesses is nowhere 
far from 300 feet 1 . The Cambrian formations are all weak 
but vary slightly in resistance. Devonian and Pennsylva- 
nian formations were perhaps deposited over part or all of 
the region, but, if 3o, they have been eroded away. The 
erosional history of the present surface started with the 
final withdrawal of the Paleozoic seas and continued 
through the Mesozoic and Cenozoic eras. 

STRUCTURE 

Although in most of the Driftless Area the strata dip in 
a general southwesterly direction, there is a northeast- 
southwest axis crossing the Mississippi river between La 
Crosse, Wisconsin, and Winona, Minnesota, and passing 
north of Sparta, north of which the beds dip northwesterly. 
In other words, the structure is that of a low anticline with 
its axis near the north edge of the region, plunging to the 
southwest, with a long limb to the south and a relatively 
shorter limb, so far as the Driftless Area is concerned, to 
the north. Most of the work on which this paper is based 
has been done south of the crest of the arch and the relation- 
ships between topographic forms and structure are con- 
sequently best known there. However, Mr. Patton and the 
writer worked in the axial area and to some extent north 
of the axis in Minnesota and Wisconsin in 1917. 

The average direction of dip of the formations south of 
Winona and Sparta, as determined by twenty-eight compu- 
tations is S. 26° W., and the average amount 14.6 feet per 



1. Trowbridge, A. C., la. Acad. Sci., Vol. XXIV, pp. 177-182. 



EROSION AL HISTORY OF DRIFTLESS AREA 59 



mile. Four computations in the area north of the arch 
show an average dip there of N. 35° W. in direction and 6.9 
feet per mile in amount. 




Fig. 11. Sketch map of the Driftless Area and its environs showing structure con- 
tours on the contact between Prairie du Chien and Jordan formations. Structural 
contour interval equals 100 feet. Horizontal scale 1/500,000. Contours are broken 
where courses are conjectural. 



60 IOWA STUDIES IN NATURAL HISTORY 

Both the south-dipping and the north-dipping monoclines 
and to an extent also the nearly horizontal structures of 
the axial area are interrupted in many places by low anti- 
clines and shallow synclines. The whole composite struc- 
ture of the Driftless Area might be said to be a low anti- 
clinorium, plunging southwestward. For additional details 
see Fig. 11. 

THE STAGE OF EROSION 

In the present cycle of erosion the general surface of the 
Driftless Area is in late youth or early maturity, although 
small portions exhibit a later stage of development. The 
valley of the Mississippi and the valleys of its larger tribu- 
taries, such as the Wisconsin, La Crosse, and Upper Iowa 
rivers, appear to be mature, but if the thick deposits in 
them were removed the valleys would have a much more 
youthful appearance. Most of the valleys in the area are 
young. There are considerable areas of unreduced flattish 
land on the highest divides and still greater areas at lower 
altitudes well above the valley bottoms. It is these unre- 
duced upland surfaces which form the chief physiographic 
problems of the region and which at the same time give the 
investigator his best clue to the history of the surface. 
Along the main drainage lines there are narrow graded 
valley flats which are valuable for comparison with the up- 
land flats. The topography has a relief of over 600 feet 
within short distances, and befor<5 the valleys were partially 
filled the relief was over 800 feet. 

EVIDENCES OF MORE THAN ONE CYCLE OF 
EROSION 

Of the several lines of evidence for more than one cycle 
of erosion which have been used in determining the erosion- 
al histories of various surfaces and which were discussed 
in Part I, the Driftless Area shows seven, in different de- 
grees of perfection and significance. 

Even-Crested Summit Areas (the Dodgeville Plain) 
In most portions of the Driftless Area the highest divides 
are noticeably flat on their summits. These flat surfaces 



EROSION AL HISTORY OF DRIFTLESS AREA 61 

forming the summit areas are the sites of cities, towns, 
villages, farms, wagon roads and railroads. In the Baraboo 
district of Wisconsin there is an area more than two square 
miles in extent so nearly flat that the drainage on its sur- 
face is poor, and no spot is 10 feet higher or lower than the 
general elevation of 1400 feet. In the southern portion of 
the Sparta Quadrangle, Wisconsin, there is much flat land 
at about 1335 feet A. T., more than 500 feet above main 
drainage lines, on which are located the villages of New- 
berg Corners, Middle Ridge and Portland (Fig. 12). Here, 




Fig. 12. View of the summit plain in the south portion of the Sparta Quadrangle. 

in an area of 5 miles square there are approximately 7,000 
acres of land under cultivation, supporting a prosperous 
population of 4,500, all on flat-topped divides. From the 
south edge of the Sparta Quadrangle a "ridge road" fol- 
lows a continuous divide for more than 50 miles, passing 
through the towns of Cashton, Rewey, Westby, Viroqua, 
Seneca and Eastman, and leaves the crest of the ridge only 
about a mile from the bluff of the Mississippi and two miles 
from Prairie du Chien. In this distance the crest of the 
divide has a relief of less than 100 feet, and the width of 
the nearly even crest varies from a few feet to a half mile 



62 IOWA STUDIES IN NATURAL HISTORY 

or more. From the main ridge tongues of flat land project 
out between tributary streams on both sides. 

In the southern portion of the Richland Center quad- 
rangle in Wisconsin the summits of many of the divides 
are nearly flat and noticeably accordant in their levels. 
These divides are spurs and outliers of a wide, continuous 
area of gently rolling land known as Military Ridge, ex- 
tending east and west in the northern part of the Lancaster 
and Mineral Point quadrangles. Military Ridge is unbroken 
from Bradtville to Blue Mounds, a distance of over 60 miles. 
On or near its summit, Bradtville, Patch Grove, Mount 
Hope, Mount Ida, Fennimore, Preston, Montfort, Cobb, Ed- 
mund, Dodgeville and Mount Horeb are located. Connect- 
ing these towns are good high roads, whose grades are low 
and on which bridges are noticeably few in number. From 
Fennimore to Blue Mounds, the ridge is utilized for the 
road bed of a branch of the Chicago and Northwestern 
Railway. 

In the north half of the Galena and Elizabeth quad- 
rangles in Illinois, the highest surfaces are the tops of 
isolated mounds or short dendritic ridges which include 
only very small patches of flat land, but which have accord- 
ant levels at about 1150 feet A. T. In the south part of 
these two quadrangles there are many long, continuous, 
dendritic, flat-topped ridges whose summit areas are the 
sites of homes, farms and ridgeroads. These ridges have 
an average altitude around 1,000 feet. At about this alti- 
tude there are thousands of acres of excellent farm land. 
In the north part of these quadrangles the summit levels 
are 450 feet above the beds of the main streams, and in the 
south part they are 350 feet above drainage. 

There are no extensive summit levels in Iowa, although 
upland plains exist. Between Waukon and Church and ex- 
tending west from Waukon toward Decorah, east through 
Lion and southeast to Rossville, there are dendritic stream 
divides whose summits are much more nearly flat than the 
surrounding surface, and are the sites of villages, main 
roads and farms. The maximum relief of this surface is 
less than 100 feet (1200-1300). Upland flats are also known 



EROSION AL HISTORY OF DRIFTLESS AREA 63 

at Monona, Luana and Watson in the southeastern part of 
the Waukon quadrangle, at National, Garnovillo, Upde- 
Graff, Colesburg, an area east of Graham, Luxemburg and 
other points in the Elkader quadrangle, and at or near 
Holy Cross, Sherrill, Rickardsville, Bankston, Balltown, 
and Tivoli in the Iowa portion of the Lancaster quadrangle. ' 
In the extreme southern part of the Driftless Area in the 
Iowa portion of the Galena quadrangle there are consider- 
able areas of flat land on high divides, which are used for 
upland farms and roads. 

Flat summit areas with accordant levels are not extensive 
in Minnesota. They are best developed in the western parts 
of Winona and Houston counties. In Winona county a 
strikingly flat plain of about 15 square miles in area lies 
between Utica and St. Charles and to the south from there. 
It is approximately 1300 feet above sea level. Near Spring 
Grove, Houston county, at an elevation of approximately 
1325 feet, the summit plain is represented by extensive 
prairie-like uplands, spurs of which ramify from the main 
area. Similar conditions occur also in the neighborhood of 
Caledonia. 

From the foregoing descriptions, the significant facts 
concerning the topography of the summit surfaces in the 
Driftless Area may be summarized as follows: (1) There 
are many divides whose summits are noticeably even. (2) 
Some of these areas of upland flat are long and broad. (3) 
The various areas of upland flat have such slight irregular- 
ity in comparison with the rest of the topography that they 
are favorable sites for farming. (4) If the elevations of 
isolated summit areas in a given district be compared, they 
are found to be strikingly accordant, though not identical. 
(5) Accordant summit levels are known in practically all 
portions of the Driftless Area. (6) The districts where 
the summit plains occur are close enough together to war- 
rant correlation from one district to another; from Bara- 
boo, through the Richland Center and Mineral Point quad- 
rangles to Jo Daviess County, Illinois; from Baraboo to 
Sparta ; from Sparta through Viroqua and Prairie du Chien 
to Iowa; from Dodgeville via Bradtville to National, Iowa; 



64 IOWA STUDIES IN NATURAL HISTORY 

from Iowa into Winona and Houston counties in Minnesota ; 
from the Minnesota line in Iowa to Dubuque ; from the Ga- 
lena quadrangle in Illinois to the area south of Dubuque in 
Iowa. (7) If the several summit areas of a district be pro- 
jected until they meet, a surface is constructed which has 
a relief of something less than 200 feet. (8) If the con- 
structed summit: plains of the several districts of the Drift- 
less Area, as explained in (7) be projected across inter- 
vening areas where summit flats are wanting until they 
meet, an almost reliefless, gently south-sloping plain results 
which covers practically the whole Driftless Area. Because 
the surface so reconstructed is well represented at Dodge- 
ville, because there is at Dodgeville a large area of upland 
flat, and because, from Dodgeville the flat may be traced 
with certainty in all directions, this uppermost plain, re- 




Fig. 13. An idealized north-south section in the Driftless Area, showing the gen- 
eral relation of the Dodgeville p'ain t:> the rock formations. The upland surfaces 
are found in large areas on the resistant Prairie du Chien, Platteville, Galena, and 
Niagara formations, but are wanting on the restively nonresistant Cambrian 
sandstones, St. Peter sandstone and Maqucketa shale. 

constructed by projecting the upland flats until they meet, 
is hereafter called the Dodgeville plain. 

Topography and rock structures are so intimately and 
fundamentally related that it is always unsafe to draw im- 
portant conclusions from analysis of topography before 
these relations are understood. It is therefore necessary 
that a careful study be made of the rock formations on 
which the Dodgeville plain lies, the structure of these for- 
mations, and the relative attitudes of plain and formations, 
before interpretation of the Dodgeville plain is attempted. 
Failure to give due weight to these relationships seems to 
be responsible for certain errors of the past. 

The Dodgeville plain is underlain by different rock for- 
mations at different places. In the Baraboo district of Wis- 



EROSIONAL HISTORY OF DRIFTLESS AREA 65 





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consin it lies on Huronian quart- 
zite and in the Sparta district on 
the Prairie du Chien and St. Peter 
formations. Military Ridge and 
its spurs are capped by Galena 
dolomite, as are also the upland 
divides around Waukon in Iowa. 
South of Turkey river in Iowa, and 
south of Lancaster in Wisconsin 
and Illinois, the plain lies on Nia- 
gara dolomite. In southeastern 
Minnesota it lies for the most part 
on the Platteville formation but it 
places cuts across to St. Peter. In 
a general way the Dodgeville plain 
bevels the south-dipping forma- 
tions, lying on progressively young- 
er beds from north to south. Either 
because of a decrease in the slope 
of the plain north of the Iowa line, 
because of a change in the direc- 
tion of slope, or because the plain 
has been very slightly warped since 
its formation, its remnants are not 
greatly higher in Minnesota than 
in Iowa, and its stratigraphic posi- 
tion is somewhat but not much 
lower in Minnesota than farther 
south. It also bevels the crest of 
the arch. No remnants of the plain 
have been observed north of the 
axis and therefore it cannot be 
definitely stated that the north- 
dipping beds are also bevelled by 
it, although such is probably the 
case. It is noticeable, however, 
that only the more resistant forma- 
tions are found capping the high- 
est divides where these divides are 
flat-topped and accordant in their 



66 IOWA STUDIES IN NATURAL HISTORY 



levels. Wide areas of the plain lie on the Prairie du Chieri.. 
Galena, Platteville and Niagara formations respectively. 
The St. Peter sandstone underlies patches of the plain in 
very small areas only, and the Maquoketa formation is not 
known to form summit flats at all. In traveling from north 
to south three distinct belts are crossed, in each of which 
there are large upland remnants of the Dodgeville plain and 
between which there is none. (Figs. 13 and 14) 

Assuming that the Dodgeville plain is a geometrical 
plane, it is possible to ascertain its dip and strike if the 
relative positions and altitudes of three points on the plane 
forming a triangle are known. If the elevations of a cer- 
tain strati graphic horizon under the three points on the 
plain can be ascertained it is also a simple matter to com- 
pute the dip and strike of the strata and get the relative 
directions and amounts of dip of plain and strata (Fig. 15) . 

. Plain 1300" 
A Stratum I240 1 




C 

Plain 1250' ^ ^_: j « 4 >+ M < 

Stratum 1000* ^*^ i pla,n * zo ° 

B stratum uoo' 

Fig. 15. Diagram showing how the dip and strike of a plain and of a stratum can 
be determined if the positions and altitudes of three points are known. A, B, and C 
are three points on the surface plain at 1300, 1200, and 1250 feet respectively. On 
the line AB there is a point D at which the altitude is the same as at C, 1250'. The 
line CD is the strike of the plain. The direction of dip is obtained by constructing 
line EB at right angles to CD through B. Reading the direction of EB the dip is 
found to be S 14° E. From E to B the surface falls 50'. Scaling EB the amount 
of dip of the plane is found to be 4.4' per mile. 

Knowing the elevations of a stratigraphic horizon under points A, B, and C to 
be 1240, 1100, and 1000 feet respectively, locating the 1100' point on AC at F, BF 
becomes the strike of the strata, the dip CG is S 37° W, and the amount of dip is 
7' per mile. 

The results of 13 such computations, based on points south 
of the axis of the arch are given in the following table. 



EROSION AL HISTORY OF DRIFTLESS AREA 67 



TABLE OF RESULTS OF COMPUTATIONS OF DIP AND STRIKE OF DODGEVILLE 
PLAIN AND ROCK STRATA 







£ 


pj 




5 








«H rf 


g 


«H g 








°s 


g^ 




General Location 


Location of Points 


.2«H 

■8° 


2° 


O 


R 






U Pi 


as 


^ Pi 


S.9 






QQ 


<5Q 


fiQ 


<Q 


South part 


A-C Sec. 20 Leon Twp. 










of Sparta 


B-CSec.8 










Quadrangle 


Portland Twp. 


N57°W 


5.3' 


S59°W 


14' 


Wisconsin 


C-NC Sec. 21 

Washington Twp. 











Whole Sparta 

Quadrangle 

Wisconsin 



A- Castle Rock 
B-Middleridge 
C-SC Sec. 18 
Jefferson Twp. 



N43°W 2.6' S38°W 10.7' 



Lancaster, 
Mineral Point 
and Richland 
Center Quad- 
rangles, Wis. 


A-Fennimore 
B-Dodgeville 
C-7V2 mi. S. of 
Wyoming 


N20°W 


9.4' 


S13°W 


14.2' 


Elizabeth 

Quadrangle, 

Illinois 


A-Wc Sec 19 

Thompson Twp. 
B-Sw Sec. 31 

Woodbine Twp. 
C-Nc Sec. 33 

Stockton Twp. 


S14°W 


7.3' 


S28°W 


34.4' 


Northern 
Iowa, Waukon 
Quadrangle 


A-Waukon 

B-Church 

C-Rossvillc 


S56°E 


10.9' 


S49°E 


8.4' 


Iowa- 
Wisconsin 


A-Church 
B-Updegraff 
C-Mt. Ida 


S76°E 


1.2' 


S40°W 


17.1' 


Wisconsin- 

Iowa- 

Illinois 


A-Sparta 
B-Waukon 
C- Stockton 


S20°E 


2.9' 


S22°W 


9.1' 


Wisconsin- 
Iowa 


A-Sparta 
B -Waukon 
C-Dodgeville 


S 4°E 


1.8' 


S20°W 


9.5' 



Iowa- 

Wiseonsin- 

Illinois 


A-Waukon 
B-Mineral Point 
C- Stockton 


S21°W 


9.6' 


S18°W 


8.3' 


Wisconsin- 

Iowa- 

Illinois 


A-Sparta 

B-Bankston 

C-Stockton 


S51°E 


3.5' 


S37°W 


12.8' 



Iowa- 
Illinois 


A-Waukon 

B-Updegraff 

C-Stockton 


S86°E 


3.2' 


S32°W 16.4' 


Iowa- 
Wisconsin 


A-Waukon 

B-Dodgeville 

C-Bankston 


S 1°E 


1.8' 


S 19°W 12.9' 


Wisconsin 
Iowa 


A-Denzer 
B -Waukon 
C-Updegraff 


S29°W 


2.2' 


S12°W 10.8' 



68 IOWA STUDIES IN NATURAL HISTORY 

These computations bring out certain facts. The plain 
constructed by connecting areas of summit plains across 
intervening areas is by no means a geometrical plane, for 
it dips in different directions and by different amounts in 
different places. In small districts, widely differing re- 
sults can be obtained by taking different sets of points as 
bases for computation. Local irregularities obscure the 
general slope. If the results of all the available computa- 
tions are considered, the average slope of the plain is in 
the direction S 75° E to an amount of 4.7 feet per mile. If 
the local estimates be eliminated and only those which in- 
volve long distances be included, the effect of local irregular- 
ities is minimized and the general slope of the plain is 
found to be S 23° E, 3.3 feet to the mile. The direction and 
amount of dip of the strata are much more nearly constant 
and average S 28° W and 14.2 feet per mile recpectively. 
Nowhere are the plain and the strata parallel. The angle 
between their respective average directions of dip is 51° 
and the strata dip more than three times as steeply as the 
plain slopes. Even in small districts where upland plains 
are broad and cover a considerable distance in directions 
at right angles to the strike of the strata, the slope of the 
plain and the beds are not parallel. The lack of parallelism 
between the Dodgeville plain and the strata which under- 
lie it is expressed in the fact that progressively younger 
beds are bevelled by the plain from north to south on the 
south limb of the arch. 

As outlined in Part I such a plain as the Dodgeville plain 
is open to several possible interpretations : It might be the 
original marine plain of deposition, a plain of marine ero- 
sion, or a structural plain on a single hard stratum. The 
apparent accordance of levels might be due to the erosion 
in a single cycle of a surface underlain by gently south- 
dipping and unequally resistant formations, developing a 
series of somewhat even-topped cuestas whose summits 
were never parts of a plain now dissected. Or, the Dodge- 
ville plain might be a true peneplain. 

The Dodgeville plain cannot be the sea bottom uncovered 
by the withdrawal of the Paleozoic sea, for it is known that 



EROSION AL HISTORY OF DRIFTLESS AREA 69 

Niagara dolomite was deposited in this sea over the whole 
region, and the plain is directly underlain by Huronian 
rocks at Baraboo, the Prairie du Chien formation at Sparta, 
the Galena formation at Church and Waukon and on Mili- 
tary Ridge. From these portions of the surface younger 
rocks must have been eroded. Also there are monadnocks 
standing above the level of this surface at several places, 
for instance, Sauk Point in the Baraboo district, Blue 
Mounds at the east end of Military Ridge, and Sherrill and 
Sinsinawa Mounds farther south. 

Neither is the Dodgeville plain the result of marine de- 
nudation. The erosion remnants above it are not isle-like, 
nor is it bordered anywhere by shore features. A still more 
significant fact is that marine deposits, younger than the 
rock formations across the edges of which the plain is de- 
veloped, are wholly wanting on the summit surfaces of the 
region, although other deposits have been preserved there. 
It is also extremely doubtful if such broad wave-cut terraces 
have ever been developed anywhere, especially far in the 
interiors of continents. 

The theory that the Dodgeville plain was formed on the 
surface of a single especially hard formation is untenable 
for the reasons that the plain lies on different formations 
at different places, that not all the formations are resist- 
ant, and that the plain slopes southward at a considerably 
lower angle than the angle of dip of the rock formations. 

The idea that the Dodgeville plain consists of a series of 
unrelated structural plains is incoroprated in the^ theory 
that the plain is a series of cuesta tops, and this tlieory is 
next to be considered. 

The Cuesta-Single Cycle Theory 
Of the first four possible interpretations outlined above, 
the idea which has been advanced that the Dodgeville plain, 
as described on previous pages, does not exist and never did 
exist, but consists merely of a series of unrelated cuestas, 
is more probable than any of those thus far considered, and 
is to be accepted or rejected only after the most careful 
study of the field conditions. A possible source of confusion 



70 IOWA STUDIES IN NATURAL HISTORY 

should be eliminated at once by the statement that what- 
ever has been the history of the upland surfaces they do 
constitute cuestas. Martin 1 has defined a cuesta as "an up- 
land with a short, steep descent, or escarpment, on one 
side, and a long, gentle slope on the other/' The three 
belts containing areas of summit flats answer the definition 
perfectly, and they are cuestas. The problem remains, 
however, as to whether their more or less even crests, re- 
lated as they are to rock structures, could have been de- 
veloped in a single cycle of erosion. As Martin points out 
in describing cuestas, "the gentle slope usually corresponds 
to the inclination or dip of slightly-inclined sedimentary 
rocks and one resistant layer, as of limestone, may deter- 
mine the whole dip slope." 

Following this definition and description the character- 
istics of cuestas which have had a history involving only 
one erosion cycle are illustrated in Fig. 16. 




Fig. 16. Diagram illustrating the topography of the Drift'ess Area as it s K ru!d be 
if the summit areas are the back slopes of normal cuestas developed in a singe cyc.e 



of erosion. 

There are several points which seem to favor the theory 
that the upland surfaces included in the Dodgeville plain 
are merely the tops of cuestas, developed, together with the 
rest of the topography, in a single cycle of erosion. (1) 
The belts in which the upland surfaces are considerable are 
cuestas. (2) The upland surfaces are practically confined 
in their distribution to the areas of outcrop of resistant 
rock formations. (3) There are three resistant formations 
and there are three conspicuous belts containing upland 
surfaces south of the anticlinal axis. (4) In individual dis- 
tricts, and in the region as a whole, the upland surfaces 
have a general southerly slope and the strata dip generally 
south. However, these arguments are superficial, for their 

1. Martin, Lawrence, Wis. Geol. and Nat' I Hist. Survey, Bull. 36, p. 42. 



EROSION AL HISTORY OF DRIFTLESS AREA 71 

features can be explained as well on the basis of more than 
one cycle as on the basis of a single cycle. There are also 
several points now to be brought out by a more careful 
study of topography, especially in its relations with struc- 
ture, which cannot be explained on the cuesta-single cycle 
theory and are in keeping with the multiple cycle theory. 

(1) The south slopes of the upland surfaces are not 
parallel with the strata as is normal for cuestas. Compare 
figures 1 and 4. The south slopes of the Dodgeville plain 
correspond with the dip of the strata neither in direction 
nor in amount, as shown in the preceding table (p. ) . 

(2) Those portions of the Dodgeville plain which lie 
on a single rock formation bevel the layers of that forma- 
tion. Within the bounds of the Sparta quadrangle, the 
summit of the Prairie du Chien cuesta lies on 35 feet of 
Prairie du Chien dolomite at Castle Rock, and on constant- 
ly increasing thicknesses to the south, until 229 feet of the 
formation appear below the cuesta top in the southwest 
corner of the quadrangle. In the Galena and Elizabeth 
quadrangles in Illinois the surface of the Niagara cuesta 
cuts from a strati graphic position 60 feet abdve the base 
of the Niagara formation at the north border of the quad- 
rangles to a position 170 feet above the base at the south 
edge. Likewise the summit of the Galena-Platteville cuesta 
lies 80 feet above the base of the Platteville limestone near 
its northern edge in the Richland Center quadrangle and 
300 feet above this horizon on one of the south spurs of 
M ilitary Ridge. This bevelling of different beds in forma- 
tions by individual cuesta tops is also illustrated between 
Church and Rossville, and between Updegraff and Monona 
in Iowa, and at many other localities within the Driftless 
Area. 

(3) In some places at least, two belts of cuesta tops 
which are roughly parallel with the strike of the strata, are 
connected by long, continuous, more or less broad summit 
divides which are roughly parallel with the dip. Such a 
divide is that connecting the Prairie du Chien cuesta in the 
south portion of the Sparta quadrangle with the Galena 



72 IOWA STUDIES IN NATURAL HISTORY 



ft"o; 



«> 



•5g 



■g* 



<J2 



cuesta east of Prairie du Chien. 
This divide includes much flat 
land on its summit. Its sum- 
mit area has a relief of less 
than 100 feet, and yet it bevels 
the edges of the Prairie du 
Chien, St. Peter, Platteville, 
Decorah, and Galena forma- 
tions. In its extent of over 50 
miles its surface falls from 
1300 feet at its north end, to 
1200 feet near Prairie du 
Chien, although a stratigraphic 
horizon which has an altitude 
of 1200 feet in the Sparta 
quadrangle is found at 620 feet 
at the south terminus of the 
divide. So independent are the 
surface and the strata that the 
change from one formation to 
another is not expressed in the 
surface. (Fig. 17) It would 
be impossible to explain the de- 
tails of such a ridge on the 
basis of a single cycle of 
erosion. 

(4) In areas where the sum- 
mit plains are broad and flat, 
and such conditions exist in 
many places in the Driftless 
Area, it is difficult to conceive 
a way by which the material 
from above was removed to 
make the flats, under the 
theory that there has been but 
one cycle of erosion. In the 
Sparta quadrangle, 200 feet 
of Niagara dolomite, 100 feet 
of Maquoketa shale, 320 feet of 
Galena dolomite and Platte- 



EROSION AL HISTORY OF DRIFTLESS AREA 73 

ville limestone, 100 feet of St. Peter sandstone, and 
many feet of Prairie du Chien dolomite have been removed 
in such a way as to leave thousands of acres of flat land 
on the divides, 500 feet above present drainage. The three 
dolomites are cherty and resistant to mechanical wear, al- 
though much of the rock is soluble in water. The sandstone 
and shale are non-resistant physically, but resistant 
chemically. These same rock formations, in varying 
amounts, have been removed in making all of the many 
upland flats of the Driftless Area. On few of these flat 
surfaces is there any concentration of residual materials 
such as chert fragments, save those which have been round- 
ed by stream action, although such residual materials are 
not entirely lacking everywhere. It seems that the removal 
of the rocks from positions above the flat upland surfaces 
must have been accomplished by some agent which was 
capable of removing products of disintegration and of de- 
composition, even the coarse material. If these surfaces 
have always been divides, and this must have been the case 
if there has been no rejuvenation of streams, all of the 
originally overlying material could not have been removed 
by streams, for on many of the flats there are now no 
streams nor stream channels. It is not conceivable that 
wind degraded the tops of the divides to make flat summits ; 
the region has not been glaciated; waves and currents have 
been eliminated. It cannot be that solution by ground 
water has been the method of degradation of these sur- 
faces, for much of the material such as shale, the sand- 
stone, and the chert in the dolomite are practically in- 
soluble. Even if it be conceived that the shale and sand- 
stone constituents were removed by the wind and the 
soluble portions of all the rocks were dissolved and carried 
away by ground water, there would be left many feet of 
residual chert. 

(5) It has been made clear that the Dodgeville plain, 
constructed by joining the various patches of summit plain 
in each of the three cuestas and the summits of the cuestas 
across intervening areas, is by no means perfectly flat. 
But, it is difficult to explain even the rough accordance of 
summit levels in individual districts and the general slope 



74 IOWA STUDIES IN NATURAL HISTORY 



of the plain southward, on the assumption that the upland 
surfaces are merely parts of unrelated cuestas. Estimat- 
ing that erosion started when the whole region was covered 
by 1000 feet of strata now gone, and knowing the amount 
and direction of dip of the strata and the elevation of the 
various portions of the summit plain, it is possible to es- 
timate what was the original altitude of the surface and to 
what altitude the upland surface was reduced at any given 
locality. The dip of the strata is so slight that the altitude 
of the original surface may be obtained by adding the 
thickness of the strata removed to the present altitude of 
the surface, without appreciable error. The results of a 
series of such computations for a series of localities from 
north to south and including each of the three cuestas south 
of the structural axis are tabulated as follows : 

TABLE SHOWING THE RELATION OF THE ORIGINAL SURFACE OF THE DRIFT- 
LESS AREA TO THE SURFACE OF THE DODGEVILLE PLAIN 



Locality 


Original 


Thickness of Total thick- 


Altitude 




altitude 


various form- ness of rocks 


of present 




of surface. 


ations re- removed in 


upland 






moved in feet. 


feet. 


surface. 


First Series- 


-Sparta-Lancaster Quadrangle 




Castle Rock 




200-Niagara 






north part 




100-Maquoketa 






Sparta 


2220 


240-Galena 


885 


1335 


Quadrangle 




80-Platteville 
100- St, Peter 
165-Prairie du Chien 






Near Portland 




200-Niagara 






south part 




100-Maquoketa 






Sparta 


2130 


240-Galena 


760 


1370 


Quadrangle 




80-Platteville 
100-St. Peter 










40-Prairie du Chien 






Near Mt. Hope, 




200-Niagara 






north part 




100-Maquoketa 






Lancaster 


1600 


90-Galena 


390 


1210 


Quarangle 











Near Richards- 
ville, Iowa, 
south part 
Lancaster 
Quadrangle 



1260 130-Niagara 



130 



1130 



Second Series — Richland Center, 
Mineral Point, Elizabeth Quadrangles 



Near Highland, 
south part 
Richland Center 
Quadrangle 



1693 



200-Niagara 

100-Maquoketa 

163-Galena 



463 



1230 



% EROSION AL HISTORY OF DRIFTLESS AREA 75 



Near Montford, 
north part 
Mineral Point 
Quadrangle 



1610 



200-Niagara 

100-Maquoketa 

110-Galena 



410 



1200 



Near Platte Mds. 

west central 

part Mineral 1440 

Point Quadran gle 

Four miles south 
of Shullsburg, 
south part 
Mineral Point 
Quadrangle 



200-Niagara 
50-Maquoketa 



250 



1190 



1375 170-Niagara 



170 



1205 



Near Erie School, 
north part Eliza- 
beth Quadrangle 

Terrapin Ridge, 
south part Eliza- 
beth Quadrangle 



1260 130-Niagara 



130 



1130 



1135 



95-Niagara 



95 



1040 



Near Church, 
north part 
Waukon 
Quadrangle 



Third Series — Waukon 
Elkader Quadrangle in Iowa 
200-Niagara 
100-Maquoketa 
1766 216-Galena 



516 



1250 



Near Monona, 

south part 

Waukon 1555 

Quadrangle 

Near Updegraff, 
central part 

Elkader 1200 
Quadrangle 



200-Niagara 
100-Maquoketa 
45-Galena 



345 



1210 



10-Niagara 



10 



1190 



Fourth Series — Baraboo, 
Richland Center, Lancaster Quadrangle 



Gibraltar Rock, 
central part 
Baraboo 
Quadrangle 



1870 



200-Niagara 
100-Maquoketa 
240-Galena 
80-Platteville 



620 



1250 



Six miles south 

of Hillsdale, 

southern part 1815 

Richland Center 

Quadrangle 

Near Preston, 

northeast part 

Lancaster 1610 

Quadrangle 



200-Niagara 
100-Maquoketa 
240-Galena 
5-Platteville 

200-Niagara 

100-Maquoketa 

140-Galena 



545 



440 



1270 



1170 



Three miles east 
of Bankston, 
Iowa, southeast 
part Lancaster 
Quadrangle 



1290 140-Niagara 



140 



1150 



76 



IOWA STUDIES IN NATURAL HISTORY 




These tables show 
that the original 
surface was much 
steeper than the 
present Dodgeville 
plain ; that the am- 
ounts of material 
removed from the 
divides decrease by 
a regular progres- 
sion to the south; 
that different pro- 
portions of resist- 
ant and non-resist- 
ant rocks have 
been removed in 
different places ; 
and that there is a 
certain definite or- 
der in the rela- 
tions of original 
altitudes, amount 
of rock removed, 
and present alti- 
tudes, irrespective 
of the relative 
thickness of resist- 
ant and non-resist- 
ant formations re- 
moved (Fig. 18). 
It seems improb- 
able that degrada- 
tion of the tops of 
divides would' take 
place in so orderly 
a fashion unless 
the streams re- 
duced the general 
surface to grade. 



EROSION AL HISTORY OF DRIFTLESS AREA 77 

(6) In a region where so much erosion has taken place 
it would seem that the relative hardness of the resistant 
formations would express itself in topography if there had 
been but one cycle. The most resistant of the three should 
stand the highest, and the least resistant the lowest. But 
the general southward slope of the Dodgeville plain is un- 
interrupted by differences in rock hardness, although it is 
doubtless true that local resistant rocks have influenced 
local irregularities in its surface. (Compare Fig. 16 with 
Figs. 13 and 14) 

(7), If the upland surfaces in the Driftless Area are en- 
tirely structural it would seem likely that the local anti- 
clines and synclines which interrupt the general monoclinal 
dip would cause undulations in the surface of the Dodge- 
ville plain. In the Galena and Elizabeth quadrangles, where 
a portion of this plain is well known and where the anti- 
clines and synclines have been carefully mapped, there is 
no apparent relation between the altitude of the upland 
surfaces and the folds. The plain bevels the local folds 
without any expression of the structure in the topography. 
It is true that there are a few high parts of the upland 
plain which correspond roughly with anticlines, such as at 
Waukon, but there are also many high places where there 
are no anticlines, many high places over synclines, and 
many low places on anticlines. No general effect of local 
structure can be observed in the topography of the plain. 
The higher portions of the upland plain are to be inter- 
preted as resistant portions of the rocks or as original 
inter-stream areas, not as arched structures. 

(8) It is abnormal for the divides of a surface to be 
lowered greatly before evidences of old age in adjacent 
valleys appear. During youth of the normal cycle of ero- 
sion the main work of the streams is in the development of 
valleys and the dissection of the original surface. Maturity 
is ushered in when the upper flat approaches thorough dis- 
section and lasts until lower flats are formed and come to 
constitute an appreciable portion of the surface. Most of 
the work of lowering the original divides is accomplished 



78 IOWA STUDIES IN NATURAL HISTORY 

after the old age of the valleys has been reached. Another 
principle in the normal erosional cycle is that divides are 
not degraded much, before permanent divides have been 
established, that is, before valleys have reached their width 
and length limits, that is, before the valleys have ap- 
proached or reached old age. Now the summit divides in 
the Driftless Area are known to have been degraded by 
amounts varying from 10 feet to 885 feet (see the fourth 
column from the left in the above tables), and yet the val- 
leys show few signs of old age, and few of the divides are 
permanent. If the present surface was formed in a single 
cycle of erosion, this cycle was not normal. 

(9) Assuming that but one cycle has been involved in 
the erosion of the surface of the Driftless Area, recon- 
structing the original surface by projecting the Niagara 
and older formations over portions where they do not now 
exist, and getting the altitudes of the lowest points reached 
by streams beneath the present valley fills ; it is found that 
the streams at La Crosse must have reduced their beds 
from about 2200 feet A. T. to 600 feet in order to reach 
grade; and the streams in the south portion of the Drift- 
less Area in the vicinity of Dubuque, could have become 
graded by cutting from approximately 1300 feet to 300 feet. 
The Mississippi and its tributaries should have reached 
grade at Dubuque after cutting through 1000 feet of rock 
of varying hardness long before they brought their beds to 
grade at La Crosse, where they had to cut through 1600 
feet of the same rock, and the topography around Dubuque 
should now be in a distinctly later stage of development 
than that in the neighborhood of La Crosse. But the op- 
posite is true. Due to the relative non-resistance of the 
Cambrian sandstone on which the streams have their 
courses at present in the north part of the area, there is a 
greater area of lowland there than farther south, and the 
topography around La Crosse has an appearance of greater 
age than the surface near Dubuque. 

(10) In advance of complete description and interpreta- 
tion it should be made clear here that there are in many 
places on the Dodgeville plain considerable areas of gravel 



EROSION AL HISTORY OF DRIFTLESS AREA 79 

which have undoubtedly been deposited there by streams 
which could not carry their loads all the way to the sea. 
These deposits are known near Devil's Lake, Cashton and 
Seneca in Wisconsin, and near Church, Elon and Waukon 
in Iowa, as well as at numerous other places within and 
south of the Driftless Area. This fact is not mentioned 
by Martin. It seems to the writer to be a fatal objection 
to the single cycle theory. 

The conclusion now has been reached that the Dodgeville 
plain is not an original plain of marine deposition, nor a 
plain of marine erosion, nor a simple structural plain. The 
theory that the plain consists merely of three cuestas whose 
summits were developed in the present cycle of erosion is 
untenable. 

The Peneplain Theory 

It remains to test the fifth possible interpretation. Some 
of the points in favor of the theory that the plain is an 
ancient peneplain dissected by erosion in subsequent cycles 
have been touched upon indirectly in the analysis of the 
cuesta theory. However, for the sake of definiteness and 
completeness they are listed below. 

(1) The plain includes many upland surfaces so large 
and so nearly flat that some effective agent of transporta- 
tion, such as streams, must have operated there in order to 
remove the large amount of material which originally ex- 
isted at higher levels. (2!) The plain has a slope of about 
S to 5 feet per mile in a general southeasterly direction. 
Its slope is notably different both in direction and amount 
from the dip of the strata. (3) The general southerly slope 
of the plain is obscured locally by irregularities such as old 
erosional surfaces show. Even locally the slopes of the 
plain are not parallel with rock structures. (4) The plain 
bevels the edges of rock formations irrespective of their 
hardness. (5) In the formation of the plain, thicknesses 
of rock have been removed, which decrease regularly from 
north to south, bearing evidence that some sort of a grade 
was established where the tops of the cuestas now are. 
(6) The existence of certain continuous north-south ridges 



80 IOWA STUDIES IN NATURAL HISTORY 

connecting the cucstas, such as the divide from Cashton to 
Prairie du Chien, described above (Fig. 17), seem to sug- 
gest that there was once a plain on non-resistant, as well 
as resistant material. These connecting ridges are ap- 
parently remnants of an upland surface once continuous 
across inter-cuesta areas. (7) If the Dodgeville plain is 
an old peneplain there is no necessity for conceiving that 
the divides have been reduced by hundreds of feet in a 
cycle of erosion in which the streams have scarcely reached 
grade. (8) There are distinct erosion remnants standing 
on the plain, far from present drainage lines. In some cases 
these remnants consist of material which is more resistant 
than that outcropping on the adjacent plain. In other cases 
the rock of the remnant and the rock of the plain are the 
same. There seems to be no reason why these divides 
should have been reduced in such a way as to leave rem- 
nants above their general flat surfaces, unless the streams 
reached grade at or near the levels of these surfaces. (9) 
The presence of stream deposits at many places on the plain 
not only appears as a fatal objection to the single cycle 
theory, but it seems practically to demonstrate that the 
Dodgeville plain is a raised peneplain. (10) Both Creta- 
ceous sediments west of the Driftless Area and Tertiary 
deposits to the south must have been derived at least partly 
from erosion in the Driftless Area and both bear evidence 
that the land of their sources was low and approaching the 
peneplain stage. (11) The fact that Tertiary deposits of 
the great Mississippi embayment, extending north toward 
the Driftless Area, lie in a gently sloping plain which, if 
projected, would coincide with the Dodgeville plain, is dis- 
tinctly in favor of the peneplain theory. (12) As will be 
explained more fully within the next few pages, there are 
lense 7 shaped bodies of the softer formations underlying the 
Dodgeville plain in two or three places, which show that the 
surface over them was brought to grade. (13) In addition 
there are within the Driftless Area other strong evidences 
of more than one cycle of erosion, yet to be described, which 
in combination with the even-crested summit areas increase 
the value of these upland flats as evidences and the com- 



EROSION AL HISTORY OF DRIFTLESS AREA 81 

bination demonstrates that the surface has been eroded in 
more than one cycle. 

Objections which might be advanced to the peneplain 
theory have been expressed by Martin 1 . Each objection is 
now to be considered. 

(1) Doubt is expressed if the various areas of upland 
surface making up the plain are large enough, flat enough, 
close enough together, and sufficiently accordant in their 
levels to warrant the conclusion that they are the remnants 
of a once continuous peneplain. As was brought out in 
Part I, there is no definite degree of flatness which a sur- 
face must assume before it can be called a peneplain. Also 
there are various ways in which such a surface may be 
made irregular in the second cycle. It is not believed that 
the Dodgeville plain was degraded to such extremes that 
the surface was altogether flat. There were doubtless many 
gently sloping valley walls as well as valley flats. Not all 
the tributary streams far from the main drainage lines had 
low gradients. And the facts remain that there are some 
upland surfaces which are essentially flat; that the upland 
areas are large enough and numerous enough to furnish 
thousands of acres of farm land which is notably flat ; that 
the highest recorded slope on the plain is less than 11 feet 
per mile and the average slope less than 4 feet per mile; 
and that the Dodgeville plain includes more and larger 
areas of flat land and is represented by more nearly accord- 
ant levels than the Kittatinny peneplain of the Appalachian 
mountains, the Tertiary peneplain of Idaho or the Miocene 
peneplain of the Sierra Nevadas. 

(2) Martin gives some consideration to the time in- 
volved in the erosion of the area and concludes that, al- 
though there has been sufficient time since the late Paleozoic 
for the formation of a peneplain, there has also been time 
for the destruction of such a plain. The writer does not 
see that the time involved furnishes points either in favor 
of or against the peneplain or cuesta theory. So far as the 
duration of time is concerned, several peneplains could have 
been formed and destroyed during the Mesozoic and Ceno- 

1. Martin, Lawrence, Bull. No. 26, Wis. Geol. and Nat'l Hist. Surv., pp. 64-68. 



82 IOWA STUDIES IN NATURAL HISTORY 

zoic eras. There is, however, no indication in this that some 
relatively recent peneplain, such an one completed in late 
Tertiary, could not to-day be represented by remnants. 

(3) Believing that sediments must have been derived 
from the surface of the Driftless Area in the formation of 
the Dodgeville plain, and not certainly finding such sedi- 
ments in the Devonian and Carboniferous rock adjacent to 
the Area, Martin objects to the peneplain theory. Clearly 
he is laboring under a misconception as to the age of the 
plain. Whether or not it is an old peneplain, its surface is 
much younger than the Paleozoic. All of the Paleozoic for- 
mations, including the Devonian and Carboniferous are 
known to be bevelled by the Dodgeville plain south and west 
of the Driftless Area. Most of those who have previously 
interpreted it as a peneplain have assigned it to the Creta- 
ceous and the writer will later in the paper present evidence 
for the late Tertiary age of the plain. Most likely then the 
sand, silt, and clay derived in the formation of the Dodge- 
ville plain were carried westward into the Cretaceous sea, 
or most likely southward into the Tertiary embayment. 
Indeed, both the Cretaceous and Tertiary systems contain 
materials which must have been derived from erosion in 
the Driftless and adjacent areas during these periods, and 
there is evidence that peneplanation was in progress. Thus 
by reference of the Dodgeville plain to its proper geological 
period Martin's point of objection to the peneplain theory 
is converted into an additional argument in favor of that 
theory. 

(4) It is true, as pointed out by Martin, that the Devo- 
nian and Carboniferous rocks lie on surfaces of less relief 
than that of the Driftless Area, and that this does not show 
that the peneplain of the Driftless Area is projected to lie 
beneath these sediments. However, it is not to be con- 
sidered in any way as an objection to the peneplain theory. 
The plain is clearly much younger than any Paleozoic sys- 
tem. If the Cretaceous or Tertiary sediments could be 
proven to lie on a projection of the Dodgeville plain, strong- 
evidence would be offered that it is a peneplain. The Creta- 
ceous rocks of Minnesota are bevelled by the plain and 



EROSION AL HISTORY OF DRIFTLESS AREA 83 

therefore do not lie on its projection. Salisbury 1 has pre- 
sented evidence that the plain does slope down beneath the 
Tertiary deposits of the lower Mississippi valley and that 
those deposits lie on a plain similar to and continuous with 
the Dodgeville plain in the Driftless Area. This point af- 
fords strong evidence in favor of the peneplain theory. 

(5) Martin concludes his objections to the peneplain 
theory by stating that there are no wedge-shaped bodies of 
non-resistant rock overlying the south-dipping resistant 
layers, as there should have been when the Dodgeville pene- 
plain was undissected. He agrees, however, that these 
wedges could have been removed by the rejuvenated 
streams. Their absence, therefore, is no objection to the 
peneplain theory, but is in harmony with the cuesta, as 
well as with the peneplain theory. 

As a matter of fact, btit apparently unknown to Martin, 
there are just such wedges of St. Peter sandstone north of 
the Platteville-Galena cuesta in Wisconsin, and Maquoketa 
shale north of the Niagara cuesta in Iowa. Fig. 5 affords 
an illustration of the St. Peter wedges. Other illustrations 
are found in the south part of the Richland Center quad- 
rangle, where ever-increasing thicknesses of St. Peter cap 
the north-south divides to the foot of the Platteville cuesta, 
where the full thickness of the St. Peter is represented. In 
Iowa the south rim of the valley of Turkey river, south of 
Osterdock, is underlain by a few feet of Maquoketa shale 
which dips south with the Galena dolomite below. Along: 
a road which follows a flat-topped divide southward, the 
Maquoketa gradually thickens until its full thickness is 
found at the foot of the Niagara escarpment. Martin says : 
"They (the wedge-shaped bodies) would furnish excellent 
evidence of previous baselevelling, but no such remnants 
are known to exist." Now that such lenses of non-resistant 
material have been discovered, this point is transferred 
from the unfavorable to the favorable column for the pene- 
plain theory. 

In conclusion it may be said that the summit areas in 

1. Salisbury, R. D., Bull. Geol. Soc. Am., Vol. 3, pp. 183-186, Jour. Geol., Vol III dp 
655-667. ' 



84 IOWA STUDIES IN NATURAL HISTORY 

the Driftless Area, after analysis, seem almost certainly to 
be remnants of a peneplain uplifted since its formation and 
now almost entirely destroyed by the rejuvenated streams. 
And yet demonstration of the multiple cycle theory does not 
rest on this evidence alone. It remains to be seen whether 
there are other indications of more than one cycle and 
whether there is a combination of evidence which actually 
proves the case. 

Intermediate Plain (the Lancaster plain) 
At many places in the Driftless Area there are isolated 
areas and more or less continuous surfaces, sharply set off 
from the remnants of the Dodgeville plain, but forming 
divides several hundred feet above drainage. Though 
similar in most respects to the summit surfaces, these flat- 
topped but lower divides occupy a position intermediate 
between the remnants of the Dodgeville plain and the val- 
ley bottoms. If the tops of these intermediate divides were 
projected across the valleys and across the areas where 
remnants of the Dodgeville plain exist, a plain similar to 
the Dodgeville plain would be formed, having a general 
altitude approximately 200 feet lower than the Dodgeville 
plain. This is the more conspicuous of the two upland 
plains, and is the one about which most has been written. 
Various names have been applied to this plain by differ- 
ent writers. It is Hershey's 1 plain No. 1. Grant and Bur- 
chard 2 named it the Lancaster Plain. The writer 3 called 
it the Galena Plain in Jo Daviess County, Illinois. In Iowa 
it has been called the Lower Plain or Plain No. II 4 . Ship- 
ton 5 called it the Sparta Plain and Hughes 6 assigned to it 
the name Limeridge Plain. The surface is as well developed 
in the neighborhood of Lancaster, Wisconsin, as anywhere, 
and therefore the name assigned by Grant and Burchard 
is retained for this plain. 

1. Hershey, O. H., Am. Geol.. Vol. 20, pp. 246-268. 

2. Grant, U. S. and Burchard, E. F., Lancaster-Mineral Point Folio, U. S. Geol. 
Surv., p. 2. 

3. Trowbridge, A. C, Jour. Geol., Vol. 21, pp. 739-741. 

4. Howell, J. V., Iowa Geol. Surv., Vol. 25, pp. 59-60. 

5. Shipton, W. D., Geology of the Sparta Quadrangle, unpublished thesis in library 
of University of Iowa, p. 57. 

6. Hughes, U. B., Geology of the Richland Center Quadrangle, manuscript in prep- 
aration. 



EROSION AL HISTORY OF DRIFTLESS AREA 85 

Portions of the Lancaster Plain are known in the north- 
ern part of the Sparta quadrangle at an average altitude 
of 1100 feet; in the Baraboo district at 1200 feet; in the 
northern and central portions of the Richland Center quad- 
rangle on divides sloping southward from 1200 to 1100 feet; 
in the central and southern portions of the Lancaster and 
Mineral Point quadrangles at levels varying from 1100 to 
1000 feet; in the northern and central portions of the Gale- 
na and Elizabeth quadrangles, Illinois, sloping southward 
from 1000 feet to 900 feet ; in southeastern Minnesota at al- 
titudes of about 1200 feet; and in northeastern Iowa from 
the Minnesota line at an altitude of 1100 feet to Dubuque, 
where it lies at and around 900 feet altitude. The best 
general view of the surface may be obtained from the 
Mississippi river between Bellevue, Iowa, and La Crosse. 
Along this whole extent of river the immediate rim of the 
Mississippi valley appears to be almost a horizontal line ex- 
cept where broken by tributary valleys. Nowhere does the 
Dodgeville plain come to the edge of the bluff, although, 
near Turkey river and Prairie du Chien, remnants of the 
higher plain are close enough to be visible from the river 
and appear as monadnocks standing above the plain which 
forms the rim of the valley. 

On the whole, the Lancaster plain is represented by up- 
land surfaces which are more numerous, larger, closer to- 
gether, and more nearly continuous than the summit areas 
which constitute the remnants of the Dodgeville plain. In 
the Sparta quadrangle, the Lancaster plain is represented 
by a series of narrow divides above which stand con- 
spicuous remnants of the Dodgeville plain such as Castle 
Rock and Balls Bluff. In the Baraboo district por- 
tions of the lower plain include the general flat crest of 
the North quartzite range at Ableman and at the Lower 
Narrows, broad, poorly drained divides between north flow- 
ing and south flowing, streams on the south range, and flat 
benches on the south range, such as the one at 1200 feet 2 
miles northeast of Denzer. Just north of the Wisconsin 
river the plain is best shown on the crests of north-south 
divides, such as the divides between Pine, Bear, Narrows, 



86 



IOWA STUDIES IN NATURAL HISTORY 



and Honey Creeks, on which are located the main roads of 
the district, hundreds of prosperous farms, and the villages 
of Limeridge, Sandusky, and Loreto. Wide areas of the 
plain are found at or near Blake Prairie, Diamond Grove, 
Rockville, Hurricane, Lancaster, (Fig. 19), Liberty Ridge, 



y^ 



■*d;l r , '-,'HfcJ."----V --.<"; 

*;4_;- i L^ _^_ £_ ^ , , , , ; ., , ,. t ., ~U«rffc 






5 ^ 










Fig-. 19. A portion of the Lancaster topographic map showing 
tent and distribution of the Lancaster plain in its type leca ity. 



the ex- 



Jamestown, and Cornelia in the Lancaster quadrangle, and 
near Livingston, Rewey, Belmont, Cuba, and Fayette in the 
Mineral Point quadrangle. In these two quadrangles the 
surfaces representing the Lancaster plain are long and 
broad, and are utilized extensively for various sorts of 
human activity. Most of the surfaces are north-south 
divides or east-west projections of north-south divides. 
In the Elizabeth quadrangle in Illinois there are large 
areas of this intermediate plain, the most conspicuous 
of which are south of Apple River and northwest of Stock- 
ton, (Figs. 20 and 21) , where there are surfaces lxl Yi miles 



EROSION AL HISTORY OF DRIFTLESS AREA 87 



?/ 



JX&&> 



f ,'~ 











^r^p: 






Fig-. 20. A portion of the Elizabeth topographic ir.ap where the Lancaster plain is 
exceptional. y well represented. 




*ig. 21. View of the Lancaster plain in Jo Daviess County, north of Stockton, Illi- 
nois. The elevations in tho distance are the "mounds" which are monadnocks on the 
plain. Below the general surface, there are valleys more than 200 feet deep. 



88 IOWA STUDIES IN NATURAL HISTORY 

in extent. These surfaces have maximum relief of less than 
10 feet and are poorly drained. Above them stand con- 
spicuous monadnocks, and below them are abrupt valleys 
more than 100 feet in depth. The Lancaster plain is rep- 
resented in the Galena quadrangle by the divides between 
Sinsinawa and Galena rivers, used as the site of the Hazel 
Green Pike road, and the divide between Galena River and 
Smallpox Creek. The tops of these divides consist of flat 
surfaces or gentle slopes. They average 900 feet above sea, 
300 feet above present drainage, and 150 feet below the 
tops of the mounds which stand conspicuously upon them. 
In Iowa most of the tops of the divides within eight or ten 
miles of the Mississippi River are to be correlated with the 
Lancaster plain; for instance, the divides between Upper 
Iowa River and the Minnesota line, between Clear Creek 
and Village Creek, Village Creek and Paint Creek, Paint 
Creek and Yellow River, Yellow River and Bloody Run, 
Bloody Run and Sny Magill Creek, the divides north and 
south of Yellow River, etc. (Figs. 22 and 26). The plain 




Fig. 22. View of the Lancaster plain and the gorges below it, as seen near Waukon 
Junction, Iowa. 

is also represented in the vicinity of Dubuque. The Lan- 
caster plain in the Minnesota portion of the Driftless Area 



EROSION AL HISTORY OF DRIFTLESS AREA 89 

forms gently rolling intermediate surfaces, so extensive and 
so nearly flat as to be known locally as "prairies." Areas 
representing the plain here are known south of Preston and 
in other portions of Fillmore county, in Houston county 
south of Root river near Caledonia, in nearly all parts of 
Winona county and in the southeastern portion of Wabasha 
county. Though the areas are most extensive away from 
the Mississippi river, representatives of it are known right 
to the edge of the river gorge. 

As in the case of the Dodgeville plain, the Lancaster 
plain lies on different rock formations at different places. 
North of the Prairie du Chien cuesta in Wisconsin it lies 
on the Cambrian sandstone, in Minnesota on Platteville, St. 
Peter and Prairie du Chien, south of the Prairie du Chien 
cuesta on the Prairie du Chien and St. Peter formations, 
south of the Platteville-Galena cuesta on the Galena and 
Maquoketa formations. In general, the farther north a 
portion of the plain is the older the formation, and the low- 
er the part of the formation on which it lies. Progressively 
younger rocks are bevelled by the plain toward the south. 

The Lancaster plain slopes in a general southerly direc- 
tion at an angle less than the angle of dip of the strata. 
The details in the relations of the plain and the structure 
south of the anticlinal axis are shown in the table on page 
90. 

The computations, the results of which appear in the 
table, show that there is a marked parallelism of plain and 
strata in several of the individual districts, such as the 
Richland Center, Sparta and Mineral Point quadrangles, 
but that in other districts and where greater distances are 
involved, this parallelism fails. It is notable that all the 
local estimates show the intermediate surface sloping in 
directions west of south, which is the direction of dip of 
the strata and that those estimates including more widely 
separated points on the plain show a general slope east of 
south. Considering only the local districts the plain appears 
to have an average slope of 10.9 feet per mile in the direc- 
tion S 17°W and the strata dip S 28°W at an angle of 16.6 
feet per mile. Over the larger areas the average direction 



90 



IOWA STUDIES IN NATURAL HISTORY 



TABLE OF RESULTS OF COMPUTATION OF DIP AND STRIKE OF LANCASTER 
PLAIN AND ROCK STRATA 



General Location 



North part 
Richland Center 
Quadrangle 



North part 

Sparta 

Quadrangle 



Lancaster 
Quadrangle 



Mineral Point 
Quadrangle 

Galena 
Quadrangle 



Elizabeth 
Quadrangle 



Waukon 
Quadrangle 
in Iowa 



Iowa- 
Wisconsin 



Wisconsin- 

Iowa- 

Illinois 



Wisconsin- 
Iowli 

Wisconsin- 
Iowa 

Wisconsin- 

Jowa- 

Illinois 



Location of Points 



GT5 



2 O O 

la* 



-p 

3 o « 
o ft 

6 .& : 



A-Limeridge 
B-3% miles 
south Loreta 
C-2V 2 miles N.E. 
Richland Center 
A-l mile south 
of Castle Rock 
B-Center Sec. 3 

Burns Twp. 
C-W. C. Sec. 23 

Burns Twp. 



A-Blake Prairie 
B-Lancaster 
C-Near Jamestown 
A-Rewey 
B-Cuba 

C-Fayette 

A-S. Sec. 24 

Vinegar Hill Twp. 
B-Galena 
C-N. E. Sec. 23 

Galena Twp. 

~~A-Foot of " 
Hudson Mound 
B-Warren 
C-C Sec. 9 Rush Twp. 

"A-4%mi.W.of 
New Albin 
B-3 mi. S. E. 
of Lansing 
C-3 mi. S. E. 
of Watson 



A-Near New Albin 
B-Near Watson 
C-Near Bloomington 
A-Near Sparta 
B-Near New Albin 
C-Near Stockton 



A-Near Sparta 
B-Near Bloomington 
C-Near New Albin 
A-Near Denzer 
B-Near Bloomington 

C-Near New Albin 

A-Near Loreta 
B-Near Watson 
C-Near Stockton 



S25°W 7.6 S15°W 7.6 



S80°W 12.5 S59°W 14. 



S26°W 8.9 S29°W 34. 



S 9°W 7.3 S 9°W 9.1 



S46°W 27.2 S13°W 13.9 



S 8°W 8. S20°W 9.8 



S77°E 5.1 S51°W 27.6 



S42°E 2.1 S22°W 15. 

N89°E 3.1 S 7°W 9.4 

^S 82°E 4. S 9~A 

S16°W 2.8 S11°W 11. 



S 1°E 3. S19°W 11.6 



EROSION AL HISTORY OF DRIFTLESS AREA 91 

of slope of the plain is S 40 °E and the average amount of 
slope 3 feet per mile, while the corresponding figures for 
the strata are S 12°W and 11.3 feet. Including the results 
of all the estimates, both local and general, the plain slopes 
S 11°E to an amount of 7.6 feet to the mile and the strata 
dip S. 20°W, 14.4 feet per mile. The plain and the strata 
fail of parallelism by 31° in direction and 6.8 feet per mile 
in dip. 

In the literature of the subject the Lancaster plain and 
the Dodgeville plain have in some cases been confused; in- 
deed there has been some doubt expressed that they are 
really distinct. In his criticisms of the peneplain theory to 
explain the accordant divides of the Driftless Area, Mar- 
tin 1 assumes two cases: (1) that there are four upland 
plains, one for each cuesta, and (2). that there is but one 
upland plain. He does not consider the problem of two up- 
land plains and appears to believe that all the upland sur- 
faces form a single plain, if indeed they may be said to 
form plains at all. This confusion doubtless grows out of 
the fact that there are places where the summit plain only 
is found and places where only the intermediate plain oc- 
curs. In such latter places the Lancaster plain could easily 
be mistaken for a summit plain. There are also some local- 
ities within the Driftless Area in which both plains occur 
and where they appear to grade into each other. 

And yet the summit plain and the intermediate plains 
are distinct. The evidences are as follows: (1) In most 
portions of the Driftless Area, as between Waukon and the 
Mississippi river (Fig. 23), and in the district south of 
Turkey river in Iowa, in the Galena and Elizabeth quad- 
rangles in Illinois, in the northern and central portions of 
the Lancaster and Mineral Point quadrangles, in the Rich- 
land Center quadrangle, in the Baraboo district and in the 
Sparta quadrangle in Wisconsin, and in Minnesota both 
plains are found and in most of these places the lower 
plain is so sharply set off from the upper one that the two 
can be distinctly seen in any general view. (2) Even in 
districts where intermediate levels seem to grade into sum- 

1. Martin, Lawrence, Bull. No. 36, Wis. Geol. and Nat'l Hist. Surv., pp. 66-67. 



92 IOWA STUDIES IN NATURAL HISTORY 

mit levels, careful inspection brings out distinct differences 
in altitude between the two plains. For instance, the Lan- 
caster plain around Lancaster, seems, on casual observa- 
tion, to grade into the Dodgeville plain on the summit of 





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Fig. 23. View east of Waukon, Iowa, showing both the Dodgeville and Lancaster 
plains. The picture was taken from the Dodgeville plain which shows in the fore- 
ground and forms the skyline. The general topography which forms the rims of the 
valleys in the middle distance is the Lancaster plain. 

Military Ridge. Grant and Burchard 1 included Military 
Ridge and the area around Dodgeville with the Lancaster 
plain. However, there are many views obtainable in which 
Military Ridge stands distinctly above the intermediate 
levels and carefully drawn profiles show the two plains to 
be distinct 2 (Fig. 24). (3) Where both plains are repre- 
sented in the same locality, they lie at different strati- 
graphic horizons, either within the same formation or in 
different formations, although in practically all cases both 
lie on resistant rock. (4) If the Lancaster plain be project- 
ed from districts where the Dodgeville plain is missing into 
areas where the Dodgeville plain occurs it is found to lie 
distinctly below the Dodgeville plain. Similarly the Dodge- 

1. Grant, U. S. and Burchard, E. F., Lancaster-Mineral Point Folio, U. S. Geol. 
Surv., p. 2. 

2. Hughes, U. B., Proc. la. Acad. Sci., Vol. 23, p. 131. 



EROSION AL HISTORY OF DRIFTLESS AREA 93 

ville plain projected from cuesta to cuesta, lies on the 
average 200 feet higher than the Lancaster plain in the 
inter-cuesta areas. (See Figs. 14 and 23), (5) Where 
both plains are found together the change from one to the 
other takes place either along lines parallel with or oblique 
to the strike. (6) There are many places along the main 
south-flowing streams, for instance, along the Mississippi 



Fig. 24. A profile from Mt. Ida on the Dodgeville Prairie south across a portion of 
the Lancaster plain. The profile makes it clear that two plains are represented. 
(After U. B. Hughes). 

river, where upland surfaces representing the Lancaster 
plain can be traced continuously from an inter-cuesta area 
across a cuesta, on the summits of which the Dodgeville 
plain is represented, to connect definitely with the Lancas- 
ter plain in another inter-cuesta area (Fig. 25). There are 
lines along which the Lancaster plain is unbroken by rem- 
nants of the Dodgeville plain for the whole north-south ex- 
tent of the Driftless Area. (7) If it be assumed that the 
Lancaster plain in an area south of a Dodgeville cuesta is 
merely the projection of the Dodgeville plain down the dip 
of the strata, so that the two plains together form the 
gentle southerly slopes of normal cuestas (Fig. 16), three 
points located so as to include both plains, should show a 
surficial slope parallel with stratigraphic dips. That this 
assumption is not true is shown by the table on page 95, 
in which both plains are represented in each computation. 
Nowhere do the slopes of the surface and the dips of the 
strata coincide. 



94 IOWA STUDIES IN NATURAL HISTORY 



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Obviously the Lancaster plain 
is not an original marine plain of 
deposition, neither was it formed 
by marine denudation. Lying as 
it does here at one stratigraphic 
horizon and there at another, it 
cannot be a simple structural 
plain. Because the Lancaster 
plain is represented by many 
broad, flattish, intermediate sur- 
faces close enough together to 
warrant correlation ; because it is 
distinct from the Dodgaville 
plain; because it has a general 
southerly slope; because its slope 
is not parallel with the under- 
lying strata; because the plain 
bevels the edges of the strata ; be- 
cause its surface has about the 
degree of irregularity and slope 
which a peneplain should have; 
because it is not confined to cuesta 
belts but has a wide distribution 
in the inter-cuesta areas the Lan- 
caster plain seems even more 
surely to be a true peneplain than 
is the Dodgeville plain. It cannot 
be held to be a series of unrelated 
cuestas. The Lancaster plain, 
therefore, is believed to be a true 
peneplain, younger than the 
Dodgeville plain, uplifted since 
its formation, and now approach- 
ing thoro?igh dissection in the 
present cycle of erosion. For an 
additional illustration of the feat- 
ures on which this belief is based, 
see Fig. 26. It should not be 
understood that this surface was 



EROSION AL HISTORY OF DRIFTLESS AREA 95 



COMPUTATIONS SHOWING THE RELATION BETWEEN THE SLOPE OF A PLAIN 

MADE BY THE COMBINATION OF THE DODGEVILLE AND LANCASTER 

PLAINS AND THE DIP OF THE STRATA 



o g 



General Location 



Location of Points 



.So 1 



3* 

-p ft 

O «H 



Lancaster 
Quadrangle 



Denzer- 
Sparta-Rich- 
land Center 
Quadrangles 



A-Fennimore (Dcdge- 
ville plain) 

B-Blake Prairie 
(Lancaster plain) 

C-Rockville (Lan- 
caster plain) 

A-Denzer (Dodge- 
ville plain) 

B-Sparta (Do(Jge- 
ville plain) 

C-Loreta (Lan- 
caster plain) 



S16°W 15. S27°W 22.8 



S41°W 40: S28°W 14. 



Waukon A-Church (Dodge- 

Quadrangle ville plain) 

in Iowa B-3% mi.S. E. of Lan- S 76 ( 

sing ( Lancaster plain ) 
C-3 mi. S. E. of Wat- 
son ( Lancaster plain ) 



E 20.6 S27°W 20. 



Iowa- A-Near Graham, Iowa 

Wisconsin- (Dodgeville plain) 

Illinois B-Lancaster, Wisconsin 

(Lancaster plain) N 78 ( 
C-Stockton, Illinois 

(Lancaster plain) 



E 



5.2 S 6°W 8. 



flat before its uplift and dissection. Many remnants of the 
higher surfaces stood above it, and even its general lowland 
topography lacked much of being perfectly flat, as is true 
of all peneplains. 

The Lancaster plain even considered alone, bears strong 
evidence in favor of the plural cycle theory. And there is 
corroborative evidence of other sorts which adds still fur- 
ther to the strength of the case thus far developed. 

Antecedent Streams 
The antecedency of streams and the nature and value of 
the evidence it bears on the erosional history of a region 
were discussed in Part I, pp. 21-24. Streams may become 
antecedent (1) by local warping of the strata and surface 
of a region after the course of the streams have been estab- 



96 



IOWA 



STUDIES IN NATURAL HISTORY 







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lished, if the diastro- 
phic warping takes 
place so slowly that 
the streams can de- 
grade the up-warped 
areas as fast as they 
are uplifted, and thus 
hold their courses as 
conditions change, or 
(2) by the unnorm 
uplift of a surface 
which has been re- 
duced to grade and on 
which the streams 
have reached a final 
stage of adjustment, 
flowing by the most 
direct routes to the 
sea, provided again 
the streams hold their 
courses during and 
after uplift. 

By study of the 
Driftless Area it be- 
comes reasonably cer- 
tain that the tilting 
and slight warping 
which the strata have 
undergone antedated 
the establishment of 
the courses of the 
present streams, for 
all the structures are 
bevelled by the Dodge- 
ville and Lancaster 
plains. Either the 
streams of the Drift- 
less Area are in har- 
mony with conditions 



EROSION AL HISTORY OF DRIFTLESS AREA 97 

of slope, resistance, and structure and with the stage of early 
maturity, or they are antecedent and have courses now 
which they acquired in some late stage of a previous cycle. 
If the streams are merely consequent it would seem that the 
surface of the Drif tless Area is in its first erosional cycle. 
If they are antecedent they furnish valuable evidences of 
more than one cycle in the erosional history of the region. 
In case there has been but one cycle of erosion all the 
streams should be consequent; if there has been more than 
one cycle the larger streams are likely to be antecedent, 
having developed their courses in the first cycle and held 
them into the second, and the many tributary streams 
should have been developed in the present cycle and be con- 
sequent. The problem then involves especially the major 
streams. 

Mississippi River 

Study of the present course of the Mississippi river shows 
certain anomolies in its relations to original topography and 
structure, which are significant. These anomolies can be 
made most clear by a study of the various stages of adjust- 
ment which major streams should have in the normal ero- 
sional cycle under conditions existing in the Drif tless Area, 
and by comparison of the course of the Mississippi river 
with these various stages, considering the present mature 
condition of the region. 

As has been stated in previous pages, the strata south 
from La Crosse and Sparta dip in an average direction 
S 26°W to an average amount of 14.6 feet to the mile. But 
north of Winona along the Mississippi a dip in the opposite 
direction is recorded by conformable stratigraphic contacts 
which decline appreciably from Winona to Minneapolis. 
The average dip of the strata north of the arch, which 
seems to run through Galesburgh, Winona, and St. Charles, 
determined by taking the averages of four computations by 
means of the three point method is found to be N 35° 
W 9.3 feet per mile. The highest portion of the 
original surface, therefore, must have been near Winona 
and the surface must have sloped down to the north and 



98 



IOWA STUDIES IN NATURAL HISTORY 



to the south from the divide. In the knowledge that the 
formation of this arch antedated the establishment of the 
present course of the Mississippi river and that the various 
rock formations do not thin out appreciably in approach- 
ing the crest of the arch, it is possible to reconstruct the 
original surface for a line following the present course of 
the Mississippi river. This surface is found to lie at 960 
feet at Bellevue, 1030 feet at Dubuque, 1520 feet at Prairie 
du Chien, 1850 feet at Lansing, 2000 feet at La Crosse, 1870 
feet at Winona, and 1410 feet at Minneapolis. A section 
showing this original surface and the attitude of the strata 
beneath it for the whole length of the Mississippi river 
from Minneapolis to Bellevue is shown in Fig. 27. 




Fig. 27. A section showing the original surface of the Driftless Area and the struc- 
ture of the strata along a line now followed by the Mississippi river. The total 
horizontal distance is approximately 250 miles. Vertical scale: 1 inch equals 360 feet. 



Such a surface would be eroded by streams which would 
exhibit different stages of adjustment in different stages 
of the erosion cycle. 

In the first stage of adjustment streams would form, 
flowing south and north from the crest of the arch. From 
the main streams, tributaries would develop which would 
curve headward up the slope of the plain toward the divide 
from either side. As all the streams in this first stage were 
flowing on the Niagara dolomite there were only slight 
differences in resistance, and the courses of the streams 
would be determined primarily by the topographic slopes 
which were in turn determined by the structure. The gen- 



EROSION AL HISTORY OF DRIFTLESS AREA 99 

eral northerly and southerly slopes from the axis of the 
arch were not steep, but are believed to have been steep 
enough to control the general courses of the streams. The 
details of the courses might be influenced by the minor 
structures such as anticlines, synclines, accentuations of 
the monocline, faults, joints, etc., by local irregularities in 
the surface, or by slight differences in resistance. The con- 
ditions during this first stage of adjustment are illustrated 
in Fig. 28. 




Fig. 28. Block diagram illustrating the drainage conditions in the Driftless Area, 
as they should have been in the initial stage of stream adjustment. 

As the main streams on the two limbs of the arch cut 
downward they would, somewhere in their courses, pene- 
trate the resistant Niagara dolomite and reach the relative- 
ly non-resistant Maquoketa shale. On this soft formation 
the main streams would develop broad valleys and would 
send out tributaries (Fig. 29). 

When maturity of the erosion cycle was reached and the 
inter-valley divides had been made narrow, the south-flow- 
ing main stream, having greater volume, or a higher gradi- 
ent, or flowing on less resistant material than the stream 
on the opposite side of the arch, might work headward 
through the main divide and steal water by reversion of 
the main stream flowing in the opposite direction. (Fig. 
30). In this case it seems that the pirate stream would 
work headward down the course already established by the 



100 IOWA STUDIES IN NATURAL HISTORY 

reversed stream, that is, in a line roughly parallel with the 

dip of the strata and with the original slope of the surface. 

Finally when old age has been reached and the main 




Fig. 29. Block diagram showing the drainage conditions in Stage II of stream ad- 
justment. 




Fig. 30. Block diagram illustrating Stage III of stream adjustment, in case the 
south-flowing stream has the advantage of the north-flowing one. 

streams have been reduced to grade throughout their 
courses, and not before that stream which has the shortest 
route to the sea would capture all the drainage and would 
adopt a course, which for the first time would be indepen- 
dent of structure and original slope and dependent upon 
the slopes of the graded plain. Some of the tributary 
streams, of which there would be few, might still be depen- 
dent upon structure (Fig. 31). 



EROSION AL HISTORY OF DRIFTLESS AREA 101 




Fig. 31. Blcck diagram showing the courses of the streams in a final stage of 
stream adjt,strrent in a first cyc.e of erosion. 

Now the present course of the Mississippi river in early 
maturity of the present cycle of valley development is al- 
most exactly what would be expected if it were determined 
by two streams flowing in opposite directions from the 
crest of the arch, the south-flowing stream having captured 
the north-flowing one, as outlined above (Fig. 32). North 




Fig 32. Block diagram showing roughly the course of the Mississippi river in its 

h«™ n rW 'W^a' T h V iver . 1S antec f dent in the sa ™ sense thS the Susque! 
hanna river m the Appalachians is antecedent. q 



of the axis of the arch, between Minneapolis and La Crosse, 
the river flows in the general direction, S 51°E, which is an 
angle of 164° with the average direction of dip of the strata. 
The river not only does not flow in the direction of the dip 
but it does not flow parallel with the strike. Its average 
direction lacks but 16° of being opposite to the dip and to 



102 IOWA STUDIES IN NATURAL HISTORY 

the slope of the original surface. The original surface had 
the theoretical altitude of 1410 feet at Minneapolis, 1870 
feet at Winona and 2000 feet at La Crosse, and the present 
river flows from Minneapolis, past Winona, to La Crosse. 
South of the axis of the arch and the main divide on the 
original surface, where the strata have an average dip in 
the direction S 26°W, which also must have been the aver- 
age direction of slope of the original surface, the river 
follows a curved course from La Crosse to Bellevue in the 
general direction S 18°E, forming an angle of 44° with the 
dip of the strata and the slope of the original surface. On 
neither side of the arch is there any evidence that the minor 
curves of the river really are controlled by minor structural 
features such as anticlines and synclines. 

It should also be borne in mind that the Mississippi river, 
by taking a course more nearly directly south at some point 
south of St. Paul, would have flowed around the southwest 
end of the plunging anticline, avoiding the crest of the 
arch and the high portion of the original surface entirely. 
Such a course also would have been little if any longer to 
Dubuque than the course which was actually established. 

There is a further indication that the Mississippi river 
has had such a history as outlined above in the fact that 
certain of the larger streams north of the axis of the anti- 
cline, for instance, Whitewater river, join the master 
stream with an acute angle down-stream. This suggests 
that the Mississippi river was flowing in the opposite 
direction while Whitewater river was being developed, and 
that its direction of flow was later reversed. 

This lack of harmony between rock structures and 
original slopes on the one hand and the present course of 
the Mississippi river on the other, cannot be explained on 
the basis of the ordinary superimposition. Such an inter- 
pretation could be correct only in case some post-Paleozoic 
formation on which the stream could have established its 
present course, had been deposited over the strata of the dis- 
trict, after they were deformed, so as to let the stream 
down on the stratigraphic structures and topographies as 



EROSION AL HISTORY OF DRIFTLESS AREA 103 

the covering formation was penetrated. No such covering 
formation is known to have existed in the Driftless Area; 
and it seems extremely unlikely that a deposit so thick did 
exist and has been so thoroughly removed that no remnants 
of it are left. There are a few patches of stream gravel 
on the uplands, which some have considered to be Creta- 
ceous and others Tertiary in age, but these deposits are 
local in their distribution and are believed by no one to 
have covered the entire Driftless Area. Certainly they did 
not cover it to such depths as to mask the present struc- 
tures. Neither is the glacial drift competent to cause such 
superposition, for there are considerable areas on both sides 
of the Mississippi which are driftless. Furthermore, the 
drift must have had a thickness of more than 600 feet at 
Minneapolis to have carried the river over the crest of the 
arch at La Crosse. 

Because the Mississippi river is generally independent of 
structure, because it flows for 135 miles in a direction which 
is up the slope of the original surface, because it cuts across 
the axis of a fold whose dips are considerable, because the 
surface of the Driftless Area is in maturity and shows no 
signs of old age, and because the river has not been super- 
imposed, the Mississippi river is believed to be antecedent 
and to record more than one cycle in the erosional history 
of the surface. 

The relations between the course of the Mississippi river 
and the Dodgeville and Lancaster plains north of La Crosse 
are not definitely ascertainable. On the south limb of the 
anticline, however, the general course of the river comes 
within 5° of being parallel in direction with the Dodgeville 
plain and within 6° of parallelism with the Lancaster plain. 
It seems likely therefore, that the river established its pres- 
ent course in old age of the cycle of erosion in which the 
Dodgeville peneplain was formed and held that course 
without great change during the dissection of the Dodge- 
ville plain and the formation of the Lancaster plain and 
while the Lancaster plain was being uplifted and eroded. 



104 IOWA STUDIES IN NATURAL HISTORY 

It is not known that this holds in detail for that part of the 
river north of La Crosse. 

Other Streams 

All the smaller tributary streams of the Driftless Area 
appear to have been formed in the present cycle of erosion, 
be it the first, second or third cycle which the Area has ex- 
perienced. It would seem likely, however, that if the 
Mississippi river existed in a previous cycle, some of its 
larger tributaries, such as the Wisconsin, La Crosse, Upper 
Iowa, Turkey, Root and Whitewater rivers might have 
established their courses at the same time and have held 
their courses to the present. 

Within the Driftless Area, Wisconsin river flows from 
Prairue du Sac to the Mississippi in a general direction 
S 73°W, which is at an angle of 47° with the general dip of 
the strata and what must have been the slope of the original* 
surface. The whole course of the river in this distance is 
on Potsdam sandstone, but before it had cut quite so deeply 
it must have flowed from the soft sandstone, across the re- 
sistant Prairie du Chien dolomite, instead of remaining on 
the soft sandstone as it could have done by developing a 
course more nearly parallel with the strike of the strata. 
As Wisconsin river is not adjusted to the structure the con- 
clusion seems reasonable that it probably developed a course 
in harmony with conditions which existed in old age of a 
previous cycle and held that course during rejuvenation. 
In the sense in which Willis, Davis, and Hayes and Camp- 
bell used the term in connection with certain rivers of the 
Appalachians, Wisconsin river is, then, probably antecedent 
and an evidence of more than one cycle of erosion. 

The direction of dip of the strata in the neighborhood of 
La Crosse river near the crest of the arch is not known 
accurately, and it is not known whether the river, which 
flows S 56°W is parallel with or oblique to the axis of the 
anticline. It may, therefore, be antecedent or consequent. 

The courses of the streams in Iowa doubtless have been 
influenced by glacial drift which extends eastward almost 
or quite to their points of junction with the Mississippi; 



EROSION AL HISTORY OF DRIFTLESS AREA 105 

and the problem of their antecedency is therefore obscured. 
Upper Iowa river has a course N 46°E from Decorah to its 
mouth, which fails of parallelism with the dip by 142°. In- 
deed the river flows for 35 miles in a direction which must 
have been up an original slope of 10 or 15 feet per mile. If 
glaciation had nothing to do with the establishment of this 
course Upper Iowa river is probably antecedent. Turkey 
river below Elkader flows in the general direction S 66°E. 
As this makes an angle of only 2° with the strike of the 
strata, Turkey river may be considered to be adjusted in 
harmony with its development within a single cycle. In 
Minnesota, Root river has a course out of harmony with 
the structure and the slopes of the theoretic original sur- 
face. It flows in a general direction which is up a strati- 
graphic dip of 4 feet per mile, although by taking a more 
southerly course it could have flowed around the end of 
the plunging anticline. Although Whitewater river north 
of the axis of the arch, as stated on p. 102, flows in a 
direction which is in harmony with structure and original 
slope, it joins the Mississippi with an acute angle down- 
stream, suggesting the possibility that its course was estab- 
lished according to original slope and maintained after re- 
versal of the master stream. Thus, while there is little 
suggestion of antecedency for the Whitewater river itself, 
its course taken in connection with the course of its main, 
adds strength to the belief that the establishment of the 
present course of the upper Mississippi involved a case of 
piracy of a magnitude which could hardly have taken place 
all within the present cycle of erosion. 

In Illinois, Sinsinawa Creek, Galena River, Smallpox 
Creek, Apple River and Plum River are so nearly parallel 
with the dip that their histories probably do not date back 
of the present erosional cycle. 

Intrenched Meanders 

If the erosional history of the Driftless Area has involved 

more than one cycle of erosion it seems that some of the 

streams at least should have developed meanders in old age 

of a cycle and intrenched their meanders in the later cycle 



106 IOWA STUDIES IN NATURAL HISTORY 

following uplift. The difficulty in distinguishing intrenched 
meanders from curves made in other ways not involving 
more than one cycle of erosion is brought out in Part I, 
as are also other limitations and possibilities in the applica- 
tion of intrenched meanders to interpretations of the ero- 
sional histories of regions. 

The two major streams of the Driftless Area, the Mis- 
sissippi and Wisconsin rivers, show no intrenched mean- 
ders, in spite of the fact that they seem to have had a 
history which would have developed such features. Both 
streams have flood plains several times the widths of the 
rivers and the details of their present courses are what 
would be expected under these conditions ; but their curves 
are not intrenched. Except for their details, the general 
courses of these rivers are quite remarkably straight. If 
the streams were at grade on the Dodgeville plain and de- 
veloped meanders there they must have straightened their 
courses as they cut down toward the Lancaster plain. 
Either the Lancaster peneplain was not sufficiently flat- 
tened for the development of conspicuous meanders or 
meanders were formed in this second cycle and cut off again 
after uplift of the Lancaster plain. It is not unreasonable 
to suppose that such streams would straighten themselves 
after rejuvenation; indeed, it is not clear that a stream 
could maintain the meanders developed in one cycle much 
past maturity of the following cycle. Therefore, the absence 
of intrenched meanders in these major streams is not 
thought to argue strongly against the idea that the Drift- 
less Area has suffered more than one cycle of erosion. On 
the other hand the curves of these streams have nothing to 
offer in favor of this idea. 

Conditions are somewhat different in the cases of smaller 
streams. Upper Iowa, Yellow, Turkey, and little Maquoketa 
rivers in Iowa are quite crooked and spurs from the valley 
walls project into the curves. But a large part of the 
courses of these streams lie in an area which has been 
glaciated, and the curves may have been developed on the 
surface of the drift and superimposed on the bedrock. But 



EROSIONAL HISTORY OF DRIFTLESS AREA 107 

on the east side of the Mississippi river in Wisconsin and 
Illinois, where the area has never been glaciated and where 
there is no other known cause for exceptionally crooked 
-streams, Trempeleau, Black, Kickapoo, Grant, Platte, Little 
Platte, Pecatonica, Galena, and Apple rivers all have dis- 
tinctly crooked courses where the area has never been 
glaciated and where there is no other known cause for ex- 
ceptionally crooked streams (Fig. 33). Kummel 1 studied 




Fig. 33. A map showing a portion 
of the course of Galena river near 
Benton, Wisconsin. The curves may 
constitute intrenched meanders. 
(After Martin). 



the Galena, Platte, Grant, and Pecatonica rivers, described 
their meandering courses and their mature valleys, and 
concluded that they could not have been developed in a 
single cycle, either by superposition or by inequalities in 
resistance of rock. He concluded that they are true in- 
trenched meanders significant of more than one cycle of 
erosion. His argument is convincing but hardly conclusive. 
There are so many ways in which curves might be developed 
and so difficult is it to distinguish curves made in differ- 

Vol K ^™895) H ' B "714 S ?16 e meandering rivers of Wisconsin," Science, New Series, 



108 IOWA STUDIES IN NATURAL HISTORY 

ent ways, that the writer believes that these intrenched 
curving streams, considered alone without reference to re- 
lations between mains and tributaries, might have acquired 
these curves without having experienced more than one 
cycle. On the other hand it is believed that these intrenched 
curves bear as much evidence in favor of the plural cycle 
theory as intrenched meanders ever afford. 

Associated Sets of Crooked and Straight Streams 

But if the crooked courses of these streams within the 
Driftless Area have been developed in a single cycle their 
tributaries must have had the same histories as the mains 
and should have courses as crooked as the courses of the 
mains. Neither in the case of the above-mentioned streams 
in the Driftless Area of Wisconsin and Illinois nor of those 
in the slightly glaciated portion of Iowa do the mains and 
the tributaries have comparable natures and degrees of 
crookedness. 

The fact that the tributaries are less crooked than their 
mains in Iowa is not significant, for it is possible that the 
main streams developed their course in the drift and that 
the tributaries were developed under different conditions 
after superimposition had been accomplished. 

In the cases of those streams in areas which were not even 
slightly glaciated, however, and in which the tributaries 
are straight and the mains are notably curved, a suggestion 
is offered that the histories of the main streams and of the 
tributaries have not all been worked out in a single cycle. 
It would seem likely that the mains developed meanders 
when they were at grade in maturity or old age of a previ- 
ous cycle of valley development and that either the tributar- 
ies had not reached grade and therebore did not meander be- 
fore the first cycle was interrupted, or the tributaries did 
not exist at the close of the first cycle and have developed 
their straight courses entirely under conditions of higher 
gradient in the present cycle. 

There is a marked difference in degree of crookedness be- 
tween tributaries and mains in practically all of the drain- 
age systems intermediate in size between the largest and 



EROSIONAL HISTORY OF DRIFTLESS AREA 109 

the smallest, as illustrated in Fig. 34. This fact is of some 
value as evidence in favor of the idea that more than one 
cycle was involved in the erosional history of the Driftless 




Fig. 34. A plat of part of the course of Grant river and its trib- 
utaries. The fact that the tributaries are not nearly so crooked as 
the main stream suggests that the curves of the river were developed 
in the last stages of a previous cycle and that the tributaries were 
mainly or wholly developed in the present cycle. 

Area. This evidence is chiefly corroborative, however, and 
is not conclusive considered alone. 

Stream Terraces 

The Driftless Area abounds in stream terraces of vari- 
ous sorts, but none of them is significant as an evidence of 
more than one cycle of erosion. 

At many points throughout the area there are projections 
or benches along the valley walls, whose tops are more or 
less flat,. whose outer faces are steep, and to which the term 
terraces might be applied. These features are well known 



110 IOWA STUDIES IN NATURAL HISTORY 

in Jo Daviess County, Illinois 1 , in the Sparta district 2 and 
along the Wisconsin river 3 in Wisconsin, and in many of 
the valleys of Iowa, notably in the valley of Village Creek. 
These terraces are formed by resistant layers of rock at 
various stratigraphic horizons, as for instance, certain re- 
sistant sandstone layers in the Potsdam formation, the 
Mendota limestone member, the cherty member of the Ga- 
lena formation, and the calcareous beds in the upper Ma- 
quoketa. They are purely structural, occur at different 
levels, cannot be correlated with either the Dodgeville or 
the Lancaster plain, and cannot be used as evidence of more 
than one cycle of erosion in the Driftless Area. 

In several of the main tributaries of the Wisconsin river, 
notably in the valley of the Kickapoo river and the valley 
of Pine creek, there are distinct and almost continuous ter- 
races which slope gently downstream. They consist of non- 
resistant rock, and bevel the layers of the Potsdam sand- 
stone. The valleys have a double appearance, there being 
a narrow, rock-bound valley within a much wider, older 
one. These terraces are also due indirectly to structure. 
The Wisconsin river flows west and south with a gradient 
considerably less than the slope of the strata in that direc- 
tion, so that its bed is on progressively younger strata to- 
wards its mouth. Although it has now penetrated the re- 
sistant Prairie du Chien formation where it joins the Mis- 
sissippi, there was a time when its lower course was in this 
resistant formation and its upper course and its tributaries 
were on the Cambrian sandstone. Under these conditions 
the degradation was so much slower on the Prairie du Chien 
formation than was possible upstream on the sandstone that 
a temporary grade was established and maintained on the 
sandstone. There the main and tributary streams developed 
broad, open valleys with flat bottoms. When the resistant 
dolomite at the mouth of the river was finally cut through 
the sandstone beneath it was excavated rapidly and the 
streams above the resistant rock were allowed to intrench 



1. Trowbridge. A. C. and Shaw, E. W., Bull. No. 26, III. Geol. Surv., pp. 144-5. 

2. Martin, Lawrence, Bull. Geol. Soc. Am., Vol. 28, pp. 148-149. 

3. MacClintock, Paul, The Wisconsin River between Prairie du Sac and Prairie du 
Chien, manuscript so far unpublished. 



EROSIONAL HISTORY OF DRIFTLESS AREA 111 

themselves. The renewed activity was felt last in the tribu- 
tary valleys and the terraces have therefore been eroded 
least there, so that they are now most conspicuous in val- 
leys tributary to the main streams rather than in the main 
valley itself. There are coarse stream-laid gravels on some 
of these terraces, as for instance in the valley of Pine Creek 
southwest of Richland Center, and in the valley of Honey 
Creek near Plain. It is clear that these terraces also are 
not significant in connection with the erosional history of 
the general surface of the Driftless Area. 

Flat-topped terraces, consisting of alluvial and lacustrine 
materials are found abundantly in nearly all the larger 
tributary valleys to the Mississippi and Wisconsin rivers. 
The origin of these terraces has been worked out 1 and found 
to be due to a partial filling of the Mississippi and Wiscon- 
sin river valleys by fluvio-glacial material at the time of 
the Wisconsin ice invasion, the consequent ponding of the 
tributaries, and the re-excavation of the fill in the mains 
and the tributaries after the retreat of the Wisconsin 
glacier. The origin of these terraces too has little to do 
with the general erosional history of the Driftless Area as 
a whole. 

Although there are many terraces in the Driftless Area, 
it is concluded that none of them bears evidence of more 
than one cycle of erosion in the region. 

Upland Fluvial Deposits (high level gravels) 
One of the best evidences that there have been more than 
one cycle of erosion in the Driftless Area is found in the 
fact that stream deposits exist on some of the summit sur- 
faces of the Area. These deposits have been known for a 
long time and have usually been referred to as "high-level 
gravels." 2 As the term implies, these deposits occupy the 
highest portion of the topography and consist almost en- 
tirely of gravel. 



1. Trowbridge, A. C. and Shaw, E. W., Bull. No. 26, III. Geol. Surv., pp. 145-152. 

2. Strong, Moses, Geol. Wis., Vol. IV, 1875-79, p. 88. 

Winchell, N. H., Geol. and Nat'l Hist. Surv. Minn.. Vol. I, 1884, pp. 305-310 ; 353-356. 
Chamberlin. T. C. and Salisbury, R. D., Sixth Ann. Eept. U. S. Geol. Surv., 1884- 
85 p. 273. 

Salisbury, R. D., Bull. Geol. Soc. Am., Vol. 3, 1892, pp. 183-186 ; Jour. Geol., Vol. Ill, 
1895, pp. 655-667. 



112 IOWA STUDIES IN NATURAL HISTORY 

So far they have been found at Seneca, Wisconsin, on the 
flat summit of the south quartzite range near Devil's Lake, 
Wisconsin, on the summit plain in the south portion of the 
Sparta quadrangle north of Cashton in Wisconsin, in the 
Tomah quadrangle, Wisconsin, at Iron Hill near Waukon, 
near Church, and near Elon in Iowa, and in various portions 
of the Driftless Area in Minnesota. In all these places the 
gravel is thick enough to form a measurable deposit and at 
Senaca and Waukon the thickness is as great as 35 feet. The 
deposit occupies summit positions in the topography, which 
position represents the Dodgeville plain in each case. In 
addition to these localities where the gravel is in place, there 
are many places in Iowa and Illinois and probably in Wis- 
consin and Minnesota, where scattered pebbles which have 
been derived from the deposit are found at all levels. How- 
ever, there is no place known where the gravel lies in its 
original position at levels below the Dodgeville plain. At 
Devil's Lake they are associated with potholes in the sum- 
mit surface. It is not believed that these patches of gravel 
are remnants of a formation which once covered the entire 
Driftless Area, but that the gravels were deposited only 
along stream courses. 

There can be no doubt that these gravels are of fluvial 
origin. The pebbles range in size from a small fraction of 
one inch to three or four inches in diameter. The smaller 
ones are rounded and highly polished and seem to have been 
carried far, or at least to have undergone transportation 
for a long time. The large ones are more irregular and 
some of them seem hardly to have been transported at all. 
At Seneca, Waukon and Elon, the gravel deposits are dis- 
tributed in crescent shaped areas resembling the curves of 
streams. 

The writer has broken hundreds of the pebbles and has 
yet to And one composed of anything but silica. Most of 
them are chert, but some are white quartz, some are almost 
black, and some have the color and appearance of jasper 
and chalcedony. They are known to include nothing which 
could not have been derived from the pre-Cambrian and 
Paleozoic formations which originally covered the Driftless 



EROSIONAL HISTORY OF DRIFTLESS AREA 113 

Area. At Waukon, Elon, Seneca, and at some points in 
Minnesota, the gravel is firmly cemented with iron, so that 
a conglomerate exceedingly resistant to erosion is formed. 

Some of the pebbles contain fossils which are of Ordo- 
vician and Niagaran age. Some of the pebbles and fossils 
collected from the Sparta quadrangle are shown in Fig. 35. 

The conclusion seems unavoidable that streams were once 
nearly at grade on the Dodgeville plain; that they deposited 
extensively in their beds, and that deposition ceased as the 
dissection of the summit plain was inaugurated by uplift. 
The coarse texture of the fluvial deposit, their apparently 
local origin, and their association at Devil's Lake with 
potholes all suggest that they were not deposited by the 
largest and oldest streams of the time, but rather by second- 
ary streams whose gradients were still appreciable and 
whose sources were not far distant, and yet by streams 
which have long since ceased to exist. Presumably the 
larger streams deposited also, but the material probably 
consisted of sand and silt rather than of gravel, and these 
non-resistant deposits have been entirely removed or 
mingled with the upland soils so thoroughly as to be indis- 
tinguishable. The gravel was probably deposited on those 
portions of the Dodgeville plain which were somewhat 
above the lower valley bottoms, and by subsequent erosion 
they have come to stand as the very highest points because 
of their superior resistance. 

Whatever may have been their detailed origin and dis- 
tribution these fluvial gravels, occurring at widely separated 
points on the Dodgeville plain, hundreds of feet above pres- 
ent drainage, go far to prove that the surface of the Drift- 
less Area has not been formed by erosion in a single cycle. 
Certainly there is no provision in the cuesta single cycle 
theory for the occurrence of these deposits on the Dodge- 
ville plain. 

Conclusion 

As was brought out in Part I, the most satisfactory proof 
of more than one cycle of erosion is to be found in certain 
combinations of evidences. A combination amounting to 



114 IOWA STUDIES IN NATURAL HISTORY 




Fig. 35. Pebbles and fossils from the summit fluvial deposits in the south portion of 
the Sparta Quadrangle. (After Shipton) . 



EROSION AL HISTORY OF DRIFTLESS AREA 115 

proof exists in the Driftless Area. It is impossible that a 
surface could have been developed in a single cycle of ero- 
sion, which has (1), even-crested summit areas which, after 
analysis, represent a peneplain, (2) an intermediate plain 
which can be interpreted only as a partial peneplain, (3) 
antecedent streams which could have developed their pres- 
ent courses only in old age of an erosion cycle, (4) in- 
trenched meanders for which no other explanation than that 
they record more than one cycle have been worked out, (5) 
associated sets of crooked and straight streams which are 
valuable corroborative evidence of plural cycles, and (6) 
undoubted fluvial deposits widely distributed on flat sur- 
faces far above present drainage. 

THE NUMBER OF EROSIONAL CYCLES 

The next question which confronts the interpreter of the 
erosional history of the Driftless Area has to do with the 
number of cycles of erosion which have been involved in 
the formation of the surface. The question can be answered 
when it has been determined how many distinct sets of 
evidences of more than one cycle are included among the 
five evidences outlined above. 

In the first place, there is no way to ascertain how many 
cycles, if any, intervened between the time of withdrawal 
of the last Paleozoic sea and the cycle in which the Dodge- 
ville plain was formed. There may have been time for 
several cycles of erosion between these dates. But of any 
such cycles all evidence was obliterated in the making of 
the Dodgeville plain. If it be assumed that the cycle which 
was inaugurated by the final withdrawal of the sea was 
the same cycle as that in old age of which the Dodgeville 
plain resulted, there would be no way to prove the assump- 
tion to be incorrect. 

Considering the evidences of more than one cycle of ero- 
sion it is clear that the Dodgeville plain and the Lancaster 
plain could not have been formed in the same cycle. From 
foregoing discussions it is clear that the antecedent streams 
and upland fluvial deposits go with the Dodgeville plain, 
and the intrenched meanders and associated sets of crooked 



116 IOWA STUDIES IN NATURAL HISTORY 

and straight streams with the Lancaster plain. Even- 
crested summit areas, antecedent streams and fluvial de- 
posits on divides constitute evidence of one ancient cycle, 
and an intermediate plain which is a partial peneplain, in- 
trenched meanders and associated sets of crooked and 
straight streams afford evidence of another one. Below 
the intermediate plain the streams in their deeply excavated 
valleys show that a third cycle is involved. 

It is believed that the surface of the Driftless Area has 
been eroded in at least three cycles, the first known one 
being represented to-day by the Dodgeville plain, the second 
one by the Lancaster plain, and the third one by the pres- 
ent valleys below the Lancaster plain. These- cycles are 
called the Dodgeville cycle, the Lancaster cycle and the 
present cycle respectively. 

THE HISTORY OF DIASTROPHISM 
The first recorded diastrophic event involved in the ero- 
sional history of the Driftless Area caused the warping of 
the strata to form the anticline with its axis crossing the 
Mississippi river at or near La Crosse, and with its south 
and north dipping limbs, together with the gentle and local 
anticlines and synclines on the limbs of the larger fold. 
This movement may or may not have accompanied or 
caused the final withdrawal of the Paleozoic seas. It was 
an uplift of the surface with warping. 

After the initial movement and the establishment of the 
land surface, after the streams had reached grade and de- 
veloped the Dodgeville plain, an uplift occurred which in- 
terrupted the Dodgeville cycle and inaugurated the Lan- 
caster cycle. Although the Dodgeville plain is not perfect- 
ly parallel with the Lancaster plain nor with the present 
flood plain of the Mississippi river, this uplift was not ac- 
companied by marked warping or tilting. The local irregu- 
larities of the Dodgeville and Lancaster plains are clearly 
due to erosion rather than to diastrophism and are neglect- 
ed in the following estimates. The relative directions and 
amounts of slope of the Dodgeville plain, the Lancaster 



EROSIONAL HISTORY OF DRIFTLESS AREA 117 

plain, and the graded plain of the Mississippi river, south 
of La Crosse, are shown in the accompanying table. 

TABLE SHOWING THE RELATIVE DIRECTIONS AND AMOUNTS OF SLOPE OF 

THE DODGEVILLE PLAIN, THE LANCASTER PLAIN, AND 

THE MISSISSIPPI FLOOD PLAIN 



Plain 

Dodgeville Plain 
Lancaster Plain 
Mississippi Flood Plain 


Average direction of slope 

S23°E 
S40°E 
S18°E 


Average amount of slope 

3.3 feet per mile 

3 feet per mile 

4 inches per mile 



The difference in direction of slope of the Dodgeville and 
Lancaster surfaces is not great, considering the possibilities 
of error in estimating averages, and could be due to differ- 
ences in direction of drainage during the respective cycles. 
Consequently, they cannot be said to record warping or 
tilting of the Dodgeville surface during uplift. The amounts 
of slope of the Dodgeville and Lancaster plains are almost 
identical, which seems to prove that there was no notable 
tilting of the Dodgeville surface before the formation of 
the Lancaster plain. The second diastrophic movement 
recorded in the features of the surface was then one of 
nearly uniform uplift. 

The amount of this uplift can be ascertained at least 
roughly by the average difference in altitude between the 
Dodgeville plain and the Lancaster plain. On the average 
these two plains are 235 feet apart vertically in the Bara- 
boo district, 265 feet in the Sparta quadrangle, 148 feet in 
the Richland Center quadrangle, 175 feet in the Lancaster 
and Mineral Point quadrangles, 218 feet in Jo Daviess 
County, Illinois, 117 feet in the Waukon quadrangle, 190 
feet in the Elkader quadrangle, 125 feet in southeastern 
Minnesota. As the average of these figures is 184 feet, the 
second recorded diastrophic movement was an uplift of 
about that amount. 

The Lancaster cycle was interrupted by a third uplift 
which was the greatest of all the movements which affected 
the Driftless Area. Streams which had developed graded 
flats on the Lancaster plain during the Lancaster cycle were 
able in the following cycle to cut to the levels of the bottoms 
of the rock valleys below the later fluvio-glacial fills. The 



118 IOWA STUDIES IN NATURAL HISTORY 

average depth of the valleys cut during this cycle is ap- 
proximately the amount of the uplift which closed the Lan- 
caster cycle. The following table gives details of the depths 
of valleys cut during this cycle. 



TABLE SHOWING DEPTHS OF VALLEYS WHICH MEASURE THE AMOUNT OF 
THE UPLIFT WHICH INTERRUPTED THE LANCASTER CYCLE 





Altitude of 


Altitude of 


Depths of Valley 


Valley 


Lancaster 


rock bottom of 


below the Lancaster 




plain (feet) 


valley (feet) 


plain and amount 
of uplift (feet) 


La Crosse River 








near Sparta 


1100 


600 


500 


Devils Lake Gap 


1200 


570 


630 


Galena River near 








its mouth 


860 


490 


370 


Upper Iowa River 








near its mouth 


1150 


530 


620 


Mississippi River 








at La Crosse 


1100 


470 


630 


Mississippi River at 








Prairie du Chien 


1100 


473 


627 


Mississippi River 








at Dubuque 


880 


279 


601 



Considering the fact that not all the wells, the records of 
which were used for the altitudes of the bedrock beneath 
the surfaces of the fills, are in the middles of the valleys 
and the probability that not all the streams had reached 
grade when the filling began, the depths of these valleys 
are quite remarkably uniform. This average depth, ap- 
proximately 600 feet, seems to be a fair estimate of the 
amount of uplift. If the streams were not at grade when 
degradation ceased and aggradation began the amount of 
uplift may be considered to have been more than this. Of 
the two uplifts which have occurred since the land surface 
of the Driftless Area was established the second one was 
three times as great as the first. 

From the table showing the relations between the two 
upland plains and the bottoms of the present Mississippi 
Valley, (p. 117) , the inference might be drawn that the up- 
lift which interrupted the Lancaster cycle was accompanied 
by tilting, for the Lancaster plain and the present Missis- 
sippi flood plain are not parallel. However, the nature of 
this uplift is to be obtained by comparison of the Lancaster 



EROSIONAL HISTORY OF DRIFTLESS AREA 119 

plain not with the present flood plain, but with the rock 
bottom of the valley beneath the present river level. The 
streams rejuvenated by the uplift of the Lancaster plain 
continued to cut downward until the rock bottoms of the 
present valley were reached. The present flood plains of 
the streams were established later, under different condi- 
tions. Although it is impossible to determine the exact 
slope of the surface represented by the buried bock bottoms 
of the valleys, it is shown in the last table that the depths 
of the valleys cut during the post-Lancaster cycle and con- 
sequently the amount of uplift which inaugurated that 
cycle are notably uniform. This suggests that the pene- 
plain which would have been developed if this cycle had 
gone to a late stage would have been roughly parallel with 
the Lancaster plain. This being the case the uplift of the 
Lancaster plain is more likely to have been uniform than 
accompanied by tilting. 

The rather low altitudes of the parallel Dodgeville and 
Lancaster plains in Minnesota suggests the possibility that 
the movement which interrupted the Lancaster cycle was 
accompanied by warping in that state. On the other hand, 
a slightly decreased slope in old age of each of the two cycles 
or a slight change in the direction of slope of the two plains 
would explain the slight discrepancy equally well. 

There seems to be no escape from the conclusion that 
there has been still another period of diastrophism in the 
Driftless Area, this time a subsidence rather than an eleva- 
tion of the surface. The evidence of subsidence is found in 
the fact that the Mississippi river and its main tributaries 
are now at grade at levels on the average 180 feet above 
levels to which they were formerly able to reduce their 
beds. It is not believed that this fact is to be explained on 
the supposition that the present grade is merely temporary 
and controlled by some obstruction such as the rock ledge 
at Rock Island or the rapids at Keokuk. These obstructions 
are far from sufficient to explain the difference in grade 
levels now and as they were, for the Mississippi river to- 
day has a gradient of less than 6 inches per mile from La 
Crosse to the Gulf, including the rapids. It is believed, 



120 IOWA STUDIES IN NATURAL HISTORY 

therefore, that the last diastrophic movement in the history 
of the Driftless Area was a subsidence of about 150 to 200 
feet and that it took place sometime before, during, or just 
after the partial filling of the valleys by fluvio-glacial 
debris. 

If it be assumed that this subsidence was accompanied 
by tilting, so that the south portion of the Driftless Area 
subsided more than the north portion, the apparent parallel- 
ism of the Dodgeville plain, the Lancaster plain, and the 
rock-bottomed valleys, and the more gentle slope of the 
present Mississippi flood plain would be explained. This 
assumption is rendered unnecessary, however, if it be con- 
sidered that the present Mississippi has a sufficiently great- 
er volume and lighter load than all previously existing 
streams, to allow it to develop and maintain a gradient one- 
tenth as steep as any preceding gradient. 

The conclusion is reached, therefore, that at least four 
different diastrophic movements affected the Driftless Area, 
namely, (1) uplift with warping and tilting which initiated 
the land surface; (2) a nearly uniform uplift of about 180 
feet interrupting the Dodgeville cycle; (3) a nearly uni- 
form uplift of 600 feet or more which started the excavation 
of the deep valleys; and (4) a subsidence, perhaps accom- 
panied by tilting, which raised the level of grade to that of 
the present Mississippi river. 

THE DATES OF EVENTS 

The whole history presented in this paper is limited in 
time between the Niagaran epoch on the one side and the 
Wisconsin epoch on the other. The sequence of events has 
already been worked out. The accuracy with which the 
dates of these events can be stated depends upon the ac- 
curacy with which the ages of the upland plains can be de- 
termined. There has been disagreement concerning the 
ages of these plains and perhaps the final conclusion will 
have to await further work, but strong evidence now at 
hand leads to the conclusions here presented. 



EROSIONAL HISTORY OF DRIFTLESS AREA 121 

The Age of the Dodgeville Plain 
There is no known way to determine the age of the 
Dodgeville plain by a study confined to the Driftless Area. 
The most promising method lies in the attempt to determine 
the age of the high level gravels which are contemporane- 
ous with the plain. In 1882 Winchell 1 discovered silts and 
sands and clays of undoubted Chetaceous age in southeast- 
ern Minnesota, and in the same district he found a gravel 
deposit later found to be similar in some respects to the 
hige-level gravel of the Driftless Area. Because the gravels 
were associated with the Cretaceous deposits Winchell 
tentatively assigned a Cretaceous age to them. In 1895, 
after study of the Tertiary gravels of the Gulf Coast and 
of Arkansas and southern Illinois, and after seeing the 
gravel deposits of the Driftless Area at Seneca and Devil's 
Lake, Salisbury 2 concluded that the gravels were not older 
than Cretaceous nor younger than Lafayette, and was in- 
clined to believe that they are late Tertiary in age. For 
unstated reasons most recent writers have followed Win- 
chell and tentatively assigned a Cretaceous age to the high- 
level gravels and the plain on which they lie. Perhaps the 
reason is that marine Cretaceous rocks in western Iowa 
and Minnesota lie on a base of slight relief and bevel the 
same southwest dipping formations as occur in the Drift- 
less Area. 

After having spent part of a field season in southeastern 
Minnesota, assisted by Professor Leroy Patton, the writer 
is strongly inclined to favor the Tertiary age of the plain, 
for the following reasons : (1) The gravels of the Driftless 
Area are dissimilar from the rocks which carry Cretaceous 
fossils in Minnesota and from certain deposits of stratified 
gravels in Minnesota believed to be related to or derived 
from the Cretaceous rocks. Near New Ulm, Brown County, 
there is an exposure of stratified high-level gravels inter- 
bedded with sand and clay. The surface rock at this place 
is regarded as Cretaceous. The stratified deposit itself may 
be Cretaceous but might easily have been locally derived 



1. Winchell, N. H., Geol. and Nat'l Hist. Surv. Minn., Vol. I, pp. 309-310 ; 353-356. 

2. Salisbury. R. D., Jour. Geol., Vol. Ill, pp. 655-667. 



122 IOWA STUDIES IN NATURAL HISTORY 

from the Cretaceous. The latter seems quite probable for 
the reason that the Cretaceous deposits in this district con- 
tain pieces of gravel similar to the high-level gravel and 
also chalky particles which appear in the stratified deposits. 
The latter particles, however, could not have stood much 
transportation and are of themselves a strong argument for 
the local derivation of the high-level gravels. Other material 
derived from the Cretaceous in the earlier stages of the dis- 
section of the Cretaceous surface might have become wide- 
spread as stream gravels on the old surface of the pene- 
plain. (2) It should be noted that although Winchell may 
have been correct in his conjecture that certain gravels des- 
cribed by him were locally derived from Cretaceous de- 
posits, it does not follow as a corollary that the time of 
derivation was Cretaceous and that therefore any surface 
upon which these gravels lie is Cretaceous. In WinchelFs 
report 1 he distinctly states his belief that the gravels which 
he here describes were placed in position "by drift forces." 
Whether he meant that they were Cretaceous deposits re- 
worked during the Pleistocene period by a glacier is not 
clear. Certainly they are not glacial, but undoubtedly they 
were derived from the Cretaceous deposits revealed by post- 
Cretaceous streams. Winchell seems to have believed that 
at least some of the gravel deposits in Minnesota were of 
post-Cretaceous age. The writer believes that the high- 
level gravels of the Driftless Area, nowhere associated with 
sands, silts, or clays, are post-Cretaceous, though perhaps 
derived partly from Cretaceous formations containing 
gravel layers or levels. (3) WinchelFs conclusions were 
with regard to local and isolated cases only and had no ref- 
erence to gravel deposits of similar nature found in local- 
ities not suggesting a local derivation. (4) The Dodgeville 
plain constituting a stratigraphic base for the gravel has 
never been traced and found to underlie Cretaceous rocks 
but on the contrary its altitude in Minnesota is such as to 
cause it to bevel the Cretaceous. (5) The gravels extend 
far beyond any known Cretaceous and occur extensively 
where there is not the slightest indication of Cretaceous age. 

lT^Winchell, N. H., Geol. and Natl Hist. Surv. Minn., Vol. I, p. 309. 



EROSIONAL HISTORY OF DRIFTLESS AREA 123 

(6) The gravels of the Driftless Area are strikingly similar 
to the Tertiary gravels of the Gulf region. (7|), There are 
numerous patches of similar deposits south of the glaciated 
area and beneath the drift which seem to connect the gravel 
formation of the Driftless Area with the Tertiary deposits 
of the Gulf Coast. (8) The Dodgeville plain on which the 
gravels lie slopes south toward the Tertiary deposits rather 
than west toward the Cretaceous. (9) Salisbury's inter- 
pretation has been in print for a quarter of a century and 
all new discoveries seem to corroborate his tentative conclu- 
sions. (10) All patches of gravel between the Driftless Area 
and known Tertiary deposits occupy summit areas in the top- 
ography. (11) If the base of the Tertiary deposits were 
projected north it would coincide roughly with the Dodge- 
ville plain. (12) The base of the Tertiary deposits is in 
itself a peneplain. (13) The Tertiary gravels are known 
to lie on a raised peneplain in the southern Appalachians 
and elsewhere. These facts seem to the writer almost con- 
clusive of the Tertiary age of the Dodgeville plain. Whether 
the plain is Eocene, Oligocene, Miocene, or Pliocene in age 
cannot be determined, for the precise age of the Tertiary 
gravels on the Gulf Coast is in doubt. It is believed, how- 
ever, to be late rather than early or middle Tertiary. 
The Age of the Lancaster Plain 

The Lancaster plain is clearly younger than the Dodge- 
ville plain and is probably therefore late Tertiary or Pleis- 
tocene in age. It has been generally understood that the 
great uplift in the interior of the United States came at the 
close of the Tertiary, in the epoch known by some as the 
Ozarkian. Because the greatest movement which affected 
the Driftless Area uplifted and started the dissection of the 
Lancaster plain this plain has been most generally referred 
to the late Tertiary. 

The writer is not certain that the Lancaster plain is not 
Tertiary in age, but he wishes to present some evidences 
that it was not completed and uplifted before the first ice 
invasion. The work of the writer during several years, and 
the work of A. J. Williams 1 has shown that there is old 



1. Williams, A. J., Manuscript so far unpublished. 



124 IOWA STUDIES IN NATURAL HISTORY 

drift extending eastward beyond the mapped border of 
Kansan drift on the west side of the Driftless Area in Iowa, 
almost and in many places quite to the Mississippi river. 
There is also at least one area of this upland drift in Illi- 
nois 1 . Whereas the Kansan drift within the mapped area 
lies at all levels of the bedrock topography from the tops of 
the highest hills to the bottoms of the deepest valleys, this 
drift beyond the Kansan border, with the exception of a 
tongue of supposedly Kansan drift near McGregor, is found 
most abundantly on the Lancaster plain, sparingly on the 
slopes above the Lancaster plain, and still more sparingly 
on the Dodgeville plain. Of the several hundred isolated 
remnants of this drift which are now known, not a single 
patch is in place in the valleys below the Lancaster plain. 
If this drift were Kansan and deposited after the deep val- 
leys were cut, it would seem difficult to explain why it would 
all have been removed from the valleys and valley benches 
so that the drift now extends farther east on the narrow 
divides than in the broad, open, terraced valleys. Still more 
difficult would it be to explain, if the deposition of this drift 
took place after the valleys were cut, how a glacier thick 
enough to fill valleys 600 feet and more deep so as to spread 
over the divides could have advanced, deposited this drift 
and retreated without so having changed the profiles of the 
valleys or so having modified the divides or so having 
marked the rock surfaces as to have left some trace on the 
surface below the Lancaster plain. When it is recalled that 
almost wherever known this oldest Pleistocene drift lies on 
high divides or benches above valleys believed to have been 
cut after the deposition of the drift, as in New Jersey 2 , 
Montana 3 , and the San Juan mountains of Colorado 4 , there 
is nothing new nor radical in the supposition that in the 
Driftless Area also, it antedated in its deposition the for- 
mation of the deep valleys. This upland drift has the ap- 
pearance of great age but perhaps not of greater age than 

1. Trowbridge, A. C. and Shaw, E. W., Bull. III. Geol. Surv.. No. 26, p. 87. 

2. Salisbury, R. D., Ann. Rept. State Geologist of New Jersey for 1893, pp. 73-123, 
especially p. 87. 

3. Alden, W. C. and Stebinger, Eugene, Bull. Geol. Soc. Am., Vol. 24, pp. 529-572. 

4. Atwood, W. W. and Mather, K. F., Jour. Geol., Vol. 20, pp. 385-409. 



EROSIONAL HISTORY OF DRIFTLESS AREA 125 

the Kansan drift, where it is thin. Where either drift is 
thin, it has been brought to its limits of weathering. 

There is then some evidence, which seems to the writer 
to be strongly indicative, if not conclusive, that this drift, 
in a district which has been called driftless, is pre-Kansan 
in age, and that it was deposited while the Lancaster plain 
was still intact and before the deep valleys were formed. 
Otherwise, why should there be no patches of the drift in 
the valleys? And why should the valleys show not the 
slightest indication of having been glacially worn? The 
Kansan drift seems clearly enough to have been deposited 
after the valleys were formed. 

The above evidence seems to justify the interpretation, at 
least as a working hypothesis, that the Lancaster plain was 
intact at the time of the pre-Kansan ice invasion, but that 
it was uplifted and partly dissected before the Kansan 
epoch. Leverett 1 objects to this interpretation and cites 
the presence of pre-Kansan drift in the bottoms of deep 
rock-bound valleys in Wisconsin and southeastern Iowa. So 
far as the writer has been able to investigate the evidence, 
he finds it inconclusive. The writer's interpretation is 
strengthened by E. W. Shaw 2 , whose recent work in the 
Ozark district seems to show that the main uplift and the 
main development of the Mississippi valley there took place 
during the early Pleistocene, rather than at the close of the 
Tertiary as was previously supposed. 

Accepting the above interpretations of the ages of the 
Dodgeville and Lancaster plains, at least as probabilities, 
the probable dates of diastrophic events and erosion cycles 
are easily determined and are stated in the following sum- 
mary of events. 

SUMMARY OF EVENTS 
The first step in the history of the surface of the Drift- 
less Area was the final emergence of the surface from the 
sea and the formation of an anticline with its axis running 
through La Crosse and its south limb forming a great 

1. Personal communications and oral discussions in the field. 

2. Personal communications to the writer. 



126 IOWA STUDIES IN NATURAL HISTORY 

monoclinorium which extends far beyond the boundaries of 
the Driftless Area to the south and southwest. This move- 
ment left the surface high above the level of grade, with a 
stream divide on the axis of the fold. This event took place 
after the Niagaran epoch of the Silurian period and prob- 
ably after the Pennsylvanian period, but before the Creta- 
ceous. The date may be set roughly at the close of the 
Paleozoic era. 

Following its initiation, the surface was eroded in one or 
more cycles and was brought to the condition of a plain 
with a relief of less than 200 feet, the Dodgeville plain. The 
cycle was not complete, but a stage at least as late as early 
old age was reached. The divide at La Crosse was probably 
obliterated before the close of this cycle. The stage in the 
history of the region was probably brought to an end at 
some time during or at the close of the Tertiary period. 

Probably in late Tertiary time the gravel-strewn Dodge- 
ville plain was uplifted almost uniformly to the amount of 
approximately 180 feet. 

The uplift mentioned in the last paragraph inaugurated 
a new cycle of erosion known as the Lancaster cycle, which 
continued probably until the advance of the pre-Kansan 
glacier in the earliest part of Pleistocene period, by which 
time a second peneplain, the Lancaster plain, had been 
formed. Neither was this cycle of erosion complete. How- 
ever, the surface at this time was much more nearly flat 
than the present surface. The surface doubtless lacked 
something of having gone so far in its stage of reduction 
as was the case during the Dodgeville cycle. 

The Lancaster erosion cycle was interrupted most likely 
at some time soon after the retreat of the pre-Kansan 
glacier in the early Pleistocene, by a diastrophic uplift with- 
out tilting or warping, amounting to 600 feet or more. This 
movement raised the Lancaster plain to levels high above 
grade and inaugurated a third cycle of erosion. 

The details of the post-Nebraskan, pre-Wisconsin history 
of the Driftless Area are not known, but the history seems 
to have been one of erosion interrupted locally and tern- 



EROSIONAL HISTORY OF DRIFTLESS AREA 127 

porarily by the deposition of at least two bodies of glacial 
drift on the borders of the area. Deep valleys appear to 
have been cut before the advance of the Kansan glacier and 
the deposition of a thin body of Kansan drift on the west 
border. The valleys of Pecatonica and Apple 1 rivers had 
been cut to depths below their present bottoms by the time 
of the Illinoian (?) ice invasion from the east. 

Some time before or during or immediately after the 
Wisconsin glacial epoch, when the valley trains were de- 
posited in the Mississippi and Wisconsin valleys, there ap- 
pears to have occurred a subsidence of the surface amount- 
ing to about 180 feet and perhaps accompanied by a tilting 
of all older graded surfaces slightly to the south. The sub- 
sidence rendered it impossible for the Mississippi and its 
tributaries to cut back to their original levels. If tilting 
occurred the gentler slope of the present flood plain as com- 
pared with all previous gradients is explained. 

After the withdrawal of the Wisconsin glacier the Mis- 
sissippi river and its tributaries began to excavate their 
valleys by the removal of the fluvio-glacial debris but they 
reached grade 30 or 40 feet below the original top of the 
deposit and 180 feet on the average above its bottom. Hav- 
ing reached grade, the streams have all developed valley 
flats in the soft material deposited by waters during the 
Wisconsin epoch. 



1. Trowbridge, A. C. and Shaw, E. W., Bull. 111. Geol. Surv. No. 26, pp. 95-99. 



1 "■ 

" i ' ' *~- ' 

FIRST SERIES NO. 43 FEBRUARY 15, 1921 

UNIVERSITY OF IOWA 
STUDIES 



STUDIES IN NATURAL 
HISTORY 

VOLUME IX NUMBER 2 

THE HESPERIOIDEA OF 

AMERICA NORTH 

OF MEXICO 



by 
ARTHUR WARD LTNDSEY 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 

Issued monthly throughout the year. Entered at the post office at Iowa City, Iowa, 

as second class matter. Acceptance for mailing at special rates of postage provided 

for in section 1103 ? Act of October 3, 1917, authorized on July 3, 1918. 




At 

lies per fa 

Xenophan 

Hesperic", 



10. 
1 I. 



tonopsis pythoi 

itaureae Ramf). 

ti-yxus ('v., ■; / 

ccfoTiun Boisd 
Chioides /.ilpa But I, S, ""' 
Uesperia ericctorum Boisd.. 
Hesperia philetas Krhv., :'' 
Kami* ttn-aso Hbn., 9 
Pamphila ncvada Scud, ?. 
Melanthes brunnea H'.-S., d" 
Pamphila comma, race Colorado Send 



, V 

lor surface 
under surface 



9, under surface 



Pamphila viridis Kdw., rf, under surface (1111 . f „« 

Pamphila comma, race ore^onia Kdxv.. ?. under smfacc 



*w 






UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 

Professor Charles Cleveland Nutting, M.A., Editor 



CONTINUATION OP BULLETIN FROM THE LABORATORIES OF NATURAL HISTORY 
OF THE STATE UNIVERSITY OF IOWA 



VOLUME IX NUMBER ?! y 



THE HESPERIOIDEA OF AMERICA 
NORTH OF MEXICO 

A Generic Revision and Synopsis of the Species 

by 
ARTHUR WARD LINDSEY, Ph.D. 



' PUBLISHED BY THE UNIVERSITY, IOWA CITY 



THE HESPERIOIDEA OF AMERICA 
NORTH OF MEXICO 

Since the time of the early writers who were satisfied to place 
their skippers in the two genera, PamphUa and Hesperia, the 
classification of these insects has been in a more or less chaotic 
state. The two old genera can readily be subdivided, but the 
structures of the skippers which are useful in their classification 
are of a peculiarly unstable character and have therefore proven 
a stumbling block to those who have attempted such subdivision. 
This is due to the fact that very few of our species are struc- 
turally identical, as a result of which one division has led to 
another until we have reached the deplorable state where, to be 
consistent, we must either lump extensively or split still more 
finely, with most lepidopterists in favor of the former. In the 
following pages I have attempted to rearrange our species and 
reorganize our genera to eliminate the confusion which has at- 
tended the group in North America, while bearing in mind both 
the convenience of the classification and the opinions of the 
learned authors of many genera for which I have been unable to 
see any necessity. Undoubtedly I have erred in some points, 
especially in the case of the numerous species found in the south- 
west which belong to genera more typical of the Central Ameri- 
can fauna, but I believe that the examination of a more complete 
collection of exotic species will clear up many obscure points for 
which I have been able to offer only a tentative solution. 

In the course of my work I have had occasion to ask informa- 
tion of Prof. H. F. Wickham, Dr. J. McDunnough, and Dr. 
Henry Skinner. Dr. Skinner has also supplied me with a num- 
ber of specimens which I could not otherwise obtain, and Prof. 
Wickham has lent a number of books from his private library. 
Dr. Barnes of Decatur, 111., has very generously allowed me the 
freedom of his fine collection and library, and also supplied me 
with many specimens for study. Mr. R. A. Leussler of Omaha 

(3) 



4 IOWA STUDIES IN NATURAL HISTORY 

has given me specimens of several species which I had been un- 
able to secure, and Mr. Nathan Banks has kindly examined the 
collection at Cambridge for certain material and furnished 
transcripts of several necessary descriptions not in my posses- 
sion. Mr. Gerhard of the Field Museum made it possible for 
me to spend several profitable hours in the examination of the 
Strecker collection in that institution. To all of these men I 
wish to express my gratitude for their valuable assistance. 

The first step toward a rational classification of the skippers 
was made by Scudder in 1874 * when he proposed the division of 
the family, as he regarded it, into two tribes, the Hesperides and 
Astyci. These represented approximately the genera Thymele 
and Pa/mphUa of Fabricius' classification in Illiger's Magazine 
in 1807. Scudder based his tribes on the secondary sexual char- 
acters of the males and characters found in the early stages. 

This paper was followed in 1878 by Mabille 's, work on the 
Hesperiidae in the Brussels museum. 2 Mabille adopted the tribes 
proposed by Scudder but subdivided them into several minor 
groups each. Scudder later expressed his approval of these 
divisions for the Hesperidi but reserved his judgment of the 
Astyoi. 3 Many of Mabille 's groups are not represented in our 
fauna; the others have been the subject of very little dispute. 

In the same year there appeared a paper by Burmeister 4 in 
which the family is divided into four tribes. I am familiar with 
this paper only through the remarks of Scudder in the Butter- 
fles of New England, but these are quite sufficient to show that 
none but historic interest attaches to the rather remarkable ar- 
rangement proposed. 

A year after this Speyer produced a brief work 5 in Germany 
wherein we find the first suggestion of the systematic importance 
of the position of vein five of the primaries. This suggestion 
furnished the necessary complement to Scudder 's foundation for 
the major subdivisions of the skippers, which are still in use. 

Nothing further of importance was done in the systematic 

iBull. Buff. Soc. Nat. Hist. I, 195, 1874. 

2 Ann. Soc. Ent. Belg. xxi, 12, 1878. 

3 Butt. New Eng. II, 1372, 18. 

4 Desc. Phys. Rep. Arg., Lep. 245, 1878. 

5 Stett. ent. Zeit. xl, 477, 1879. 



HESPERIOIDEA OF AMERICA 5 

study of these insects until 1893, when Watson published 6 his 
" Proposed Classification of the Hesperiidae," which is prac- 
tically the classification now in use. Watson divided the family 
into three subfamilies, the Pyrrhopyginae, Hesperiinae and 
Pamphilinae, equivalent to the Pyrrhopygini of Mabille and the 
two tribes of Scudder. He further subdivided the Hesperiinae 
into two groups and the Pamphilinae into three. Group C of 
the Pamphilinae is wholly oriental and African. The others 
correspond to the similar divisions of Scudder in part. As Wat- 
son was working on the collection in the British Museum where 
Megathymus was placed in the Heteroeera, he merely mentioned 
the genus to indicate that if placed in the Hesperiidae it would 
form an additional subf amity. 

At this time Godman and Salvin had been publishing for six 
years parts of the three volumes on Rhopalocera of the Biologia 
Centrali-Americana. The first signature on the skippers ap- 
peared a few months before Watson 's revision, but the work was 
not completed until 1901. The subfamilies are those of Watson 
and the Hesperiinae are divided as in his classification, but the 
Pamphilinae, worked up by Godman after Salvin 's death, are 
divided into eight groups. These are not wholly acceptable, but 
they suggest an improvement over the two groups of other writ- 
ers. The chief systematic interest of the Biologia lies in the 
number of genera described, the excellent plates, and the great 
value of the work for specific identifications. 

But one other paper, Mabille 's monumental "Famille Hes- 
peridae," 7 has been written on the Hesperioid fauna of the 
world since the earliest times. In this work Mabille uses the 
same arrangement as that of Watson, excepting the establish- 
ment of the subfamily Ismeninae to take the place of Watson's 
Group C of the Pamphilinae, and the definite placing of Me- 
gathymus in the subfamily Megathyminae. 

There remains to be mentioned Dyar's " Review of the Hes- 
periidae of the United States. ' ' 8 This brief paper is the only 
one ever published on the skippers of this country, and in spite 
of omissions and commissions of an unusual nature it has filled a 

6 Proc. Zool. Soc. London, 1893, 3-132, pi. i-iii. 

7 Genera Insectorum xvii, 1903-4. 

8 Journ. N. Y. Ent. Soc. XIII, 111-141, 1905. 



6 IOWA STUDIES IN NATURAL HISTORY 

great need of systematic lepidopterists. It was intended, as the 
name implies, merely as a synopsis of the genera and species and 
follows the "Famille Hesperidae" with comparatively few 
changes. 

These works are the foundation of our present system of class- 
ification. Many others with a wider range have contributed to 
our knowledge of the skippers but in none of these is any work 
of importance on the gross classification attempted. 

It will be noted in the preceding sketch of the history of the 
skippers that they have been treated as the family Hesperiidae, 
equivalent to the several families of butterfles with which they 
have been associated. This position is the only one to which 
they have been widely assigned, though a number of writers have 
given them superfamily rank. E. Reuter carries this a step 
further and proposes a distinct suborder under the name Grypo- 
cera, 9 equivalent to the Rhopalocera and Heterocera, while 
Spuler does likewise, but applies the name Netrocera. 10 This re- 
opens the question of suborders, for if we accept Comstock's 
Frenatae and Jugatae the two older groups can no longer occupy 
this rank and must be either reduced or discarded. I regard 
them as natural groups though I am inclined to agree with Corn- 
stock ? s subdivision. The Rhopalocera and Heterocera may con- 
veniently be designated as series. In this arrangement I cannot 
accept Reuter 's Grypocera as indicative of the true relations of 
the skippers, but the name is still given some use in Europe. 
There are many points, however, in which the skippers show 
more primitive development or peculiar uniform specialization 
which distinguish them from the true butterflies, and the most 
natural arrangement appears to be that of Comstock 1X in which 
they are made a superfamily equivalent to the butterflies proper, 
According to our present nomenclature this superfamily should 
be known as the Hesperioidea. The following synopsis indicates 
the foundation of this classification for the suborder Frenatae. 
Frenatae 

Series Heterocera. Antennae rarely clavate. When clavate 
usually more or less pectinate or ciliate. Hind tibiae usual- 

9 Act. Soc. Faun. Flor. Fenn. xxii. 

10 Spuler, Die Schmetterlinge Europas I, 70, 1908. 
u Manual 364, 1895. 



HESPERIOIDBA OF AMERICA 7 

ly with two pairs of spurs; front legs normal. Frenulum 
present in many families. Venation of primaries general- 
ized or characteristically specialized. Pupa loose in cocoon, 
earthen cell or plant tissues. Superfamilies Sphingoidea, 
Saturnioidea, Bombycoidea and Tineoidea. 
Series Rhopalocera. Antennae usually strongly elavate ; nev- 
er pectinate or ciliate. 

Superfamily Hesperioidea : Pupa suspended in a slight 
cocoon. Hind tibiae rarely with less than two pairs of 
spurs; front legs normal. Frenulum absent. Primaries 
with twelve veins, all free. (All five branches of radius 
present and from cell according to Comstock's system.) 
Superfamily Papilionoidea : Pupa naked, usually suspend- 
ed from silken attachments and specialized for conceal- 
ment. Hind tibiae with only the terminal pair of spurs; 
front legs in higher families greatly reduced. Frenulum 
absent. Primaries with less than twelve veins or with 
some stalked. 
In the Hesperioidea we have two families, the Hesperiidae and 
Megathymidae. The second includes only the genera Megathy- 
mus and Aegiale, and is equivalent to the subfamily of other 
writers. The first includes all other skippers. The Megathymi- 
dae are very closely related to the Pamphilinae, and some stu- 
dents regard them as a highly specialized branch from the same 
parent stock. The fact that the boring habit of the larvae is 
apparently acquired lends color to this opinion, but I cannot 
regard the small head as a necessary accompaniment of the bor- 
ing habit. Rather than assume an elaborate process of evolution 
for the reduction of such a specialization as the large head, I 
regard the Megathymidae as a line separated from the parent 
stock of the Pamphilinae before the increase in size of the head, 
and proceeding by parallel development to a point of higher 
specialization of similar structures. 

The three subfamilies of Hesperiidae are easily distinguished, 
apparently natural groups. The only question regarding them 
is that of relative position, and the present arrangement of the 
Hesperiinae between the Pamphilinae and Papilionoidea is favor- 
ed by most of the evidence, though in the structure of the imago 



8 IOWA STUDIES IN NATURAL HISTORY 

they are more primitive than the Pamphilinae. The close rela- 
tionship of the Pyrrhopyginae with the Hesperiinae and of the 
Megathymidae with the Pamphilinae leads to their being placed 
at the beginning and end of the superfamily respectively. The 
result is a linear series which is not entirely satisfactory, but 
since no linear series can represent true phylogenetic relations 
this must be accepted as the best possible, and it does, at least, 
correctly indicate the general relations of the several major 
divisions. 

The separation of genera has been the most troublesome phase 
of the study of skippers since Hiibner's classification was first 
amplified. I have come to the conclusion that the intermediate 
position of the group, together with the apparently transitional 
state of many of the structures, is accompanied by a greater 
blending of forms than has been recognized in the past, and that 
the normal genus may present a wide variation of structure, 
provided that a transition between the extremes be present in the 
included species. This is nicely illustrated by Thanaos, Hesperia 
and Poanes (sensu B. & McD., Check List). In Thanaos we 
have a group of insects of very similar habitus which no one has 
ever divided, but within the genus are to be found differences 
in structure which have been made to separate three genera in 
other cases. The neuration, shape of the wings, palpi and sec- 
ondary sexual characters very nearly run the gamut of variation 
found in Group B of the Hesperiinae. Hesperia is similar but 
shows an even greater range of variation in the antennal club, 
shape of the wings, and in the palpi. In fact this variation is so 
great as to occasion some doubt of its unity, but it is impossible 
to divide the genus without separating .some species whose rela- 
tionship is apparent. 

The matter of secondary sexual characters as a basis for the 
separation of genera is the greatest bugbear of systematists in 
this family. Godman and Salvin and Mabille have contributed 
abundantly to the confusion of genera so based, and in many 
cases these genera cannot be separated by other means. As far 
as I am aware the only definite stand taken upon the question is 
that expressed by Watson in his revision.* He says: "With 

* Since writing this I have found a quotation from Dr. P. L. Sclater by Col. C. 
Swinhoe in defense of genera based on secondary sexual characters (Ann. & Mag. 
Nat. Hist, (vn), in, 108, 1899). 



HESPERIOIDEA OF AMERICA 9 

regard to the vexed question of the generic importance of male 
secondary sexual characters, the conclusion which has been 
forced upon me is that, in any particular genus in which male 
secondary sexual characters are found, the particular male char- 
acter (be it costal fold, discal stigma, or tuft of hairs) may be 
either present or absent in different species of that same genus, 
but is never replaced by a character of different structure." 

This seemd by far the most satisfactory, attitude to adopt, 
though it is necessary to understand that in cases such as 
Thanaos and Hesperia two or three such characters may be pres- 
ent or absent in various combinations in the several species. In 
my work, rather than carry the splitting of genera further, I 
have unhesitatingly followed Watson's conclusion. This has re- 
sulted in the dropping of a number of familiar genera, but I 
think that once we are accustomed to the change it will render 
our classification more convenient and more useful, as well as 
more natural. Some change is demanded for the sake of con- 
sistency, and since our genera have already been carried beyond 
the point of usefulness, " lumping" is the only desirable change. 

The structures of systematic value in the Hesperioidea are 
found in all parts of the body. The size of the head serves to 
distinguish the two families, and its appendages, the palpi and 
antennae, offer a means of separating many genera. The palpi 
vary in length and position and the relative size of the second 
and third joints is useful, but it is necessary to look at all of 
these things in a general way. For example, in Pholisora as 
here treated we find great variation in the vestiture of the palpi 
and in the relative length of the third joint, but throughout the 
genus long palpi with smooth deep scaly vestiture, an oblique 
second joint and a porrect third joint with long scales are pres- 
ent. Thanaos has palpi of a similar form but with shaggy vesti- 
ture. The third joint in some genera is long, slender and ver- 
tical. 

The antennae have a characteristic slender tip which has been 
aptly termed the apiculus. This varies from the tiny point 
found in PamphUa to the long one of Goniwrus, and has been 
entirely lost in some genera. This modification has apparently 
taken place by two distinct lines of evolution, first the loss of the 
apiculus by gradual reduction and second by the thickening and 



10 IOWA STUDIES IN NATURAL HISTORY 

fusion of the structure with the elub. The first has apparently- 
taken place in the Pamphilinae and the second in the Hesper- 
iinae. The relation of the length of the apiculus to the thickness 
of the club has been used extensively to separate certain genera 
of the Pamphilinae but I find that its value is limited. It ijs 
variable in most species, and only where extremely short or ex- 
tremely long is this variation negligible. In such species as 
vema the apiculus is sometimes longer and sometimes shorter 
than the thickness of the club and is always difficult to measure 
with satisfactory accuracy. The length of the entire antennae 
measured in proportion to some other part of the insect is useful 
to distinguish a few genera of our fauna. 

The legs offer three important characters, viz., the presence or 
absence of the epiphysis on the front tibiae, the presence or ab- 
sence of spines on the mid tibiae and to a certain extent their 
form, and the number of pairs of spurs on the hind tibiae. The 
epiphysis does not concern us in a study of the North American 
fauna and the spurs on the hind tibiae characterize only one 
genus, but the spinulation of the mid tibiae is useful in several 
eases and in spite of some evidence to the contrary, I believe that 
it is a good character, at least to the extent used in this paper. 

The wings vary greatly in shape, sometimes in a striking way, 
as in Eantis, Systaseu and Goniurus. In certain others, as Atry- 
tonopsis, they have a distinctive form which is less useful because 
less pronounced in the female and difficult to characterize. The 
neuration is of comparatively little use beyond a few conspicuous 
features, for it is impossible to pick a reasonably long series of 
related species without finding some transition in all of the 
salient features. In spite of this I have made use of the position 
of vein 11 of the primaries to separate Chiomara from Thanaos, 
but in this ease there seem to be other grounds, and the one vein 
furnishes a convenient and apparently reliable corollary. The 
distance between the bases of veins 6 and 7 of the primaries of 
Pholisora is greater than in most other genera. The relation of 
vein 5 to 4 and 6 in the primaries distinguishes the Megathy- 
midae and most Pamphilinae from the other skippers, and helps 
to separate some genera. The position of veins 2 and 3 of the 
primaries is another character which must be used with caution, 
for these veins vary in closely related species and can be depend- 



HESPEEIOIDEA OF AMEEICA 11 

ed upon only in extreme cases. The neuration of the second- 
aries is scarcely worthy of notice, though some exotic genera are 
characterized by the presence of vein 5, which is usually absent 
or very weak. 

The abdomen is of little service, though it aids in distinguish- 
ing the genera of group A of the Pamphilinae from certan Hes- 
periinae in that it projects beyond the secondaries in the former 
and scarcely reaches their anal angle in the latter. 

The male secondary sexual characters in the Hesperiinae con- 
sist of the costal fold on the primaries, tuft (always proximal 
in our species) on the hind tibiae, tuft on the upper surface of 
the secondaries and the two lobes found at the base of the abdo- 
men on its ventral surface in Hesperia. In the Pamphilinae the 
only form found in the North American fauna is the brand or 
stigma on the disk of the primaries. While I agree with Wat- 
son's treatment of these characters I believe that the great dif- 
ference in form between some of the stigmata indicates suffi- 
ciently different development of the species possessing them to 
warrant their generic separation. Fortunately in our fauna this 
character can be supplemented by others. It is necessary to 
guard agains splitting on this basis, for many stigmata which 
are superficially different may easily be seen to follow in their 
fundamental structure a single type. 

The genitalia, especially of the males, are of great value in 
making specific determinations, and similarity of genitalia often 
affords an index of generic relationship. I have found several 
apparent contradictions to the latter statement, and am there- 
fore inclined to use it very cautiously until more is known about 
the skippers, but still I hesitate to include in the same genus 
species whose genitalia are of widely different forms. 

In attempting to work out the phylogeny of our existing 
speces I have come to the conclusion that the subfamily Ismeni- 
nae, made up entirely of old world species, represents the most 
primitive existing form. The entire subfamily is characterized 
by the upturned, appressed second joint of the palpi, very sim- 
ilar to that of the Hesperiinae of group A, and the long, porrect 
third joint which is unique. The antennae have a short shaft 
and a long, moderately thick club with a long apiculus which 



12 IOWA STUDIES IN NATURAL HISTORY 

is never sharply recurved. The hind tibiae of the males are 
provided with a tuft attached at the proximal end and lying 
along the upper edge of the joint in a groove formed of strong 
scales. Vein five of the primaries is intermediate between veins 
four and six. From these structures we may assume that the 
immediate ancestors of the skippers had antennae enlarged at 
some distance proximad of the distal end, leaving the terminal 
portion riender, and that vein five of the primaries in these 
insects had not yet formed a definite connection with either of 
the adjacent veins. From such forms evolution has proceeded 
with the permanent reflection of the apiculus by either a curve 
or a sharp bend. (I can construe the reflexed club of the Pyr- 
rhopyginae only as a further development of the Hesperiid an- 
tenna, though this does not seem a satisfactory explanation). 
En addition the apiculus has been reduced as already mentioned 
and various slight specializations have taken place. The wings 
of the Hesperiinae have changed only in the variably complete 
loss of vein five of the secondaries and the lengthening of the 
cell in group A, while in the Pamphilinae vein five of the pri- 
maries, has formed a definite connection with the median stem 
(English system; cubitus of Comstoek and Needham), as also is 
the ease with the Megathymidae. Following these lines I have 
drawn up the following diagram which I believe will indicate 
better than a written discussion the relations and phylogeny of 
the genera used in this work. The arrangement undoubtedly 
has its faults, but I believe that it corrects a number of features 
of former arrangements which were more or less unnatural. In 
the main it adheres to the order of genera which has been in 
common use. 

Superfamily HESPERIOIDEA 
Antennae elavate, in a few genera with the club very slender. 
Club usually with a slender tip called the apiculus. Palpi 
variable, usually relatively large and thick, upturned to porrect. 
Head wide, eyes large and far apart, lashed. Insertion of an- 
tennae near eyes. Body stout, slender in a few genera. Wings 
relatively smaller than in the Papilionoidea and with very strong 
venation in most genera. Primaries with twelve veins, all free; 
cell open or weakly closed. One anal. Secondaries with eight 



HESPERIOIDEA OF AMERICA 



13 



-Pyrrhopyginae 



rl 



j 



W 



> 



— Phocides 
— Polygonus 
— Nascus 
— Proteides 
— Epargyreus 
— Goniurus 
— Chioides 
— Codatraetus 
— Telegonus 
— Achalarus 
— Cecropterus 
— Thorybes 
— Cabares 
— Phoedinus 
— Cogia 
• — Plestia 

— Timochares 
— Grais 
— Thanaos 
— Chiomara 
— Melanthes 
— Xenophanes 
— Eantis 



— Pholisora 
— Hesperia 

— Carterocephalus 



-Butleria 



A 



-MEGATHYMIDAE 



. — Ancyloxypha 
^l—Oarisma 
— Adopaea 
— Copaeodes 

— Chaerephon 
— Pamphila 
— Hylephila 
— Atalopedes 

Augiades 

Polites 
— Catia 
— Poanes 
— Atrytone 
— Atrytonopsis 
— Oligoria 
— Lerema 
— Mastor 
— Amblyscirtes 
— Epiphyes 
— Lerodea 

y I — Thespieus 
— I — Calpodes 
I — Prenes 



14 IOWA STUDIES IN NATURAL HISTORY 

or nine veins, five usually absent ; cell open. Two anals. Front 
legs normal, tibiae usually with the epiphysis present (in all 
North American genera). Middle legs with one pair of spurs 
on the tibiae and with or without spines. Hind legs with two 
pairs of spurs, or with only the distal pair in some genera. 
The two families are based on the following characters: 
Family HESPERIIDAE : Head nearly as wide to wider than 
thorax. Hind tibiae usually with two pairs of spurs. Pal- 
pi moderate to large. Larvae external plant feeders. 
Family MEGATHYMIDAE : Head narrower than thorax. 
Hind tibiae with one pair of spurs. Palpi rather small. 
Larvae borers in plant stems. Imagines larger than most 
Hesperiidae, heavy bodied and strong of flight. 

Family HESPERIIDAE 
Characters of the superfamily, distinguished from the Me- 
gathymidae as shown in the preceding synopsis. The North 
American species fall into three subfamilies which may be sep- 
arated by the following key, which also deals with the groups 
into which the subfamilies are divided. 

Key to subfamilies and groups 

1. Club of antennae large, entirely reflexed. . . .pyrrhopyginae 
Club variable, never entirely reflexed 2 

2. Vein 5 of primaries not curved at base, usually about inter- 
mediate between 4 and 6. Mid tibiae without spines 

HESPERIEST AE 3 

Vein 5 curved at base, arising nearer to 4, or with the mid 
tibiae spined pamphilinae 4 

3. Cell of primaries more than two-thirds as long as wing or 
antennae with a slender reflexed or recurved apiclus 

Group A 

Cell two-thirds or less. Club curved, blunt or fusiform, but 
never with a slender apiculus Croup B 

4. Vein 5 intermediate, straight. Club blunt. Palpi porrect 

Group A 

Vein 5 curved at base, nearer to 4. Palpi not porrecjt. 
Group B of authors 5 



HESPERIOIDEA OF AMERICA 15 

5. Third joint of palpi long slender and vertical. Antennae 

short with the club blunt Group B 

Third joint small or antennae with a slender apiculus 

Group C 

Cell of primaries two-thirds as long as wing, usually with a 
recurrent vein or a vestige of it Group D 

Subfamily PYRRHOPYGINAE 

This subfamily includes a large number of South and Central 
American species of which only one, araxes, occurs within our 
territory. The large antennal club, bent back along the shaft 
or recurved, is typical of all the species. In other respects their 
structure agrees to a great extent with that found in group A 
of the Hesperiinae. The cell of the primaries is apically pro- 
duced with the discocellulars outwardly concave, and is about 
two-thirds as long as the wing. The discocellulars are weak, but 
clearly traceable. Vein 5 is approximately intermediate in the 
primaries, and absent in the secondaries, though found in a few 
exotic genera. 

Aractes has been included in the genus Pyrrhopyge by all writ- 
ers with whose works I am familiar, but the difference in habitus 
and the form of the secondaries have led me to remove it. Wat- 
son's diagnosis of his genus Microceris (P. Z. S. 1893, 15) dif- 
fers in only a few points from the structures of araxes, but the 
type, variicolor, judging by the original description and figure, 
is not at all closely related. I am therefore basing a new genus 
on the points of difference between araxes and Watson's de- 
scription of Microceris. 

Genus APYRROTHRIX gen. nov. 
Similar to Pyrrhopyge. Differs from that genus in the more 
gently curved costa and more prominent apex of the primaries 
and the form of the secondaries. In Pyrrhopyge these appear 
to be longer through the cell than along the inner margin, and 
the outer margin is even or slightly concave between veins 2 and 
7. The abdomen usually equals or surpasses the anal angle of 
the secondaries. In araxes the secondaries are broad and full, 
and surpass the abdomen. The outer margin is deeply crenu- 
late, produced between veins 2 and 4 in the male and eonspieu- 



16 



IOWA STUDIES IN NATURAL HISTORY 




Fig. 1. Apyrrothrkc araxes 

Hew. a. CIiil) of antenna, b. 

Neuration 



ously so in the female. According to 
Watson veins 7 and 8 of the primaries 
of variicolor are short stalked, while in 
araxes they are free. Watson's figure of 
the neuration of his genus differs in a 
few points in the secondaries also, and on 
the whole the relationship seems to be 
rather with the typical species of Pyrr- 
hopyge than with araxes. Fig.l. 
Type: Ery aides araxes Hew. 

1. APYRROTHBIX ARAXES 

Erycides araxes Hewitson, Desc. Hesp. 2, 1867. 
Pyrrhopyga cyrillus Plotz, Stett. ent. Zeit, xl, 

529, 1879. 
Biologia Cent. -Am., Ehop. n , 252, pi. 73, ff 14, 

15, 16, 1893. 
Holland, Butterfly Book 319, pi. xlv, f. 9, 

1898. 

Mexico. I have two bred specimens 
from southern Arizona which are very 

close to araxes but the typical form is not known to occur north 
of the boundary. 

la. race ARIZONAE 
Pyrrhopyge araxes, form arizonae G. & S., Biol. Cent.-Am., Bhop. n, 253, 

1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 201, pi. x, 1911. 

Dark marks on under surface of secondaries not well defined, suffused 
with ochreous. Outer margin of ochreous area diffuse. 

Arizonae occurs in Arizona in August and September. 

Subfamily HESPERIINAE 
Structure very diverse but always showing the characters 
mentioned in the key. Antennae varying in length, club flat- 
tened oval to extremely long and slender, with the distal half 
or less reflexed or recurved. Palpi with the second joint closely 
appressed and the third minute to long, large and porrect. Neu- 
ration fairly constant. Branches of radius variable in position. 
Vein 5 straight and about intermediate between 4 and 6, 2 varia- 
ble. Secondaries with position of 7 variable and vein 5 absent 
to weakly tubular at its outer end (Thanaos, some specimens), 



HESPERIOIDEA OF AMERICA 17 

usually marked by a fold. Mid tibiae without spines. Two 
pairs of spurs present on the hind tibiae in our genera. Sec- 
ondary sexual characters of the males: costal fold, tibial tuft, 
tuft on secondaries, and basal lobes on under surface of abdo- 
men. 

GROUP A 
Group A is more widely represented in South and Central 
America, and a number of our species are merely strays from 
more southern localities. The genera have been very incon- 
sistently treated in the past, and I am lumping a few of them 
which show a complete lack of constant structural differences 
with the exception of the costal fold. Several such as Cecrop- 
terus and Thorybes are very closely related but because of the 
very distinct form of the male genitalia I am retaining them, 
based on such characters as will serve for their separation. The 
group is distinguished by the length of the cell and the form 
of the antennal club. 

Key to the genera 

1. L. D. C. of primaries very long and curved Phacides 

L. D. C. normal 2 

2. Apiculus of antennae longer than rest of club, straight and 

sharply bent at base Nascus 

Apiculus otherwise 3 

3. Primaries with a tubular, or at least well marked, recurrent 

vein in cell 4 

Recurrent vein scarcely traceable or absent 9 

4. Antennae with a distinct, slender, reflexed apiculus 5 

Antennal club fusiform, more or less elongate; arcuate or 
with a well rounded bend at middle 7 

5. Secondaries tailed Goniwrus 

Secondaries not tailed 6 

6. Apiculus sharply bent; primaries apically produced 

Protddes 

Apiculus recurved ; apex of primaries modera,te..E par gy reus 

7. Recurrent vein nearer vein 4 than vein 3 .8 

Recurrent vein nearer 3 Chimdes 



18 IOWA STUDIES IN NATURAL HISTORY 

8. Outer margin of secondaries slightly crenulate. .Codatractus 
Outer margin even Telegonus 

9. Club of antennae large, fusiform Plestia 

Club more slender, with a distinct apiculus 10 

10. Apiculus much shorter than rest of club, bent at about a 

right angle 11 

Apiculus about as long as rest of club, usually sharply re- 
flexed or recurved 13 

11. Secondaries lobed Polygonus 

Secondaries broadly rounded or merely produced at anal 
angle 12 

12. $ with a tuft of scales on upper surface of hind wings; 

palpi moderate Cogia 

No tuft. Palpi exceeding front by about length of head 
Phoed&nus 

13. Vein la of secondaries about two-thirds as long as lb. Pri- 
maries with a broad yellow band Cecropterus 

Vein la longer. Primaries with spots or a broken yellow 
band 14 

14. Outer margin of secondaries broadly rounded; of primaries 

slightly and almost evenly convex Thorybes 

Outer margin of secondaries more or less produced and 

angled at lb; of primaries slightly sinuate Achalarus 

Outer margin of secondaries with a slight truncate lobe 
between veins 3 and 4 Cabares 

Genus PHOCIDES Hiibner 
Phooides Hbn., Verz. bek. Schmett. 103, 1820. Type PapiUo 

palemon Cr. 
Erycides Hbn., Verz. bek. Schmett. 110, 1820. Type Papttio 

pygmoHion Cr. 
Dy senius Scudder, Syst. Rev. 46 (67), 1872. Type Erycides 

albicilla H. S. 
Palpi oblique, vestiture smooth, deep and scaly; third joint 
small. Antennae with club rather long, moderately thick; api- 
culus not more than one-half as long as rest of club, very slender 
and abruptly bent. Primaries shaped as in Goniurus, with a 




HESPERIOIDEA OF AMERICA 19 

costal fold in the male. Cell over two-thirds as 
long as wing. Vein 5 nearer to 6 than to 4 ; L. 
D. C. long and strongly curved. Vein 3 near 
end of cell and 2 well toward base of wing. Re- 
current vein faint, at base of vein 4. Secondaries 
produced toward anal angle with outer margin 
sharply bent at lb but not lobed. Outer margin 
only slightly irregular. Phocides is easily rec- 
ognized by the general habitus of the species 
when once seen. Fig. 2. 

The action of former writers in combining 
these three genera was undoubtedly correct, 
though some slight differences of structure exist 
between the species occurring in our country. Fig 2 Ph0C ^Tb a . 

tabano Lucas. 
Key to the Species Neuration 

Primaries immaculate, black batabano 

Primaries with a red spot above lUea 

Primaries with hyaline white spots urania 

1. PHOCIDES BATABANO 

Eudamus batabano Lucas, Sagra, Hist. Cuba, vn, 624, 1857. 
Erycides mancinus H.-S., Corr.-Blatt Eegensb. xvi, 143, 1862. 
Erycides cikeechobee Worthington, Papilio i, 133, 1881. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 199, pi. x, 1911. 
Florida, March and April. 

2. PHOCIDES LILEA 

Erycides lilea Eeakirt, Proc. Acad. Nat. Sci. Phil. 1866, 339. 
Erycides albicilla H. S., Corr-Blatt Eegensb. xxm, 169, 1869. 
Erycides socius Butl. & Druce, Cist. Ent. I, 112, 1872. 
Bysenius cruentus Seud., Syst. Rev. 46(67), 1872. 
Erycides sangumea Scud., Syst. Rev. 47(68), 1872. 
Erycides decolor Mab., Bull. Soc. Ent. France 1880, xlvi. 
Biol. Cent.-Am., Rhop. n, 296, pi. 76, ft. 23, 24, 1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 199, 1911. 

The only specimen which I have seen bears the label ' ' Colima, 
Mex. ' 9 Skinner lists a Texas record by Capt. Pope in the Mex- 
ican Boundary Survey. 

3. PHOCIDES URANIA 

Erycides urania Westw. & Hew., Gen. Diurn. Lep. 510, pi. 79, f. 1, 1852. 
Erycides texana Scud., Syst. Rev. 47(68), 1872. 




20 IOWA STUDIES IN NATURAL HISTORY 

Skinner, Ent. News i, 23, 1890, and II, 101, pi. 1, 1891. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 198, 1911. 
Texas, Arizona and southward. 

Genus NASCUS Watson 

Naseus Watson, Proe. Zool. Soc. London, 1893, 28, Type Pa- 
pilio phocus Cr. 
Watson characterized this genus as follows: "Antennae: 
club rather robust, bent into a hook, terminal portion very 

slender and rather longer than rest 
"Y of club. Palpi upturned, third joint 
3 \ / J almost concealed. Fore wing: outer 

margin very much longer than inner 
margin, the apex being very conspicu- 
ously produced; cell more than two- 
thirds the length of eosta; male with 
cl^^t^t^ntToumZ' oi ^ costal fold; discocellulars very 
primary oblique, the lower one slightly the 

longer ; vein 3 shortly before end of cell ; vein 2 close to base of 
wing. Hind wing anally produced, and with an inconspicuous 
tooth at vein lb ; vein 7 close to end of cell ; discocellulars and 
vein 5 barely traceable ; vein 3 immediately before the end of the 
cell; vein 2 considerably nearer to end of cell than to base of 
wing. Hind tibiae with a long fringe of coarse hairs and with 
two pairs of spurs. ' ' In our fauna the very long apiculus sepa- 
rates this genus from all others. Fig. 3. 

1. NASCUS HESUS 

Telegorms hesus Westw. & Hew., Gen. Diurn. Lep. n, pi. 78, f. 5, 1852. 
? Papilio nidas Fab., Mant. Ins. n, 86, 1787. 
? Eudamus etias Hew., Desc. Hesp. 13, 1867. 
Aaron, Ent. News I, 25, 1890 and n, 101, pi. 1, 1891. 

Eudamus euribates Skinner (not Cramer) Trans. Am. Ent. Soc. xxxvii, 
191, pi. x, 1911. 
Mexico to Brazil; Skinner includes Texas, following Aaron, presumably. 

I have compared Cramer's, Westwood and Hewitson's and 
Skinner's figures, and find that the two latter agree very well, 
but that, even allowing for the poor quality of Cramer's figure, 
they can hardly be euribates Cramer. I have no data on the 
occurrence of the species in this country. 




HESPERIOIDEA OF AMERICA 21 

Genus POLYGONUS Hiibner 
Polygonus Hbn., Samml. exot. Schmett. n, t. 144, 1822-6. Type 

Polygonus lividus Hbn. 
Acolastus Scud., Syst. Rev. 50, 1872. Type Hesperia savigny 

Latr. 
Nennius Kirby, "Wytsman's Hiibner 105, 1902. New name for 

Polygonus and Acolastus. 
Second joint of palpi appressed, densely sealed ; third porrect, 
small. Reflexed apiculus abruptly constricted, about one-half 
as long as rest of club. Head slightly 
wider than thorax. Primaries narrow, 
costa evenly curved, inner margin nearly 
straight and outer sharply curved oppo- 
site cell; no fold in male. Cell three- 
quarters as long as Wing; Vein 5 about Fig. 4. T^gonus arnyntas 

equidistant between 4 and 6; spur vein F %eura°tfon of $££• b * 
scarcely traceable, nearer to 3. Second- 
aries broadly rounded, lobed at anal angle. Fig. 4. 

According to Scudder (Hist. Sk. 253) Polygonus was pre- 
occupied by Polygona in the Mollusca. Acolastus was preoccu- 
pied in the Coleoptera, a fact which was overlooked for many 
years, and Kirby offered Nennius to replace it. According to 
the current international rules of zoological nomenclature a dif- 
ference of one letter is sufficient to validate a generic name, so 
Polygonus cannot be regarded as preoccupied, and therefore 
must be retained for arnyntas. 

1. POLYGONUS AMYNTAS 

Papilio arnyntas Fab., Syst. Ent. 533, 1775. 

Polygonus lividus Hbn., Samml. exot. Schmett. n, t. 144, 1822-26. 

Hesperia savigny, Latr., Ene. Meth. ix, 741, 1823. 

Skinner, Trans. Am. Ent. Soc. xxxvn, 200, pi. x, 1911. 

The typical form is very dark. It occurs in Florida in Aug. and Sept. 

la. race ARIZONENSIS 

Erycides arnyntas arizonensis Skinner, Trans. Am. Ent. Soc. xxxvn, 209, 
pi. x, 1911. 

The western race of arnyntas is paler than the typical form, 
both above and below, and the pale transverse bands of the sec- 
ondaries are faintly visible on the upper surface. Texas and 
Arizona, September. 



22 IOWA STUDIES IN NATURAL HISTORY 

Genus PROTEIDES Hiibner 
Proteides Hbn., Verz. bek. Schmett. 104, 1820. Type Papilio 

idas Cr. 
Dicranaspes Mab., Ann. Soc. Ent. Relg. xxi, 24, 1878. Type 

Papilio idas Cramer. 
Proteides is very close to Epargyreus, and I think that with a 
large series of the tropical species the two genera will be found 
to be scarcely worthy of separation. In our fauna, however, the 
sharply constricted and reflexed apiculus and the narrow, apio 
ally produced primaries of Proteides are very distinctive. The 
male has no costal fold. Fig. 5. 

1. PROTEIDES IDAS 

Papilio idas Cramer, Pap. Exot. in, 118, p. ccux, A, B, 1779-80. 
Papilio mercurius Fab., Mant. Ins. ii, 86, 1787. 
Biol. Cent. -Am., Bhop. n, 301, pi. 77, f. 5, gen., 1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 194, 1911. 

Occurs in Texas, New Mexico and Arizona. I have no further data. 

Genus EPARGYREUS Hiibner 

Epargyreus Hiibner, Verz. bek. Schmett. 105, 1820. Type Pa- 
pilio tityrus Fab. 
Second joint of palpi closely appressed, densely clothed with 

scales in which the small third joint is almost concealed. An- 
tennae about one-half as long as the 
primaries, club more or less sharply 
curved at the middle. Head not quite 
as wide as thorax. Primaries elong- 
ate, rather narrow; outer and inner 
margins about equal in length, outer 
slightly more oblique but otherwise 
similar to Goniurus. Costal fold pres- 
ent. Cell three-quarters as long as 
wing ; vein 5 slightly nearer to 4 than 
to 6. Recurrent vein nearer to vein 
3. Vein 1 strongly sinuate. Seeon- 

Fig. 5. a. Club of antenna of e. daries rounded, lobed at anal angle. 

zestos Greyer, b. Club of antenna TT\\ cr K 
of P. idas Cramer, c. Neuration % *&• «*• 

of E. tityma Fab. The primaries are longer and n&r . 

rower in exadeus than in zestos and tityrus, and the apiculus of 




HESPERIOIDEA OF AMERICA 23 

the antennae shows a tendency to be more slender and more 
sharply bent. This has led me to the conclusion stated under 
Proteides that the two genera are possibly not distinct. 

Key to the species 

1. Under surface of secondaries with a silky white patch 2 

No silky white on secondaires zestos 

2. Spots of primaries deep yellow and usually broadly contiguous. tityrus 
Spots small and widely separated, or if larger, very pale yellow, exadeus 

1. EPABGYBEUS ZESTOS 

Proteides zestos Geyer, Zutr. exot. Sehmett. IV, 9, t. 106, ff. 615, 616, 1832. 
Eudamus oberon Worthington, Papilio I, 132, 1881. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 193, 1911. 
Florida, August and September. 

2. EPABGYEEUS T1TYBVS 

Papilio tityrus Fab., Syst. Ent. 532, 1775. 

Papilio clarus Cramer, Pap. Exot. i, 66, pi. xli, E, F, 1775. 

Holland, Butterfly Book 323, pi. xliti, f. 5, 1898. 

Smyth, Ent. News XIX, 191, pi. X, 1908. 

Skinner, Trans. Am. Ent. Soc. xxxvn, 192, 1911. 

Ranges throughout the United States and into southern Can- 
ada and South America. June to August. 

ab. OBLITEBATTJS 

Epargyreus tityrus obliteratus Seudder, Butt. New Eng. n, 1402, 1889. 

Only three small, rounded spots in place of the diseal band, and only one 
small preapical spot. Silver on under surface of secondaries more exten- 
sive than usual. 

3. EPABGYBEUS EXADEUS 

Papilio exadeus Cramer, Pap. Exot. in, 118, pi. cclx, C, 1779-80. 
Biol. Cent.-Am., Rhop. II, 299, pi. 77, f. 1, gen., 1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 194, pi. x, 1911. 
Southern California, Arizona, New Mexico, March. 

Genus GONIURUS Hiibner 
Gordurus Hiibner, Verz. bek. Sehmett. 104, 1820. Type Papilio 

simplioius StoU. 
Eudamus Swainson, Zool. 111. (2), n, 48, 1831-2. Type Papilio 

proteus Linn. 
% Polythrix Watson, Proc. Zool. Soc. London, 1893, 19. Type 

Eudamus metallescens Mabille. 



24 



IOWA STUDIES IN NATURAL HISTOEY 




Second joint of palpi closely appressed, third porrect, small. 
Antennae a little over one-half as long as primaries, club slender, 
apiculus shorter and distinctly more slender than remainder. 
Primaries broad and short; outer margin evenly rounded to 

slightly sinuate, about as long as 

# f ^| jrf^ZK * nner ; costa evenly rounded, rela- 

Jr i /yjrJi ti ve ly short, without fold in one 
* h £ /W^r^i s P ec i es - Cell two-thirds as long as 
wing; vein 5 slightly nearer to 4 
than to 6. Secondaries with anal 
c angle produced into a long tail; 
outer margin slightly excavated op- 
posite cell and before tail, some- 
times slightly crenulate. Fig. 6. 

The above description is taken 
from simplicius and eurycles. Pro- 
teus has a longer cell as shown in 
the figure and both proteus and 
F ]f\ 6 - ^rf'T^A Mp™ 5 ° f **»*; dorantes have relatively shorter 

plicius Stoll. b. Club of antennae of ^ 

simpiicms stoii. c. Negation of pro- antennae. It may prove desirable 

teus Linn r 

to use Eudamus for these two 
species, but without knowing more of the related Central Amer- 
ican fauna I cannot make a satisfactory decision on this point. 
Of the other three North American species which I here remove 
from Gomurus I feel that albofasciatus and zilpa warrant the 
establishment of a new genus, and that the relationship of alceus 
to melon, in spite of its tailed secondaries, is too close to be dis- 
regarded. 

Key to the speeies 

1. Upper surface with shining green hairs proteus 

Without green hairs 2 

2. Fringes checkered; spots not united to form a straight band, .dorantes 
Fringes not checkered; band usually present 3 

3. Band always present; no costal fold in male; outer margin of primar- 
ies slightly sinuate eurycles 

Band sometimes broken or even absent; male with fold; outer margin 
slightly convex simplicius 

1. GONIURUS PROTEUS 

Papilio proteus Linn., Syst. Nat. I, 484, 1758. 

Scudder, Butt . New Eng., n, 1386, 1889. 

Biol. Cent. -Am., Bhop. n, 277, pi. 75, f. 5, gen., 1893. 



HESPERIOIDEA OF AMERICA 25 

Holland, Butterfly Book 321, pi. xlv, f. 6, 1898. 
Skinner, Trans. Am. Ent. Soe. xxxvn, 194, 1911. 

Florida and Georgia, August to October. Arizona and Texas, 
June and July. Dr. Skinner gives the range as New York to 
the Gulf and southward through Mexico and Central America. 

2. GONIURUS DORANTES 

Papilio dorantes Stoll, Pap. Exot., Supp., 172, pi. xxxix, f. 9, 1790. 
Eudamus amisus Hew., Desc. Hesp. 5, 1867. 
Eudamus protillus H.-S., Corr.-Blatt Regensb. xxm, 171, 1869. 
Biol. Cent.-Am., Rhop. n, 278, pi. 75, f. 7, $ gen., 1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 197, 1911. 
Southern California, Mexico. 

2a. race BAUTEBBEBGI 
Evdamus protillus var. rauterbergi Skinner, Ent. News VI, 113, 1895. 
Skinner, Trans. Am. Ent. Soe. xxxvn, 197, 1911. 

Skinner says that this form is ' ' smaller and very much darker 
than protittus; the fringes are far less marked, and the tails 
lack the admixture of light hairs. ' ' 

Texas, Arizona and southward ; July and September. 

3. GONIURUS SIMPLICIUS 

Papilio simplidus Stoll, Pap. Exot., Supp., 171, pi. xxxix, f. 6, 1790. 
Biol. Cent. -Am. Rhop. n, 270, pi. 75, f. 1, $ gen., 1893. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 196, 1911. 

Some females can scarcely be told from ewrycles, but usually 
the obsolescence of the hyaline marks of the primaries and the 
slightly different shape of the wings enable one to recognize 
the species. The males are readily identified by the costal fold. 

Texas, March and October. 

4. GONIURUS EURYCLES 

Besperia ewrycles Latr., Ene. Meth. ix, 730, 1823. 

Skinner, Ent. News xn, 171, 1901. 

Skinner, Trans. Am. Ent. Soc. xxxvn, 197, pi. x, 1911. 

I have eurycles from Guatemala, taken in April, and from 
Colombia taken in November, but aside from Dr. Skinner's note 
in the Entomological News I have seen no records of its occur- 
rence north of Mexico. 

Genus CHIOIDES gen. nov. 
Palpi large, porrect ; second joint deeply scaled, third strong, 



26 IOWA STUDIES IN NATURAL HISTORY 

conspicuous. Antennae less than one-half as long as primaries, 
club relatively smaller and thicker than in Goniwrus, and more 
broadly curved, with the apiculus less distinct. Primaries with 
the apex subtruncate, outer margin concave below apex. Cell 
about three-fourths as long as wing; recurrent vein nearer to 
vein 3 than to vein 4 ; bases of 3 and 4 much farther apart than 
M. D. C. and L. D. C. combined. Costal fold present in our 
species. Fig. 7. 

Type: Eudamus albofasciatus Hewitson. 

Catillus, a Central American species, and albofasciatus are 
very closely related, and agree in the form of the male genitalia. 
Zilpa differs somewhat in the form of the wings and the male 
genitalia, but on the whole it is apparently related to the other 
species, and with them distinct from Goniurus. The difference 
is scarcely greater than between proteus and simplicius. 

1. CHIOIDES ALBOFASCIATUS 

Eudamus albofasciatus Hew., Besc. Hesp. 3, 1867. 

Biol. Cent.-Am., Ehop. n, 280, pi. 75, f. 11, $ gen., 1893. 

Skinner, Trans. Am. Ent. Soc. xxxvn, 197, 1911. 

Texas, March. Arizona, July and September. Distinguished from zilpa 
by the long narrow white band on the under surface of the secondaries. 

2. CHIOIDES ZILPA (Plate I, Fig. 5) 
Goniurus zilpa Butler, Lep. Exot. 109, t. XL, f. 2, 1872. 
Biol. Cent. -Am., Ehop. n, 279, pi. 75, f 8, $ gen., 1893. 
Patagonia Mts., Arizona, May. Kerrville, Tex., September. 

Genus CODATRACTUS nom. nov. 
Heteropia Mabille, Le Nat. 1889, 68. Type Heteropia imitatrix 

Mab. Preoccupied in sponges by 
Heteropia Carter, Ann. &Mag. Nat. 
Hist. (5), xvm, 47, 1886. 
Structure in general similar to 
Chioides but with veins 3 and 4 of the 
primaries not so far apart at their 
bases as the combined length of the 
two discocellulars and the recurrent 
vein nearer to 4 than to 3. The an- 
Detaii 7 of^n^atlon^end *¥ 5S of tennal club is fusiform, more or less 
¥t^driG$^JS^&Z: sharply bent near the middle but with 
of ^imL£ T T S™'oi n L£nnf. the distal portion not differentiated. 







HESPERIOIDEA OP AMERICA 27 

Outer margin of primaries slightly sinuate ; no costal fold in male 
of melon; I have not seen a male of alcaeus. Fig. 7. 

To place such a strongly tailed species as alcaeus with a species 
in which the secondaries are merely angled is radical, but a study 
of related Central American species ha$ led me to believe that 
in this case, at least, it is justified. Alcaeus agrees with melon 
very closely in structure, and the male genitalia of the two 
species are very similar. 

1. CODATRACTUS ALCAEUS 

Eudamus alcaeus Hew., Desc Hesp. 3, 1867. 
Skinner, Ent. News xn, 171, 1901. 

My only specimen is a female from Mexico, and I have seen 
no others. The reference to the Entomological News is the only 
trecord of its occurrence in the United States with which I am 
familiar. 

2. CODATRACTUS MELON 

Heteropia melon Godman & Salvin, Biol. Cent.-Am., Rhop. n, 297, pi. lxxvi, 
g. 26, 27, 1893. 
The typical form of melon is not known to occur north of Mexico. 

2a. race AEIZONENSIS 
Heteropia melon var. arizonensis Skinner, Ent. News xvi, 232, 1905. 
Skinner, Trans. Am. Ent. Soc. xxxvii, 186, pi. x, 1911. 

Baboquivari Mts., Ariz., July. 

Differs from true melon in the whiter marginal area of the secondaries 
below. 

Genus TELEGONUS Hiibner 
Telegonus Hiibner, Verz. bek. Schmett. 104, 1820, Type Papilio 
anaphus Cramer. 
Palpi oblique, third joint distinct. Antennae with a long 
slender tapering club, not sharply bent but curved at the middle. 
Primaries broad, outer margin equal to inner; costa slightly 
curved, without a fold in the male; outer margin very slightly 
sinuate. Secondaries produced and angled at lb ; outer margin 
straight from vein 7 to the anal angle. Cell of primaries about 
two-thirds as long as wing, discocellulars very oblique ; vein 5 
slightly nearer to vein 4 than to vein 6 ; recurrent vein near 4 ; 
vein 2 over one-half as far from base of wing as from 3. 



28 IOWA STUDIES IN NATURAL HISTORY 

1. TELE60NUS HAHNELI 

Aethilla hahneli Staud., Exot. Tagf. I, 291, n, pi. 98, 1888. 
Biol. Cent.-Am., Rhop. n, 306, pi. 77, ff. 13, 14, 1893. 
Skinner, Ent. News xn, 171, 1901. 

Staudinger's figure does not agree at all with that of Godman 
and Salvin, which represents the species recorded from North 
America. Since the latter authors state, however, that they had 
specimens from Dr. Staudinger himself, the best thing that we 
can do is retain the name in its present usage until the types 
can be examined. 

Arizona ( Skinner) . 

I have a specimen from Dr. Skinner labelled "Jamaica," Be- 
yond his record in the Entomological News I have no knowledge 
of the occurrence of the species within our country. 

Genus PLESTIA Mabille 
Plestia Mab., Le Nat, (2), n, 146, 1888. Type Plestia staudin- 
geri Mob. 

Palpi porrect, exceeding front by 
length of head; second joint with 
shaggy vestiture of scales and hair, 
third conical, moderately large. An- 
tennae with the club fusiform and 
pointed, almost as long as the shaft. 
Primaries trigonate, outer margin 
bent opposite cell ; costal fold present 
Fi?r. s. piestia dorus Edw. a. in male. Cell over two-thirds as long 
ciub of antennae. Nation as wing , reC urrent vein absent. Vein 5 
nearer 6 than 4. Secondaries trigonate, prominently lobed at 
anal angle. Legs and under surface of thorax very hairy. 

Fig. 8. 

1. PLESTIA DORUS 

Eudamus dorus Edwards, Papilio n, 140, 1882. 
Biol. Cent.-Am., Bhop. n, 290, pi. 76, ff. 8, 9, 1893. 
Holland, Butterfly Book, 322, pi. xlv, f. 11, 1898. 
Skinner, Trans. Am. Ent. Soe. xxxvn, 187, 1911. 
Arizona, May, June and July. New Mexico, May. 

Genus AOHALARUS Seudder 
Aohalarus Seudder, Syst. Rev. 50 (71), 1872. Type Papilio 
lycidas, Abbot and Smith. 




HESPEKIOIDEA OF AMERICA 29 

Murgaria Watson, Proc. Zool. Soe. London, 1893, 37. Type 
Telegonns albocitiatiis Mabille. 

Palpi porrect; second joint closely and roughly scaled; third 
small, almost concealed in vestiture of second. Antennae about 
one-half as long as primaries; club slender, tapering gradually 
into the reflexed tip, which is not quite as long as the rest of the 
club. Primaries moderately broad ; costa slightly rounded, with 
or without the fold in the male ; outer margin slightly sinuate in 
the male, more evenly rounded in the female ; cell slightly over 
two-thirds as long as wing; spur vein very faintly indicated, 
near vein 4 ; 5 slightly nearer to 4. Secondaries angled at lb in 
the male, more rounded in the female. In epigona this char- 
acter is very variable, some specimens having the angle acute 
and others obtuse. Vein 5 is not present, as stated by Watson 
(P. Z. S. 1893, 34) but is indicated by a slight fold. 

Although it seems very radical to combine these genera, a 
careful consideration of their structures has failed to disclose any 
basis for their separation. Epigona, formerly placed in Phov- 
dinus, is obviously congeneric with albociliaius, and hence un- 
der the old arrangement would fall into Murgaria, while both 
dffer from lycidas only in the absence of the costal fold in the 
males. Some specimens of the white fringed species have the 
anal angles of the secondaries much more acute than in lycidas, 
and therefore look much different, but as I have stated, this 
character is very variable. The male genitalia are similar and 
of a peculiar form. 

Key to the species 

1. Primaries with yellow spots lycidas 

Primaries with or without white spots 2 

2. Primaries with well defined whitish hyaline spots epigona 

Primaries with an obscure dark band, rarely with a few white spots 
• albociliatus 

1. ACHALABVS LYCIDAS 

Papilio lycidas Abbot and Smith, Lep. Ins. Ga. I, 39, pi. 20, 1797. 
Proteides lyciades Geyer, Zutr. ex. Schmett. rv, 10, ff. 621, 622, 1832. 
Skinner, Trans. Am. Ent. Soc. xxxvii, 188, 1911. 

New York and Pennsylvania, August, and south to the gulf, where it 
is taken in May and June. 



30 IOWA STUDIES IN NATURAL HISTORY 

2. ACHALARUS EPIGONA 

Myscelus epigona H.-S., Corr.-Blatt Kegensb. xxin, 167, 1869. 
Eudamus epigena Butler, Trans. Ent. Soc. Lond., 1870, 493. 
Eudamus orestes Edw., (Lintner Ms.), Cat. Diurn. Lep. N. A. 58, 1877. 
Biol. Cent. Am., Rhop. n, 332, pi. 80, ff. 9-11, 1893. 
Arizona, June and August. 

3. ACHALARUS ALBOCILIATUS 

Telegonus albociliatus Mab., Pet. Nouv. Ent. n, 162, 1877. 
Eudamus coyote Skinner, Can. Ent. xxiv, 164, 1892. 

Texas and Arizona. We have been confusing two species under this 
name, but at present I am unable to correct the error with certainty. 

Genus CECROPTERUS Herrich-Sehaffer 
Cecrops Him., Zutr. Exot. Schmett. t. 32, ff. 183, 184, 1818. Type 

Cecrops zarex Hbn. Preoccupied in Crustacea. 
Cecropterus H.-S., Corr.-Blatt Regensb. xxm, 131, 1869. For 

Cecrops Hbn. 
Rhubdmdes Scud., Butt. New Eng. m, p. 1854, 1889. Type 
Eudamus cellus Boisd. & Lee. 

Palpi larger than in Achalarus; second joint 
oblique, roughly scaled; third porrect, moderate, 
not concealed by vestiture of second. Antennae 
about one-half as long as primaries; club slender, 
tapering, bent near middle, with the apiculus 
scarcely more slender than the basal portion. Pri- 
maries similar to Achalarus $ and Thorybes; cell 
slightly over two-thirds as long as wing ; recurrent 
vein faint but indicated at base of vein 4 ; 5 slight- 
Fig. 9. Cecrop- ly nearer to 4 than to 6 ; discoeellulars less oblique 
Bd. and Lee. than in Achalarus, more as inThorybes; costal fold 
tenna? b. De- aot present in male. Outer margin of secondaries 
tion ; anai area rounded, apex broadly rounded ; Vein la about two- 

of secondary . . . . .,, -r,- ^ 

thirds as long as lb. Fig. 9. 
Cellus resembles Thorybes very closely in most of its struc- 
tures, but I hardly think that the species belongs there. I do not 
see anything to separate it from the genus Cecropterus, however, 
and so am placing it for the present with the other species whose 
banded primaries give them a close superficial resemblance. 
Pseudocellus appears to be closer to Achalarus but I have not 
had material for dissection and so prefer to leave it with cellus. 




HESPEEIOIDEA OF AMERICA 



31 



1. CECROPTERUS CELLUS 

Eudamus cellus Bd. & Lee., Lep. Am. Sept. t. 73, 1833. 
Cecrops festus Geyer, Zutr. exot. Schmett. V, 21, ff. 907, 908, 1837 
Biol. Cent.-Am., Ehop. II, 331, pi. 80, f. 8, $ gen., 1894. 
Holland, Butterfly Book 326, pi. xlv, f. 12, 1898. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 189, 1911. 

Pennsylvania, July. Virginia and West Virginia, May and June. Texas 
and Arizona, April and August. 

2. CECROPTERUS PSEUDOCELLUS 

Aohalarus pseudocellus Coolidge and Clemence, Ent. News xxn, 3, 1911. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 190, 1911. 

Arizona, June to September inclusive. This species is smaller 
and darker than cellus, lacks the terminal pale area on the under 
surface of the secondaries and has a pale ring at the base of the 
antennal club. I have examined a long series in the Barnes 
collection without finding any specimen in which the pale ring 
could not be seen. 

Genus THORYBES Scudder 
Tkorybes Scud., Syst. Rev. 50 (71), 1872. Type PapUio lathyl- 

lus A. & S. 
Lintneria Butler, Trans. Ent. Soc. 

PapUio daunus Cramer. 
Coccdus G. & S., Biol. Cent-Am., Rhop. n, 336, 1900 

Eudamus pylades Scud. 
Palpi with the second joint appressed, 
densely scaled ; third small, porrect, partly 
concealed by scales of second. Club of an- 
tennae moderate, tapering into a slender 
apiculus which is slightly shorter than the 
rest of the club. In specimens the apiculus 
varies from sharply reflexed to slightly re- 
curved. Primaries rather short and broad 
with the costa and outer margin convex; 
cell slightly over two-thirds as long as 
wing; recurrent vein barely indicated near 
vein 4; 5 equidistant between 4 and 6; 2 Fig. 10. a. ciub of an- 
nearer base of wing than to 3. Secondar- $X a £ Fe^tioT^ 
ies broadly rounded, length along vein 6 f ^tt^i^on^: 
about equal to or greater than along lb; SoSSJS ^Xfi 



London, 1877, 57. Type 
Type 




32 IOWA STUDIES IN NATURAL HISTORY 

anal angle sometimes very slightly prominent. Costal fold pres- 
ent in pylades and drusius but not in the other species. Fig. 10. 
In establishing Cocceius Godman and Salvin state that it dif- 
fers from Thorybes in the presence of the costal fold and that 
this indicates that its relationship is rather with Achalarus. It 
is related in many more points, however, to Thorybes, and the 
costal fold does not seem adequate to separate the two groups as 
genera. The male gentalia of the species are similar. 

Key to the species 

1. Fringes of secondaries white, at least in middle of outer margin. drusius 
Fringes not white 2 

2. Under surface of secondaries transversely strigate 3 

Under surface not strigate 4 

3. Hyaline spots moderate to small, without dark outlines; ground color 

dark mexicanus 

Hyaline spots large with dark outlines; ground color pale 

mexicanus, race nevada 

4. Spots usually large, extending from vein to vein; palpi usually pale 

below bathyllus 

Spots usually small ; palpi usually concolorous with body below . . pylades 
Spots absent pylades, ab. immaculata 

1. THORYBES DRUSIUS 

Eudamus drusius Edw., Can. Ent. xv, 211, 1883. 

Biol. Cent.-Am., Rhop. n, 336, 1894. 

Skinner, Trans. Am. Ent. Soc. xxxvii, 185, pi. x, 1911. 

Arizona, June, July and August. Western Nebraska, Leussler. 

2. FHORYBES PYLADES 

Eudamus bathyllus Harris (not A. & S.), Ins. Inj. Veg. 3rd ed., 312, 1862. 
Eudamus pylades Scud., Proc. Bost. Soc. Nat. Hist, xm, 207, 1870. 
Biol. Cent.-Am., Rhop. n, 336, pi. 80, f. 23, 1894. 
Holland, Butterfly Book 324, pi. xlviii, f. 6, 1898. 
Skinner, Trans. Am. Ent. Soc. xxxvii, 176, 1911. 

Occurs throughout the United States and most of Canada. In Florida 
and Texas it has been taken as early as April and as late as October; far- 
ther north it flies from May to August. 

ab. IMMACULATA 

Eudamus pylades immaculata Skinner, Trans. Am. Ent. Soc. xxxvii, 177, 
1911. 
This is a rather uncommon form in which the hyaline spots of the pri- 
maries are entirely absent. 



HESPERIOIDEA OF AMERICA 33 

3. THORYBES DAUNUS 

Papilio daunus Cramer, Pap. Exot. n, 44, pi. c&xvi, F, 1777. 
Papilio bathtyllus Abbot & Smith, Lep. Ins. Ga. I, 43, pi. xxii, 1797. 
Holland, Butterfly Book 325, pi. xlviii, f . 5, 1898. 
Skinner, Trans. Am. Ent. Soe. xxxvn, 178, 1911. 

Some females of pylades and bathyllvx are difficult to sepa- 
rate but as a rule the size of the spots and color of the palpi in 
this species are characteristic. The males of this and the fol- 
lowing species are easily separated from the others by the absence 
of the costal fold. 

Florida north and west to Pennsylvania, Iowa, Nebraska and 
Texas. I have seen southern specimens dated May and August, 
while farther north the species occurs from June to September. 

4. THORYBES MEXICAN A 

Eudamus mexicana H.-S., Corr.-Blatt Regensb. xxm, 198, 1869. 
Eudamus ananvus Plotz, Stett. ent. Zeit. xliii, 99, 1882. 
Biologia Cent.-Am., Rhop. n, 334, pi. 80, ff. 15, 16, 17, 1894. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 180, 1911. 

Specimens in the Barnes collection which agree with those in the British 
museum are similar to pylades above but faintly strigate below, and rather 
darker than normal specimens of pylades. 

Arizona, June and July. Colorado, July. 

4a. race NEVADA 
Thorybes nevada Scud., Syst. Rev. 50 (71), 1872. 
Eudamus aemilea Skinner, Ent. News iv, 64, 1893. 
Holland, Butterfly Book 325, pi. xlvi, f. 39, 1898 (type). 
Wright, Butt. W. Coast 254, pi. xxxn, f. 478, 1905. 
Skinner, Trans. Am. Ent. Soc. xxxvn, 182, 1911. 

Ground color rather pale, with( a fine terminal line and margins of spots 
darker. Spots large. Strigation of under surface usually heavy. 

California and Oregon, June and July. 8000 ft. 

Genus CABARES Godman & Salvin 
Cabares G. & S., Biol. Cent-Am., Rhop. n, 337, 1894. Type 
Thanaos potrillo Lucas. 
"Antennae with a gradually tapering club, curved in the 
middle into a crook. Palpi porrect, the third joint rather 
prominent. Primaries with the cell more than two-thirds the 
length of the costa, the second, third, and fourth subcostal seg- 
ments subequal; lower discocellular rather shorter than the 
middle, the two forming an oblique line at a large acute angle to 



34 IOWA STUDIES IN NATURAL HISTORY 

the axis of the wing; third median segment less than h<alf the 
second, and rather shorter than the first; a curved recurrent 
nervule starts from the end of the cell. Secondaries with the 
discocellulars very slender; third median segment very short; 
second subcostal segment also short. Primaries short, slight- 
ly truncate at the tip; no costal fold in the male; second- 
aries with a projection in the middle of the outer margin from 
the end of the median nervure. Hind tibiae with two pairs of 
spurs." 

"Type Thanaos potrMo Lucas." (Original description). 

This appears to be a good genus, and the one species which 
occurs in our fauna can easily be placed by the peculiar lobe on 
the outer margin of the secondaries. Fig. 10. 

1. CABABES POTRILLO 

Thanaos potrillo Lucas, Sagra's Hist. Cuba vn, 641, 1857. 
Biol. Cent.-Am., Bhop. II, 337, pi. 80, ff. 24, 25, 26, 1894. 
The species is occasionally taken in Texas. 

Genus COGIA Butler 
Cogia Butler, Trans. Ent. Soc. London 1870, 508. Type Cogia 
hassan Butler. 
Palpi porrect; second joint heavily clothed with scales; third 
small but not concealed. Antennae about one-half as long as 
primaries; club moderately thick, tapering into the short, re- 
flexed apiculus. This is about half as long as the rest of the 
club and is usually bent at about a right angle. Shape of wings 
similar to Thorybes but costa of primaries less strongly curved 
and secondaries a little more produced anally. Cell of primaries 
about two-thirds as long as wing; vein 5 intermediate between 
4 and 6 ; recurrent vein faintly indicated, nearer to 4 than to 3. 
Primaries of male without costal fold but secondaries with a 
short tuft of .scales lying in the fold along vein lb near the base 
of the wing. Fig. 10. 

Key to the species 

1. Fringes fuscous 2 

Fringes white hippdlus 

2. Subapical spots indistinct; those between veins 2 and 4 usually lack- 
ing ; color dark cdlchas 

Subapical spots clear; those between 2 and 4 usually present; color 
pale fuscous outis 



HESPEEIOIDEA OF AMERICA 35 

1. COGIA CALCHAS 

Eudamus calchas H.-S., Corr.-Blatt Eegensb xxm, 188, 1869. 
Spathilepia terrariea Butler, Lep. Exot. Ill, t. XL,, f. 8, 1872. 
Biol. Cent.-Am., Rhop. II, 340, pi. 81, f. 6, $ gen., 1894. 

Texas, October. Most specimens can be distinguished from outis by the 
dark color and limited maculation. 

2. COGIA OUTIS 

Eudamus outis Skinner, Ent. News v, 332, 1894. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 184, pi. x, 1911. 

Texas, August. Ground color pale fuseous, as in ftippalus. The primaries 
usually have the two hyaline spots between veins 2 and 4 but I have seen 
specimens in which these were lacking or greatly reduced. 

3. COGIA HIPPALUS 

Eudamus hippalus Edw., Papilio n, 27, 1882. 
Hesperia gila Plotz, Stett. ent. Zeit. xlvii, 91, 1886. 
Biol. Cent.-Am., Bhop. II, 340, pi. 80, ff. 29-31, 1894. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 184, 1911. 

Southern Arizona and New Mexico, June, July and August. 

Genus PHOEDINUS Godman & Salvin 
Phoedirms G. & S., Biol. Cent-Am., Rhop. n, 335, 1894. Type 
Eudamus emeus H.-S. 

I was inclined for a time to unite this genus with Cogia, dis- 
regarding the tufted secondaries, but the large palpi with their 
conspicuous third joint serve to distinguish it so easily that it 
seems better to retain it. The spur vein is very faintly indicated 
near vein 4. There are no secondary sexual structures in the 
male. 

1. PHOEDINUS MYSIE 
Thorybes mysie Dyar, Jn. N. Y. Ent. Soe. xn, 40, 1904. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 181, 1911. 

This species is not represented in the Barnes or Streeker collections, and 
I have seen nothing which answers the description. Apparently it is a 
Phoedmus with fuscous fringes and more spots on the primaries than 
oaicus. It was described from the Patagonia Mts., Arizona. 

2. PHOEDINUS CAICUS 

Eudamus caicus H.-S., Corr.-Blatt Eegensb. xxm, 188, 1869. 
Eudamus schaefferi Plotz, Stett. ent. Zeit. xliii, 99, 1882. 
Eudamus moschus Edw., Papilio n, 141, 1882. 
Biol. Cent.-Am., Bhop. n, 335, pi. 80, ff. 18-20, 1894. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 183, 1911. 



36 IOWA STUDIES IN NATURAL HISTORY 

The fringes of the secondaries of this species are pure white, save at the 
apex and anal angle. 

Arizona, July and August. 

GROUP B 

The second group of the subfamily Hesperiinae is distin- 
guished from group A by the short cell of the primaries, the 
form of the antennal club, and the palpi. The cell Is never over 
two-thirds as long as the wing, and is usually a little less; th,e 
antennal club is ovate or fusiform, usually somewhat flattened 
and more or less curved, but never bent as in most of the genera 
of group A and never with a distinct apiculus; the palpi are 
porrect or oblique, either large or with hairy vestiture or both. 
The only similar palpi in group A are found in the genus Plestia. 

The genera of this group appear to be very poorly defined, 
owing to the structural variation of the species. If we split to 
the extent reached by some lepidopterists we can make a genus 
for practically every species, so the opposite course seems ad- 
visable, and I have therefore lumped a number of familiar genera 
to group species which appear to be related. This has resulted, 
especially in Pholisora, in the association of species which can 
easily be separated by structural differences, but in all cases 
these characters show a transition through the several species 
which causes me to regard them as unreliable for the separation 
of genera. 

Key to the genera 

1. Secondaries irregular, excavated opposite end of cell and 
before anal angle ; not trigonate. Yein 2 of primaries near- 
er base of cell than to vein 3 Systasea 

Not such insects 2 

2. Club of antennae long, slender, not distinctly flattened, and 

scarcely exceeding twice the diameter of the shaft 3 

Club thicker in at least one direction 4 

3. Primaries slightly excavated below apex; humeral angle 

prominent, rounded Eantis 

Apex rectangular; humeral angle normal Xenophanes 

4. Palpi large; third joint conspicuous; vestiture not roughly 

hairy Pholisora 

Palpi moderate to large ; third joint not conspicuous or ves- 
titure hairy 5 



HESPEBIOIDEA OF AMERICA 37 

5. Club of antennae elongate-ovate, flattened, blunt; species 

largely white or checkered Hesperia 

Club more or less fusiform and pointed . 6 

6. Outer margin of primaries evenly rounded or nearly so. . .7 
Apex of primaries subtruncate or rectangular. .8 

7. Vein 11 of primaries arising just beyond middle of cell and 

reaching costa before end of cell Chiomara 

Vein 11 arising at or beyond outer third of cell and ending 
in costa beyond end of cell Thanaos 

8. Anal angle of primaries broadly rounded; outer and inner 

margins about equal . Melanthes 

Anal angle sharply rounded ; outer margin distinctly shorter 
than inner 9 

9. Cell narrow, about equal to distance between cell and costa 

Grais 

Cell normal, much wider than this distance Timochares 

Genus HESPERIA Fabricius 

Hesperia Fab., Ent. Syst. m, (i), 258, 1793. Type Papilio 

vnaHvae Linn. 
Pyrgus Hbn., Verz. bek. Schmett. 109, 1820. Type Papilio 

syrichtus Fab. 
Heliopetes Billberg, Enum. Ins. 81, 1820. Type Papilio arsalte 

Linn. 
Syrichtus Boisd., Icones 230, 1833. Type Papilio proto Esp. 
Scelothrix Ramb. Cat. Lep. Andal. I, 63, 1858. Type Papilio 

carthami Hbn. 
Leucoscirtes Scud., Syst. Rev. 52 (73), 1872. Type Syrichtus 

ericetorum Boisd. 
Muschampia Tutt, Brit. Butterflies, i, 218, 1906. Type Papilio 

proto Esp. 
Sloperia Tutt, Brit. Butterflies i, 218, 1906. Type Hesperia 

poggei Led. 
Powellia Tutt, Brit. Butterflies i, 218, 1906. Type Papilio sao 

Berg. 
Favria Tutt, Brit. Butterflies I, 218, 1906. Type, Hesperia cri- 

brellum Eversman. 
Bremeria Tutt, Brit. Butterflies i, 296, 1906. Type Syrichtus 

bieti Obth. 



38 



IOWA STUDIES IN NATURAL HISTORY 



Palpi porreet; second joint with shaggy vestiture in some 
species, smooth in others, and of mixed scales and hair. Anten- 
nae slightly less than one-half as long as primaries! ; club elongate 
oval, flattened, blunt. Costa of primaries more or less flattened ; 
outer margin rounded, sometimes evenly and sometimes more 
strongly toward the apex. Cell less than two-thirds as long as 
wing; vein 5 slightly nearer to 6 than to 4; position of 2 and 
3 very variable. Secondaries broadly rounded with a slight in- 
dication of an anal lobe, to sub-trigonate with the outer margin 




Fig. 11. Hesperia. Antennal clubs: a. niveUa, b. ericetorwm, c. 
and d. tesseUa-ta, two views, e. syrichtus, f. macaira, g. Neuration 
of tesseUata, h. Outer margin of secondary of vyricktus, i. Outer 
margin of secondary of niveUa, j. Costal margin and apex of pri- 
mary of nivella, k. same of syrichtus^ 1. Detail of neuration, pos- 
terior margin of cell of centaureae, m. Same of nweUa 

slightly wavy. Secondary sexual characters of males the costal 
fold, tibial tuft, and abdominal lobes; one or more of these 
characters may be absent. Pig. 11. 

The North American species have hitherto been placed in three 
genera, based chiefly on secondary sexual characters. Barnes 
and McDunnough made a step in advance by avoiding these 
characters in their Contributions in, pp. 121-2, where they re- 
mark: "A better means of separation of Pyrgus [including 
syrichtus, montivaga and philetas] from Hesperia (Scelothrkc) 
than that given by Dyar, and one that would include both sexes 
appears to be found in the palpi; in Pyrgus they are only 
slightly upturned and the clothing under a strong lens is seen 
to be rather even and composed largely of scales with a few hairs 



HESPERIOIDEA OF AMERICA 39 

of equal length intermingled; in Hesperia the palpi are strongly 
upturned and very heavily and roughly clothed underneath with 
long hairs, the scales being confined to the lateral basal portion/' 

It is quite true that this furnishes a good basis for the sep- 
aration of our species, and the general habitus of each group 
is also distinctive, but I have unidentified species of the genus 
from South America which have the habitus of Hesperia (sensu 
B. & McD.) and the palpi of Pyrgus. It seems that the only 
conclusion which will give a well founded classification is to 
adopt the genus Hesperia of many European writers. 

I cannot expect unanimous approval of the sinking of Helio- 
petes, but after examining all of the species carefully and com- 
paring them with those of Hesperia I am unable to point out 
any structure which does not find either its counterpart or a 
similar tendency in the latter genus. The pattern of Hesperia 
is easily traceable in ericetorvm and domiceUa, both above and 
below; in mvella, lawima and macaira the under surface is 
puzzling, but the brown pattern may easily be a modification of 
a superficial vestiture such as that found in syriektus, while the 
black marks are so scanty as to afford no comparison. 

Key to the species 

1. Upper surface of primaries with a broad white discal band or mostly 

white m g 

Band narrow and macular or not evident 2 

2. Spots of primaries subquadrate, well separated 3 

Spots crowded, slender; with an additional row of spots beyond cell. .6 

3. Primaries with a triangular white spot in the angle of vein 2 and the 

cell 4 

This spot absent centaureae 

4. Male with fold; subterminal spots on under surface of secondaries 
deeply creseentic in most specimens, even when reduced in size . . ruraLis 
Male without fold; subterminal spots never deeply creseentic, usually 
poorly defined 5 

5. Under surface of secondaries without distinct contrasts, whitish; mark- 
ings of upper surface usually reduced; a pale, glossy species, .soriptura 
Under surface with contrasting markings; upper surface with macula- 
tion rarely reduced; darker species xanthus, macdurmoughi 

6. Under surface of secondaries with two small submarginal lunules be- 
tween veins 4 and 6 7 

These vague, fused with a marginal white patch or with each other 
tessellata 



40 IOWA STUDIES IN NATURAL HISTORY 

7. Under surface of secondaries very pale, without sharp contrasts . philetas 
Maculation of under surface contrasting; under surface often pow- 
dered with brown scales syrichtus 

8. Basal third of wings dark 9 

This area not more than slightly dark shaded 10 

9. Secondaries with a subterminal esries of large white crescents 

ericeteorum $ 

These crescents much reduced domicella 

10. Cell of secondaries below clear white nivella 

Cell more or less brown 11 

11. Secondaries with broad smooth brown shades below 12 

With a definite yellowish brown pattern, no broad shades, .ericetorwm $ 

12. Inside of outer shade oblique, almost straight.., laviana 

Inside of outer shade curved with outer margin of wing macaira 

1. HESPERIA CENTAUREAE (Plate I, Figure 2) 
Eesperia centaureae Bambur, Faun. Ent. Andal. n, 315, pi. 8, f. 10, 1840. 
Eesperia wyandot Edw., Proc. Ent. Soc. Phil, n, 21, pi. 5, f. 4, 1863. 
Seudder, Butt. New Eng. n, 1542, 1889. 
Holland, Butterfly Book 327, pi. xlvii, f . 13, 1898. 

N. Europe; Labrador, June and July. Ontario, Canada, May, July. 
New Jersey and Virginia, April and May. North Carolina, April. Colo- 
rado, August, 13000 ft. Male with costal fold and tibial tuft. 

2. HESPERIA RURALIS 

Syrichtus ruralis BoiscL, Ann. Soc. Ent. France (2), x, 311, 1852. 
Syrichtus caespitalis Boisd., op. cit., p. 312. 

Eesperia ricara Edw., Proc. Ent. Soc Phil, iv, 203, pi. i, f. 2, 1865. 
Syrichtus petrems Edw., Trans. Am. Ent. Soc hi, 215, 1871. 
Holland, Butterfly Book 328, pi. xlvii, f. 14, 1898. 
Wright, Butterflies of the West Coast* No. 458, pi. xxxi, 1905. 
Oberthiir, Etudesde Lep. Comp. VI, 339, pi. cxxxvii, ff. 1204, 1205, 1212, 
1912 (types of caespitalis and ruralis). 

Western North America from Texas to Alberta, April to July. 

A smaller, darker species than the preceding. Male with fold and tuft. 

3. HESPERIA XANTHUS 

Pyrgus xanthus Edw., Field and Forest ra, 142, 1878. 
Holland, Butterfly Book 328, pi. xlvii, 15, 1898. 

Colorado, July. Xantfms very closely resembles ruralis but most speci- 
mens have the subterminal maculation of the secondaries poorly defined 
and reduced as noted in the key, and the males lack the costal fold. 

4. HESPERIA MACDUNNOVGHI 

Syrichtus macdunnoughi Oberthiir, Etudes ix, (2), 86, pi. cclxiv, f. 2205, 

1913. 
B. & MeD., Contributions in, (2), 122, pi. x, f. 14, 1916. 



HESPERIOIDEA OF AMERICA 41 

There are ftip specimens from Arizona in the Barnes collection under 
this name. Four I am unable to distinguish from xanthus; the remaining 
one has the secondaries pale below, as in scriptura. 

5. HESPERIA SCBIPTURA 

Syrichtus scriptura Boisd. Ann. Soc. Ent. France, (2), x, 312, 1852. 
Holland, Butterfly Book 328, pi. xlvii, f. 12, 1898. 
Wright, Butt. W. Coast 251, pi. xxxi, 459, 1905. 

Oberthiir, Etudes de Lep. Comp. vi, 339, pi. cxxxvh, p. 1206, 1207, 1912 
(type f. 1206). 
New Mexico, California, Colorado, April to June. This species is read- 
ily distinguished by the color of the under surface, its glossy appearance, 
and as a rule by the reduction of the maculation of the secondaries. As 
in the two preceding, the male has the tibial tuft but no costal fold. 

6. HESPERIA SYRICHTUS 

Papilio syrichtus Fab., Syst. Ent. 534, 1775. 

Pyrgus montivagus Beakirt, Proc. Acad. Nat. Sci. Phil. 1866, 334. 
Skinner, Ent. News xvii, 277, pi. xii, 1906. 
Texas and Florida, June and July. 

I hjave seen the type of montivagus in the Strecker collection 
and it is syrichtus, not tessellata as treated by many writers. I 
have a long series from Florida in which the under surface of the 
secondaries has a heavy superficial vestiture of brown scales in 
both sexes. Male with both costal fold and tibial tuft. 

7. HESPERIA PHILETAS (Plate I, Fig. 7) 
Tyrgus pMletas Edw., Papilio I, 46, 1881. 
Arizona and Texas, June to October. 

8. HESPERIA TESSELLATA 
Hesperia tessellata Scud., Syst. Eev. 52, (73), 1872. 
Syricthus communis Grote, Can. Ent. rv, 69, 1872. 
H. montwaga Scud., (not Beakirt) Butt. New Eng. n, 1536, 1889. 
Holland, Butterfly Book 327, pi. xlvii, f. 18, 1898. 
Wright, Butt. W. Coast 250, pL xxxi, 457, 1905. 

Occurs from coast to coast and from the Gulf to northern Canada, April 
to October. 

8a. Mace OCCIDENTALS 
Pyrgus ocddentalis Skinner, Ent. News xvii, 96, 1906. 
Skinner, Ent. News xvn, 277, pi. xii, 1906. 

California, Arizona and Texas. This form is scarcely worthy of a name, 
but may be regarded as a pale southwestern geographical race. I have not 
looked for differences in the genitalia. 



42 IOWA STUDIES IN NATUEAL HISTORY 

9. HESPERIA DOMICELLA 

Syriehtus domieella Eriehson, Schomb., Reise. n. Guiana in, 604, 1848. 
Pyrgus nearcfws Edw., Papilio n, 26, 18£2. 
Holland, Butterfly Book 327, pi. xlvii, f. 19, 1898. 

Arizona, August and September. 

This and the four following species, formerly placed in Eeliopetes t have 
both the costal fold and tibial tuft in the males. 

10. HESPERIA ERICETORUM (Plate I, Pig. 4 £ , 6 $ ) 
Syriehtus ericetorum Boisd., Ann. Soe. Ent. France (2)| x, 313, 1852. 
Syriehtus alba Edw., Proc. Ent. Soc. PhO. vi, 206, 1866. 
Wright, Butt. W. Coast 250 pi. xxxi, f. 456, 1905. 
Oberthur, Etudes de Lep. Comp. vi, 339, pi. dxxxvn, f. 1210, 1912 (type). 

California, April to August. Arizona, July. 

11. HESPERIA MACAIRA 

Pyrgus macaira Beakirt, Proc. Acad. Nat. Sci. Phil. 1866, 334. 
Syriehtus oceanus Edw., Trans. Am. Ent. Soc. m, 213, 1871. 
Leuoochitonea locutia Hew., Exot. Butt., Leuch. t. 2, ff. 19, 20, 1875. 
Brownsville, Texas; June. 

12. HESPERIA LAVIANA 

Leucoehitonea laviana Hew., Desc. Hesp. 48, 1868. 
Leucoehitonea pastor Felder, Verh. z.-b. Ges. Wien xix, 476, 1869. 
Pyrgus leca Butler, Trans. Ent. Soc. London 1870, 510. 
Texas, June and July. 

13. HESPERIA NIVELLA 

Leucoscwtes nivea Scud, (not niveus Cr.), Syst. Eev. 52 (73), 1872. 
Leueoscvrtes nivella Mab., Bull. Soc. Ent. Belg. xxvii, lv, 1883. 
Leucoehitonea orbigera Mab., Le Nat. x, 242, 1888. 
Biol. Cent.-Am., Bhop. II, 446, pi. 90, ff. 22-24, 1897. 
Brownsville, Texas; June. 

Genus SYSTASEA Butler 
Systasea Butler, Edw., Can. Ent. ix, 120, 1877. Type, Leucoeh- 
itonea pvlverulenta Folder. 
Celotes G. & S., Biol. Cent.-Am., Rhop. n, 452, 1899. Type 
Pholisora nessus Edw. 
Palpi porreet, moderate; second joint slightly hairy; third 
slightly drooping in dried specimens. Antennae about one-half 
as long as primaries; club moderate, curved, fusiform, rather 
blunt. Primaries with a costal fold in the male; costa slightly 
curved; outer margin curved, with a shallow excavation before 




HBSPERIOIDEA OF AMERICA 43 

anal angle; inner margin slightly concave, scarcely longer than 
outer; U. D. C. short, M. D. C. and L. D. C. about equal. Vein 
2 twice as far from 3 as from base of cell. 
Secondaries very irregular with emargina- 
tions opposite cell and before anal angle. As a 
rule the antennal club of nessus is slightly 
larger in proportion to the shaft than that of 
pulverulenta but it varies in each species. In 
spite of the difference in appearance of the 
two species I can find nothing to warrant 
placing them in different genera. It may be 
that tropical species exist which will fill in 
the gap between them. Fig. 12. 

Key to the species 

Terminal portion of wings with brown dashes 

Fig. 12. Neuration of ° 

Systasea pulverulenta nessus 

Feld This area without dashes pulverulenta 

1. SYSTASEA NESSUS 
Pholisora nessus Edw., Can. Ent. ix, 192, 1877. 
Spilothyrus notdbilis Strecker, Lep. Rhop. 131, 1878. 
Biol. Cent.-Am., Rhop. n, 452, pi. 91, ff. 27, 28, 29, 1899. 
Holland, Butterfly Book 329, pi. xlvii, f. 17, 1898. 
Texas and Arizona, April to August. 

2. SYSTASEA PULVERULENTA 

Leucochitonea pulverulenta Feld., Verh. z.-b. Ges. Wien xix, 478, 1869. 
Hesperia zampa Edw., Trans. Am. Ent. Soe. v, 207, 1876. 
Biol. Cent.-Am., Rhop. n, 413, pi. 87, ff. 24, 25, 1895. 
Holland, Butterfly Book 329, pi. xim, f. 1, 1898. 
Arizona, July and August. Texas, April and October. 

Genus PHOLISORA Scudder 
Pholisora Scud., Syst. Rev. 51, (72), 1872. Type PapiUo catul- 

lus Fab. 
Staphylus G. & S., Biol. Cent.-Am., Rhop, n, 429, 1896. Type 

Helios asccHaphus Staud. 
Bolla Mabille, Gen. Ins. xvn, 72, 1903. Type — pullata Mab. 
Hesperopsis Dyar, Jn. N. Y. Ent. Soc. xin, 118, 1905. Type 
Thanaos alpheus Edw. 
The species grouped in this genus offer a troublesome problem 



44 



IOWA STUDIES IN NATURAL HISTORY 



in generic distinctions. Bolla was separated from Pholisora by 
Mabille on the basis of the more pointed club of the antennae. 
Dyar associates Hesperopsis in his description with Hesperia 
instead of Pholisora and calls attention to the long palpi, es- 
pecially the long third joint, and th;e absence of the costal fold. 
I have bleached and mounted structures of alpheus, libya, catul- 
lus, ceos and hayhurstii and have found the following things to 
be true : In alpheus the third joint of the palpi is about three- 
fifths as long as the second and both are slender; the vestiture 
of th'e third joint makes it appear about twice as long as it really 




Fig. 13. Pholisora. Palpi: a. alpheus, b. libya, c. catuUus, d. ceos, e. hay- 
hwstii. Antennal clubs: f. libya, g. catvXius, h. ceos, i. hayhurstii,\ j. Neur- 
ation of hayhurstii, k. and 1. Outer margins of wings of ceos and catuUus 



is. Libya, associated with alpheus, has the third joint relative- 
ly shorter, both second and third thicker, the vestiture of the 
third similar and that of the second deeper. The entire ap- 
pendage looks more like the palpus of catullus than alpheus. 
The eleventh vein of the primaries of alpheus arises well before 
the middle of the cell, while in all of the other species it arises 
near the middle, usually slightly beyond. Ceos differs from 
catullus in the relatively longer third palpal point and thicker 
second, and in the short vestiture of the third. In the shape of 
the wings it is intermediate between catullus and hayhurstii and 
farthest removed from alpheus. The antennal club is thickest in 
alpheus and most slender in ceos, but if the same aspect be com- 
pared the species are seen to differ but slightly. From this it 



HESPERIOIDEA OF AMERICA 45 

appears that there is no closer bond between alpheus and libya 
than between libya and catullus, while ceos varies in the opposite 
direction from catullus but in the structure of the palpi shows 
some affinity with the first two species. For these reasons I 
prefer to regard the group as one genus with a wide range of 
structural variation. In this sense Pholisora may be character- 
ized as follows: 

Palpi exceeding the front by the length of the head or more ; 
second joint oblique, rather long, with moderate scaly vestiture ; 
third porrect, slender, long. Antennae about one-half as long 
as primaries; club more or less tapered and blunt. Wings 
rounded ; secondaries with or without a slight indention in the 
outer margin at the end of the cell and sometimes with a slight 
lobe at the anal angle. Neuration variable ; vein 11 of primaries 
never much beyond middle of cell and vein 2 about the same 
distance from base of cell and vein 3 ; U. D. C. long, over half 
the length of M. D. C. Male with or without costal fold, never 
with tibial tuft. Fig. 13. 

Key to the species 

1. Primaries with a transverse series of dark dashes alpheus 

Primaries without dark dashes 2 

2. Secondaries with white spots below 3 

Secondaries immaculate 4 

3. Under surface pale, yellowish; upper surface of primaries with trans- 
verse row of spots complete lena 

Under surface usually less pale and with numerous white spots when 
upper surface is heavily spotted; possibly! not distinct from the pre- 
ceding . Ubya 

4. Head and palpi ochreous ceos 

Head and palpi dark, concolorous with body 5 

5. Upper surface of an even shade 6 

With faint, dark, transverse bands. 7 

6. Undersurface brownish black catullus 

Under surface grayish glaucous mejicanus 

7. Primaries with hyaline subapical spots hayhurstii 

No such spots brennus 

1. PHOLISORA ALPHEVS 

Thanaos alpheus Edw., Trans. Am. Ent. Soe. v, 206, 1876. 
Pholisora oricus Edw., Can. Ent. xi, 51, 1879. 
Biol. Cent.-Am., Rhop. n, 442, pi. 90, f . 15, 1897. 
Holland, Butterfly Book 331, pi. xlv, f . 2, 1898. 



46 IOWA STUDIES IN NATURAL HISTORY 

Wright, Butt. W. Coast 235, pi. xxx, f. 407, 1905. 
Arizona, New Mexico, and Colorado, March to July. 

2. PHOLISORA LIBYA 

Heteropterus libya Scud., Bull. Geol. Surv. Terr., iv, 258, 1878. 
Holland, Butterfly Book 331, pi. xlviii, f. 14, 1898. 
Wright, Butt. W. Coast 234, pi. xxx, f. 406, 1905. 

California, June and October. Utah, July. Arizona, April. 

3. PHOLISORA LENA 

Ancyloxypha lena Edw., Can. Ent. xrv, 5, 1882. 

There is one specimen in the Barnes collection which appears to be lena 
and is possibly a good species. It is rather pale in color, but this may be 
due to fading. On the upper surface it resembles a heavily maculate speci- 
men of libya while below it has only a few spots. Libya, when heavily 
spotted above, is also well marked below. The one specimen is from Miles 
City, Montana, the type locality. 

4. PHOLISORA CATULLUS 

Hesperia catuZlus Fab., Ent. Syst. m, (i), 348, 1793. 
Seud., Butt. New Eng. n, 1519, 1889. 
Holland, Butterfly Book, 330, pi. xlv, f . 4, 1898. 
Wright, Butt. W. Coast 234, pi. xxx, f. 403, 1905. 

United States and Southern Canada, April to October. 

5. PHOLISORA MEJIC ANUS 
Nisoniades mejicanus Reakirt, Proc Acad. Nat. Sci. Phil. 334, 1866. 
Biol. Cent.-Am., Bhop. n, 441, pi. 90, ff. 11, 12, 1897. 

Las Vegas, N. M. 

The upper surface is practically the same as oatullus but the glaucous 
gray appearance of the lower surface is unmistakable. 

6. PHOLISORA CEOS 

Pholisora ceos Edwards, Papilio n, 140, 1882. 
Biol. Cent.-Am., Bhop. n, 432, pi. 89, ff. 7, 8, 1896. 
Arizona, July. 

7. PHOLISORA HAYHURSTII 
Hesperia hayJmrstii Edw., Trans. Am. Ent. Soc. in, 22, 1870. 
Scudder, Butt. New Eng. in, p. 1857, 1889. 
Biol. Cent. -Am., Bnop. n, 433, pi. 89, f. 16, gen., 1896. 
Holland, Butterfly Book, 331, pi. xlviii, f. 16, 1898. 

Florida, north and west to Minnesota and Texas, March to October. 
Some specimens have merely a trace of the subapical spots. 



HESPERIOIDEA OF AMERICA 



47 



8. PHOLISORA BRENNUS 
Nisoniades hrewMU G. & S., Biol. Cent.-Am., Rhop. n, 434, pi. 89, f. 23, 

gen., 1896. (Mabille in litt.). 
Skinner, Ent. News xn, 171, 1901. 

I do not know this species. It is said to occur in our country along the 
Mexican border. 

Genus EANTIS Boisduval 
Eantis Boisd., Spec. Gen. pi. 13, f. 6, 

1836. Type Vrbanus vetiCs 

thraso Hiibner. 
Palpi porrect; second joint rath- 
er large, densely and smoothly 
scaled; third small, distinct. Ant- 
ennae about one-half as long as pri- 
maries; club extremely slender and 
long, the tip curved. Costa of pri- 
maries rounded in basal half and al- 
most straight to apex ; outer margin 
excavated below apex, thence well 
rounded to anal angle; cell about 
three-fifths as long as wing; vein 5 
intermediate between 4 and 6. Sec- 
ondaries roughly quadrate; costa 
and inner margin curved, outer bent to an obtuse angle between 
3 and 4 and produced between 6 and 7. Fig. 14. 

1. EANTIS THRASO (Plate I, Fig. 8) 
TJrbanus vetus thraso Hbn., Samml. exot. 

Schmett, i, t. 151 ff. 1-4, 1807-16. 
Hesperia tamenund Edw., Trans. Am. Ent. Soc 

in, 215, 1871. 
Biologia Cent.-Am., Rhop. II, 405, pi. 87, f. 7, 

$ gen., 1895. 

Texas, May and July. 

Genus XENOPHANES Godman & 
Salvin 
Xenophanes G. & S., Biol. Cent.-Am., 
Rhop. ii, 387, 1895. Type Papilio 

Fig. 15. Xenophanes tryxus tryXUS Cramer. 

Cramer, a. Club of antenna. t-»i*it ., . ■, . . . , . 

b. Outline of wings Palpi oblique ; third joint moderate, 




Fig. 14. Eantis thraso Hbn. a. 
Club of antennae, b. Neuration 




48 IOWA STUDIES IN NATURAL HISTORY 

conical, not concealed. Club of antennae very slender, curved. 
Costa of primaries slightly curved; apex rectangular; inner 
margin nearly straight, outer slightly convex between apex and 
vein 2, thence nearly straight to anal angle. Costal fold absent. 
Cell less than two-thirds as long as wing ; vein 5 intermediate ; 
2 slightly nearer to base of wing than to 3. Secondaries broadly 
rounded ; inner margin nearly straight, anal angle sub-rectangu- 
lar; outer margin slightly concave between veins 4 and 6 and 
very slightly between lb and 2. Vein 5 present, very weak; 2 
about as near to base of wing as to 3. Fig. 15 

1. XENOPHANES TBYXUS (Plate I, Fig. 3) 
Papilio tryxus Cramer, Pap. Exot. iv, 87, pi. cccsxxxrv, G, H, 1781. 
Biol. Cent. -Am., Bhop. n, 387, pi. 85, f. 18, $ gen., 1895. 

Brownsville, Texas, July. 

The species is easy to recognize in, our fauna by the many hyaline spots 
an the discal area of both wings. 

Geneus MELANTHES Mabille 
Melanthes Mab., Gen. Ins. xvii, 80, 1904. Type 
Nisoniades brunnea H.-S. 
In general structure this genus is close to Than- 
aos but the secondaries are relatively a little larger 
the outer margin of the primaries longer and more 
oblique, the apex more produced and rectangular 
and the anal angle more broadly rounded. The 
antennae are moderate and the club fusiform, 
sharply pointed and evenly curved. Fig. 16. 

Fig. iT. Meian- 1. MELANTHES BRUNNEA (Plate I, Fig. 10) 
f^Sd fn- Nisoniades brunnea H.-S., Corr.-Blatt. Eegensb. xvm, 172, 
tenna. b. Outline 1864. 
of wings 

Skinner, Ent. News xiv, 110, 1903. 

I nave this species from Cuba but Dr. Skinner 's record, Sugar Loaf Key, 
Fla., is the only one which has reached me concerning its occurrence in the 
United States. The even brown shade of the wings, with a few hyaline 
points on the primaries, is characteristic. 

Genus CHIOMARA Godman & Salvin 
Chiomara G. & S., Biol. Cent.-Am., Rhop. n, 453, 1899. Type. 
Achlyodes mithrax Mosehler. 
Similar to Thanaos ; outer margin of primaries only two- thirds 




HESPERIOIDEA OF AMERICA 



49 



as long as inner, strongly curved; vein 11 arising just beyond 
middle of cell and reaching casta before end of cell. Mate 
with tibial tuft but no costal fold. Fig. 17. 

Gesta appears to belong in Thanaos; 
the figure of the genitalia in the Biologia 
is distinctly of the Thanaos type. 




Fig. 17. ChiomMra asychis 
Cramer. Neuration of primary 



1. CHIOMARA ASYCHIS 

Papilio asychis Cramer, Pap. Exot. iv, 87, pi. 

ccoxxxiv, E, F, 1781. 
Pyrgus georgma Reakirt, Proc. Acad. Nat. Sci. 

Phil. 1868, 88 (fide G. & S.). 
Biol. Cent.-Am., Rhop. n, 453, pi. 91, ff. 1, 2, 3, 1899; p. 741, 1901. 

Texas, Arizona, October. I have one specimen from Corumba, Brazil, 
taken in March. 



Genus THANAOS Boisduval 
Thanaos Boisd., Ieones 240, 1832-3. Type Hesperia juvenalis 

Fab. 
Seudder and Burgess, Proc. Bost. Soc. Nat. Hist, xm, 282-306, 

pi. 1870. 
Skinner, Trans. Am. Ent. Soc. xl, 195-221, 1914. 

Palpi large, exceeding front 
by about length of head; vesti- 
ture shaggy; third joint stout 
and roughly scaled. Antennae 
moderate; club fusiform, curv- 
ed. Costa of primaries slightly 
convex, flattened along fold ; out- 
er margin in most species evenly 
rounded, in some more strongly 
curved opposite cell; relative 
width of primaries variable. Cell 
scarcely two-thirds as long as 
wing; vein 5 intermediate, 7 to 
11 in the distal third of the 
cell, 11 ending beyond end of cell 
U. D. C. less than half as long 
Fig. is. Thanaos. a. Neuration of juven- as M. D. C. Secondaries vari- 

alis, b. Outer margins of wings of i i • jr. t_ -i . 

funeraiis able m size and shape, broad out- 




50 IOWA STUDIES IN NATURAL HISTORY 

er margin rounded to wavy ; costal fold present except in gesta. 
Hind tibiae of male with tufts in a few species. Fig. 18. 

A key to the species of TJumaos based on superficial characters 
is of comparatively little use, for the species are closely related 
and there are few which do not intergrade with others. The fol- 
lowing key is based on fairly typical specimens, but in a long 
series I have found many which could not be definitely placed 
by it, so I have thought it wjise to speak a word of caution re- 
garding its use. The genitalia of the males offer the ultimate 
means of determination, and since they can usually be examined 
fairly well by brushing away the scales from the tip of the 
abdomen and using a hand lens or binocular, their use in class- 
ification of the species should be practiced. 

Key to the species 

1. Fringes of hind wings white 13 

Fringes never white 2 

2. Primaries without distinct hyaline spots, sometimes with one or two 

clouded spots next to costa 3 

Primaries with at least a subapical row of hyaline spots (or with very 
dark wings, terentvus $) 5 

3. Expanse under thirty mm ; # with tibial tuft ; apex of primaries rather 

sharply angled icelus 

Expanse usually over thirty mm; no tuft in male; apex of primaries 
more obtuse and outer margin more rounded 4 

4. Gray powdering heavier toward apex of primaries; distribution gen- 
eral brizo 

Primaries usually evenly powdered with gray scales; inner part of 
median band usually obsolete or broken; Southwestern and Calif ornian 

species hwgessi, lacustra 

Powdering scant or absent; dark marks of primaries united to form 
broad bands; under surface without distinct spots; $ with tuft but 
no fold ; southwestern species gesta 

5. Under surface of secondaries with two pale subapical spots, or at least 

a trace of them 6 

No subapical spots 7 

6. Gray vestiture mostly of fine hairs propertms 

Gray vestiture scaly juvenalis 

7. Hyaline spots large, at least a trace of one in end of cell; dark mark- 
ings of primaries contrasting (9), or spots' lacking; primaries with 

little or no gray vestiture ($) horatius 

Spots small, color very dark, or gray powdering conspicuous 8 

8. Very dark, sometimes with a brownish patch at end of cell; maeula- 

tion obscure ; $ with tibial tuft terentius 

Tuft absent; marks more or less contrasting 9 




PLATE II 
MALE GENITALIA OP THANAOS 

The figures are mere outlines of the claspers viewed from the outside, omitting 
spines and other vestiture. The right and left drawings of each figure are the right 
and left claspers, respectively. 

1. Thanacs icelus Lint. 2. Thanaos brizo Bd. & Lee. 3. Thanaos burgessi 
Skinner. 4. Thanaos lacustra Wright. 5. Thanaos persius Scudder. 6. Than- 
aos martialis Scudder. 7. Thanaos juvenalis Fab. 8. Thanaos propertius Scud. 
& Burg. 9. Thanaos horatius Scud. & Burg. 10. Thanaos terentius Scud. & 
Burg. 11. Thanaos pacuvius Lint. 12. Thanaos scudderi Skinner. 13. Than- 
aos clitus Edw. 14. Thanaos tristis Boisd. 15. Thanaos funeralis Scud. & Burg. 






HESPERIOIDEA OF AMERICA 51 

9. Dark marks conspicuous, secondaries checkered; fresh specimens with 

a purplish lustre . ■. . . . . martialis 

Not such insects 10 

10. Larger, marks more or less obscured toward base of primaries 

persius, pemiyra 

Usually smaller, marks more evenly distinct over entire wing 11 

11. Fringes usually evenly colored 12 

Fringes pale tipped; western form persius f race afranius 

12. Secondaries with pale spots below clear cut lucilius 

Spots absent or diffuse; western species callidus 

13. Tufts of dark scales in base of white fringe all along outer margin 

scudderi, pacuvws 

Rarely with a suggestion of such tufts 14 

14. Primaries narrower than normal; $ with tibial tuft funeralis 

Primaries normal, no tuft tristis, clitus 

Under surface of secondaries with some white inside of fringe 

tristis, var. tatvus 

1. THANAOS ICELVS 

Nisoniades icelus Scudder & Burgess, Proc. Bost. Soc. Nat. Hist, xin, 288, 

1870. 
Lintner, 23rd Ann. Rep. N. Y. St. Cab. Hist. 162, pi. 7, ff. 5, 6, 1872. 
Scudder, Butt. New Eng. n, 1507, 1889'. 
Holland, Butterfly Book 333, pi. xlviii, 17, 1898. 

Arizona, Colorado, Massachusetts, Pennsylvania and southern Canada; 
May to July. Athabaska and Mackenzie, June (Cary). North Carolina, 
April (Brimley & Sherman). 

2. THANAOS BRIZO 

Thanaos brizo, Boisd. & Lee, Lep. Am. Sept. pi. 66, 1833. 
Scudder, Butt. New Eng., n, 1500, 1889. 
Holland, Butterfly Book 332, pi. xlv, f. 7, 1898. 

Atlantic coast to Rocky Mountains, Gulf to Southern Canada; April to 
July. Eastern specimens of this species are easy to identify, but it is 
difficult to separate burgessi, lacustra and brizo when all are from the 
same locality. 

2a. race SOMNUS 
Nisoniades somnus Lintner, Papilio i, 73, 1881. 

Florida, February and April. This is merely a very dark form of brizo. 

3. THANAOS BURGESSI 

Thanaos burgessi Skinner, Trans. Am. Ent. Soc xl, 203, 1914. 
Arizona and New Mexico; March, April and August. 

4. THANAOS LACUSTRA 

Nisoniades lacustra Wright, Butt. W. Coast 253, pi. xxxn, 480, 1905. 
California, June. This is not a form of brizo, as has been stated, but is 



52 IOWA STUDIES IN NATURAL HISTORY 

more nearly related to ourgessi, though the genitalia differ enough to war- 
rant regarding it as a distinct species. 

5. THANAOS GESTA 

Thanaos gesta H.-S., Corr.-Blatt Regensb. xvii, 142, 1863. 
Thanaos iwvisus Butler & Bruce, Cist. Ent. I, 114, 1872. 
Biol. Cent.-Am., Rhop. n, 455, pi. xci, ff. 7, 8, 9, 1899. 
Nisoniades llano Dodge, Can. Ent. xxxv, 78, 1903. 
Texas and Arizona; July. 

6. THANAOS PERSIUS 

Nisoniades persius Scudder, Proc Ess. Inst, in, 170, 1863. 
Scudder, Butt. New Eng. n, 1468, 1889. 
Holland, Butterfly Book 334, pi. xlviii, f. 1, 1898. 

The typical form has an expanse of about thirty-five millimeters and is 
dark and obscurely marked, especially on the basal half of the wings. It 
occurs throughout the United States and north into Alaska; May to August. 

6a. race PEBNIGBA 
Thanaos pernigra Grinnell, Ent. News xvi, 34, 1905. 
California, July. A very dark Pacific Coast race. 

6b. race AFRANIUS 
Nisoniades afranius Lintner, 30th Rep. N. Y. Mus. Nat. Hist. 175, 1877. 

California, Utah, Colorado, Arizona; May, July and August. Afranius 
does not exceed thirty millimeters and is rather distinctly marked and gray 
powdered; the fringes are pale, sometimes almost white, at their tips. 

6c. race LUCILIUS 
Nisoniades lucilius Scudder & Burgess, Proc. Bost. Soc. Nat. Hist, xin, 

287, 1870. 
Lint., 23rd Rep. N. Y. St. Cab. Nat. Hist. 164, pi. 7, ff. 1, 2, 1872. 
Scudder, Butt. New Eng. n, 1458, 1889. 
Holland, Butterfly Book 333, pi. xlviii, f. 10, 1898. 

Northeastern United States and southeastern Canada, April and May. 
Dr. W. T. M. Forbes has kindly identified slides of genitalia in my possession 
as lucilius, which he regards as a species. I am unable to agree with this 
and follow Skinner in placing it as a race of persius, though a careful 
study of the early stages may show it to be distinct. It is usually smaller 
than persius and more distinctly marked. 

7. THANAOS CALLIDUS 

Thanaos callidus Grinnell, Ent. News xv, 114, 1904. 
MeDunnough, Ent. News xxviii, 232, 1917. 

After an eventful and troublesome career callidus has at last been run 
down by Dr. MeDunnough. It proves to be a good species, treated as 
lilius Dyar by Skinner in his "Studies in the Genus Thanaos.' ' The two 



HESPERIOIDEA OP AMERICA 53 

names may apply to the same thing, but in that case callidus has priority. 
The genitalia resemble those of pacuvius. California, June and July. 

8. THANAOS MABTIALIS 

Nisoniades martialis Scudder, Trans. Chi. Acad. Sci. I, 335, 1869. 

Scudder, Butt. New Eng. n, 1493, 1889. 

Holland, Butterfly Book 335, pi. xlviii, f. 4, 1898. 

New York, west to Colorado and north into Canada; May, July, August. 

Dr. Forbes tells me that eastern specimens of this species have a brassy 
lustre, but all which I have seen from the middle west were decidedly pur- 
plish. The unusually bright, contrasting pattern is the most reliable char- 
acteristic. 

ab. AUSONIUS 
Nisoniades ausonms Lint., 23rd Bep. N. Y. St. Cab. Nat. Hist. 166, pi. 7, 

ff, 11, 12, 1872. 
Scudder, Butt. New Eng. n, 1498, 1889. 

Ausonms lacks the subapieal hyaline spots and has the transverse series 
of dark dashes unusually prominent. It was described from a single speci- 
men taken at Center, N. Y., on May 12, 1871, and has never been taken 
since. 

9. THANAOS JVVENALIS 

Hesperia juvenalis Fab., Ent. Syst. in, (i), 339, 1793. 
Nisoniades juvenis Hbn., Verz. bek. Sehmett. 108, 1820. 
Nisoniades costalis Westw. & Hew., Gen. Diurn. Lep. n, 519, pi. 79, f. 3, 

1852. 
Nisoniades ennms Scud. & Burg., Proe. Bost. Soc. Nat. Hist, xni, 296, f. 

9, 1870. 
Scudder, Butt. New Eng. n, 1476, 1889. 
Holland, Butterfly Book 335, pi. xlviii, f. 11, 1898. 

Wright, Butt. W. Coast 252, pi. xxxn, 462$, 469 £ (not $ tristis), 1905. 
Atlantic coast to Rockies, Gulf to Northern Canada; May to August. 

10. THANAOS PROPERTIUS 

Nisoniades propertms Scud. & Burg., Proc. Bost. Soc. Nat. Hist, xm, 298, 

f. 11, 1870. 
Nisoniades tibullus Scud. & Burg., op. cit., p. 299, f. 12. 
Wright, Butt. W. Coast 252, pi. xxxn, f. 463, 1905. 

Texas, Arizona, California and north into Canada; June, July and Au- 
gust. The abundance of hairy gray vestiture in specimens which have not 
been badly rubbed is very characteristic. 

10a. race BOBEALIS 
Thanaos propertms, var. borealis Cary, Proc. XJ. S. N. M. xxxi, 455, 1906. 
Type one male from North Nahanni River, Mackenzie, June 4, 1904. Ap- 
parently this is a dark race with the pale maculation greatly reduced. 



54 IOWA STUDIES IN NATURAL HISTORY 

11. THANAOS HORATIUS 

Nisoniades horatius Scud. & Burg., Proc. Bost. Soc. Nat. Hist, xin, 301 f . 

13, 1870. 
Nisoniades virgilius Scud. & Burg., op. cit. p. 302, f. 14. 
Nisoniades petronms Lint., Papilio i, 70, 1881. 
Scudder, Butt. New Eng. n, 1486, 1889. 
Holland, Butterfly Book 336, pi. xlviii, f. 15, 1898. 

Florida and Texas, north to Colorado and Minnesota; May, July, Au- 
gust, October. The females are conspicuously marked but the males resem- 
ble juvenalis closely. 

12. THANAOS TERENTIUS 

Nisoniades terentms Scud. & Burg., Proc. Bost. Soc. Nat. Hist, xin, 292, 

f. 6, 1870. 
Nisoniades ovidius Scud. & Burg., op. cit. 295, f. 8. 
Nisoniades naevius Lintner, Papilio i, 69, 1881. 
Scudder, Butt. New Eng. n, 1490, 1889. 
Holland, Butterfly Book 336, pi. xlviii, f. 3, 1898. 

Florida, April, May and July. South Carolina, May. Mississippi, Au- 
gust. The very dark, even color of this species is easy to recognize, and as 
a rule the brown patch on the primaries is conspicuous. 

13. THANAOS PACUVIUS 

Nisoniades pacuvws Lint., 30th Rep. N. Y. Mus. Nat. Hist. 172, 1878. 
Holland, Butterfly Book 336, pi. xlviii, f. 9, 1898. 

California, Arizona, New Mexico and Colorado; March, May, June and 
August. 

14. THANAOS SCUDDERI 

Thanaos scudderi Skinner, Trans. Am. Ent. Soc. xl, 215, 1914. 
Thanaos paouvms G. & S. (not Lintner), Biol. Cent.-Am., Rhop. n, 458, pi. 
91, ff. 16, 17, 1899. 
Texas and Arizona, July and August. I am unable to separate this 
species from pacuvvus except by the structure of the male genitalia. Skin- 
ner points out a slight difference in the hyaline spots. 

15. THANAOS CLITUS 

Thanaos clitus Edw., Papilio n, 180, 1882. 

Thanaos maestus G. & S., Biol. Cent.-Am., Ehop. n, 457, t. 91, f. 18, <£ gen., 

1899. 
Holland, Butterfly Book 336, pi. xlv, f. 8, 1898. 
Arizona, May to August; California and Colorado. 

16. THANAOS TRISTIS 

Thanaos tristis Boisd., Ann. Soc. Ent. France (2), x, 311, 1852. 
Oberthiir, Etudes ix, (1), pi. CCXL, f. 2081, 1913, figure of type. 
California, June and August. Arizona. 



HESPERIOIDEA OF AMERICA 55 

form TATIUS 
Thanaos tatws Edw., Papilio n, 179, 1882. 
Arizona, April, June, July, September. 

17. THANAOS FUNERALIS 

Nisoniades funeralis Scud. & Burg., Proc. Bost. Soc Nat. Hist, xin, 293, 

f. 7, 1870. 
Holland, Butterfly Book 336, pi. XLvni, f. 12, 1898. 
Wright, Butt. W. Coast 253, pi. xxxn, f. 468 and 464 (not clitus), 1905. 

California, June. Arizona, Texas and Colorado, June and July. March 
in the far south. The rather narrow primaries, of a dull, brownish color, 
and the broad secondaries are unlike the other species of the genus. 

The two following species cannot be fixed at present to any known form: 

18. THANAOS PLAUTUS 
Nisoniades plautus Scud. & Burg., Proc. Bost. Soc. Nat. Hist, xin, 304, 
f. 16, 1870. 
Described from Florida. The figure of the genitalia has some points of 
similarity with the genitalia of jwenalis. 

19. THANAOS LILIUS 

Thanaos lilius Dyar, Proc. XJ. S. N. M. xxvii, 788, 1904. 

Dyar states (Jn. N. Y. Ent. Soc. xm, 122) that the genitalia 
of litiius are similar to those of UbulVws (t=propertiv£) , while 
Skinner's description of them in his " Studies" suggests those of 
callidus, which was not correctly fixed at the time when his paper 
was written. Apparently lilius will fall before one of these two 
species, but an examination of the genitalia of the type will be 
necessary to settle the matter. I am greatly indebted to Dr. 
McDunnough for his notes on these species, for all data which 
I am able to give here are based on his researehjesi. 

Genus TIMOCHARES Godman & Salvin 
Timochares G. & S., Biol. Cent.-Am., Rhop. n, 417, 1896. Type 
L.euco6kit(me<A trifasaiata Hew. 
Palpi moderately large, much as in Thanaos, with a hairy 
second joint and a stout, conical third joint. Antennae less 
than one-half as long as primaries; club moderate, fusiform, 
curved. Costa of primaries convex, with a long fold in the 
male; apex rectangular, subtruncate; outer margin rounded 
from vein 6 to anal angle. Secondaries trigonate; inner margin 
about as long as wing measured through cell; outer margiti 



56 IOWA STUDIES IN NATURAL HISTORY 

wavy. Neuration practically as in T. juvenilis. T. fwneroMs 
is structurally very close to this genus, but the apex of the pri- 
maries is never distinctly subtruncate and the anal angle is 
much more broadly rounded. 

1. TIMOCHARES RUPTIFASCIATUS 

Antigonus ruptifasoiatus Plotz, Jahrb. Nass. Ver. xxxvn, 27, 1884. 
Biol. Cent.-Am., Rhop. n, 418, pi. 88, pp. 1, 2, 1896. 

I have seen one male from Brownsville, Texas, in the Barnes collection. 

Genus GRAIS Godman & Salvin 
Grais G. & S., Biol. Cent.-Am., Rhop. n, 381, 1894. Type An- 
astrus stigmaticus Mab. 
The structure of this genus is very similar to that of the pre- 
ceding, but the cell of the primaries is of almost equal width 
throughout, and is approximately equal to the distance between 
cell and costa. The male has neither costal fold nor tibial tuft. 

1. GRAIS STIGMATICUS 

Anastrus stigmaticus Mab., Bull. Soc. Ent. Belg. xxvi, Lrv, 1883. 
Antigonus fumosus Plbtz, Jahrb. Nass. Ver. xxxvn, 26, 1884. 
Biol. Cent.-Am., Rhop. II, 381, pi. 84, ff. 24, 25, 26, 1894. 
Kerrville, Texas; September. 

Subfamily PAMPHILINAE 

Palpi usually upturned; in a few genera porrect. Antennae 
very variable in length ; club usually short and stout with a very 
slender apiculus but sometimes longer; apiculus sometimes thick 
or absent. Primaries more or less trigonate; secondaries tri- 
gonate to rounded and lobed. Neuration as in the Hesperiinae 
but with the L. D. C. usually tubular and vein 5 curved toward 
the base in the primaries, arising nearer to 4 than to 6. Front 
tibiae usually with the epiphysis; middle tibiae usually with 
conspicuous spines; hind tibiae usually with two pairs of spurs 
and never with a tuft. In the species of group A the spinula- 
tion of the mid tibiae furnishes a convenient means for separat- 
ing the insects from the Hesperiinae. Males often with stigma 
on primaries. 

The loss of the apiculus in the Pamphilinae seems to have been 
brought about by its gradual reduction, a process of evolution 
which is nicely illustrated by the transition from OUgorm to 



HESPERIOIDEA OF AMERICA 57 

Chaerephon in Group B. I regard this as furnishing the phylo- 
genetic basis for the separation of Group A from the Hesper- 
iinae, which makes it necessary to explain their resemblance by 
parallel or convergent evolution. 

In place of the two groups into which the Pamphilinae have 
commonly been divided I believe that a modification of the sys- 
tem used in the Biologia will be of greater convenience. I have 
therefore divided our fauna into four groups which are char- 
acterized as follows: 

Group A. Palpi porrect. Vein 5 of primaries straight, in- 
termediate between 4 and 6 ; cell less than two-thirds as long as 
wing. Club of antennae blunt. Carteracephalus and Butleria. 

Group B. Palpi upturned ; third joint long and slender. An- 
tennae short; club blunt. Vein 5 of primaries curved slightly 
toward 4 at base. Cell less than two-thirds as long as wing. 
Aneylaxypha, Oarisma, Adopaea and Copaeodes. 

Group C. Palpi appressed or oblique; third joint moderate 
or small, long in Arnblyscirtes. Antennae with a slender api- 
culus in most genera. Vein 5 of primaries curved at base, us- 
ually arising much nearer to 4 than to 6. Cell less than two- 
thirds as long as wing. All North American genera not includ- 
ed in A, B and D. 

Group D. Palpi closely appressed, smoothly and deeply 
scaled; third joint small. Club of antennae stout, with a fine, 
abruptly constricted apiculus. Vein 5 arising much nearer to 
4; cell about two-thirds as long as wing and with at least a rudi- 
ment of a recurrent vein. Thespieus, Calpodes and Prenes. 

GROUP A 
Key to the genera 

Hind tibiae with one pair of spurs :Carterocephalus 

Hind tibiae with two pairs of spurs Butleria 

Genus CARTEROCEPHALUS Lederer 
Carteracephalus Led., Verh. z.-b. Ges. Wien n, 26, 49, 1852. 

Type: Papilio palaemon Pallas. 

Second joint of palpi oblique, loosely clothed with long hairs; 
third slender, moderately long, enveloped by hairs of second. 
Antennae less than one-half as long as primaries; club large, 



58 



IOWA STUDIES IN NATURAL HISTORY 



j^mib 




elongate ovate, flattened on its posterior surface, blunt. Pri- 
maries trigonate with the outer margin rounded, rather narrow. 

Vein 5 intermediate between 4 
and 6; L. D. C. not tubular, 
faint. Secondaries rounded; 
apex prominent and anal angle 
slightly produced. Hind tibiae 
with one pair of spurs; mid- 
dle tibiae spined. Males with- 
out secondary sexual struc- 
tures. Fig. 19. 

. 1. CARTEROCEPHALUS 
PALAEMON 

Papilio palaemon Pallas, Reise I, 

471, 1771. 

Papilio paniscus Fab., Syst. Ent. 
Fig. 19. Butleria pvrus Edw. a. Club of - 01 -__- 
antenna, b. Hind tibia, c. Neueration, d. Ool, 1770. 
Hind tibia of Carter ocephalus palaemon Papilio brontes Denn. & Schiff. 

Wien Verz. 160, 1776. 
Hesperia mandan Edw., Proc. Ent. Soc. Phil, n, 20, pi. v, f. 1, 1863. 
Hesperia mesapano Scud., Proc. Bost. Soc. Nat. Hist, xi, 383, 1868. 
Cyclopides skada Edw., Trans. Am. Ent. Soc. in, 196, 1870. 
Stereoptes skada Edw., Trans. Am. Ent. Soc. in, 214, 1871. 
Scudder, Butt. New Eng. n, 1569, 1889. 
Elwes & Edwards, Rev. Or. Hesp. 167, 1897. 
Holland, Butterfly Book 342, xlvti, f. 1, 1898. 

Canada, Mountains of New England and Rocky Mountains; June. Cal- 
ifornia, Montana. Europe and Asia. Fort Providence, Mackenzie, July 
(Cary). Yukon Territory (Winn). 

Genus BUTLERIA Kirby 
Butleria Kirby, Syn. Cat. 624, 1871. Type Carterooephalus 

exornatus Felder. 
Dalla Mab., Gen. Ins. xvii, 107, 1904. Type Cyclopides eryonas 
Hew. 
Very similar in structure to Carterocephalus but with two 
pairs of spurs on the hind tibiae. Fig. 19. 

Butleria was first characterized by Watson (P. Z. S. 1893, 79) 
but according to Mabille his description does not fit the geno- 
type. Mabille in turn characterized the genus to correspond 
with the typical species in vol. xvii of the Genera Inseetorum, 



HESPERIOIDEA OF AMERICA 59 

page 106, at the same time dividing it and naming one part 
Dalla. Such differences as he mentions between the two seem 
to be slight and transitional through the series of species in- 
cluded, and I therefore sink Dalla. The description of Dalla 
does not apply to our species as well as Mabille's diagnosis of 
Butleria, so if the genera be separated again there is a possi- 
bility that Butleria, and not DaMa will still be applicable in 
our region. 

Key to the species 

Under surface of secondaries immaculate pirus 

With a number of small pale spots microsticta 

With a few large spots polingi 

1. BUTLERIA PIRUS 

Pholisora pirus Edw., Field and Forest m, 119, 1878. 
Colorado, Utah, Arizona; June, July. 

2. BUTLERIA MICROSTICTA 

Butleria microsticta G. & S., Biol. Cent. -Am., Rhop. n, 464, pi. 92, ff, 1, 
2, 3, 1900. 
I have seen no specimens; the species is said to occur near the Mexican 
border. 

3. BUTLERIA POLINGI 

Pyrgus polmgi Barnes, Can. Ent. xxxn, 44, 1900. 
Arizona, June and July. 

GROUP B 
Key to the genera 

1. Wings broadly rounded. Ancyloxypha 

Wings more or less trigonate 2 

2. All wings trigonate; male without stigma; club of antennae 

about as long as shaft Oarisma 

Males with stigma ; secondaries, at least, rounded ; club not 
as long as shaft 3 

3. Secondaries rounded, primaries trigonate; club small 

Copaeodes 

Outer margin of primaries more oblique and rounded; club 
large, relatively long Adopaea 



60 



IOWA STUDIES IN NATURAL HISTORY 



^^9 



Genus ANCYLOXYPHA Felder 
Ancyloxypha Feld., Verh. z.-b. Ges. Wien xn, 477, 1862. Type 
Hesperia numitor Fab. 
Palpi upturned; second joint normal, deeply sealed; third 
slender, pointed, almost as long as second. Antennae much less 

than one-half as long as primar- 
ies ; club blunt, moderately large. 
Costa of primaries rounded at 
base, less so in outer half ; outer 
margin broadly rounded, cell 
slightly less than three-fifths as 
long as wing ; vein 5 nearer to 4 
than to 6; 2 and 3 near end of 
cell. Secondaries rather long 
through cell, rounded; outer 
margin slightly emarginate be- 
o& *V«£K te *3SS K S »;• tween veins 4 and 6. Male with- 

outer line shows limit of vestiture, c. Pal- 




pus, d. Neuration 



out stigma. Fig. 20. 



1. ANCYLOXYPHA NUMITOR 

Eesperia mrnitor Fab., Ent. Syst. in, (i), 324, 1793. 
Thymelicus puer Hbn., Verz. bek. Sehmett. 113, 1820. 
Heteropterus marginatus Harris, Ins. Inj. Veg., 3rd ed., 308, 1862. 
Scudder, Butt. New Eng. n, 1558, 1889. 
Holland, Butterfly Book 345, pi. xlvii, f. 2, 1898. 

Atlantic coast west to Texas, north into Canada; May to August. 

The disk of the primaries is black below, while that of the following 
species is ruddy fulvous. 

ab. LONGLEYI 
Ancyloxypha longleyi French, Can. Ent. xxix, 80, 1897. 

Described from Illinois. A form in which the primaries are glossy 
black above. 

2. ANCYLOXYPHA ARENE 

Heteropterus arene Edw., Trans. Am. Ent. Soc. in, 214, 1871. 

Copaeodes myrtis Edw., Papilio n, 26, 1882. 

Apaustus leporma Plotz, Stett. Ent. Zeit. xlv, 166, 1884, (fide G. & S.). 

Holland, Butterfly Book 346, pi. XLvn, f. 11, 1898. 

Biol. Cent.-Am., Ehop. n, 472, pi. 92, ff. 35-38, 1900. 

Arizona, August. Differs from numitor in the absence of black from 
the under surface of the primaries. 



HESPERIOIDEA OF AMERICA 



61 




Genus OARISMA Scudder 
Oarisma Scudder, Syst. Rev. 54, (75), 1872. Type Hesperia 

pawesheik Parker. 
Paradopaea 6. & S., Biol. Cent.-Am., Rhop. n, 469, footnote, 1900. 

Palpi as in Ancyloxypha. Anten- 
nae much less than one-half as long as 
primaries; club enlongate obovoid, ^^ g 

blunt, as long or nearly as long as 
shaft. Costa of primaries straight ex- 
cept at base and apex ; outer margin 
curved only opposite cell ; entire wing 

trigonate; cell about three-fifths as ^ 

long as wing ; vein 5 near 4 at base ; 
3 near end of cell ; 2 about as far from 
3 as from base of wing, variable. Sec- 
ondaries trigonate, all margins slight- 
ly rounded and anal angle very 
slightly lobed. Male without stigma. *£$^ 
Fig. 21. x< *^ 

Fig. 21. Oarisma garita Reakirt: 
7T , , 7 . a. Club of antenna, d. Neuration. 

Key 10 trie Species Jopaeodes auraaitiaca Hew. b. Club 

i -rr , - » . of antenna, c. Palpus 

1. under surface of secondaries with white 

veins on a dark ground before vein lb powesheik 

Veins not much paler than ground color 2 

2. Upper surface bright yellow-fulvous edwardsi 

Upper surface fuscous, variably powdered with yellow-fulvous, .garita 

1. OARISMA GARITA 

Hesperia garita Eeakirt, Proc. Ent. Soc. Phil, vi, 150, 1866. 
Thymelicus hylax Edw., Trans. Am. Ent. Soc. in, 274, 1871. 
Paradopaea calega G. & S., Biol. Cent.-Am., Rhop. n, pi. 92, ff . 26-29, 1900. 
Paradopaea garita G. & S., Biol. Cent.-Am., Rhop. n, pi. 92, ff. 23-24, 1900. 
Oarisma powesheik G. & S., (not Parker) Biol. Cent.-Am., Rhop. n, 469, 

1900. 
Holland, Butterfly Book 343, pi. xlvii, f. 3, 1898. 
Wright, Butt. W. Coast pi. xxx, f. 408, 1905 (not lena Edw.) 

Manitoba, Montana, Colorado, Idaho, Arizona; July. 

Calega G. & S. looks in the figure as if it might be a good species but in 
the text the authors refer it to garita. They also erroneously refer their 
figures of garita to powesheik. 

2. OARISMA EDWARDSI 

Thymelicus edwardsi Barnes, Can. Ent. xxrx, 42, 1897. 



62 IOWA STUDIES IN NATURAL HISTORY 

Paradopaea garita G. & S. (not Reakirt) Biol. Cent.-Am. Bhop. in, pi. 92, 
f. 25 $ genitalia, 1900. 

Colorado, Arizona and New Mexico; June and July. 

I have seen the type of this species and the pale upper surface is very 
different from garita. 

3. OARISMA POWESHEIK 

Hesperia powesheHc Parker, Am. Ent. & Bot. n, 271, 1870. 
Thymelicus garita Plotz (not Eeakirt), Stett. Ent. Zeit. xlv, 287, 1884. 
Scudder, Butt. New Eng. in, 1859, 1889. 
Holland, Butterfly Book 343, pi. xlvii, f. 4, 1898. 

Described from thirty-one males and two females taken June 21, 1870, 
at Grinnell, Iowa. It has also been taken in Colorado and South Dakota, 
and I have observed it personally so near to the Minnesota line in Iowa 
that it probably enters that state. Michigan (Wolcott). 

Genus ADOPAEA Billberg 
Adopaea Billb., Enum. Ins. 81, 1820. Type Papilio thawmas 
Hufn. 

Similar to Copaeodes but with the antennal club larger and 
relatively longer, and with a rudiment of the apiculus. The 
outer margin of the primaries is more oblique, relatively shorter, 
and more deeply sinuate. The stigma of the male is similar. 

This genus has been incorrectly used in the past in our fauna 
for eunus and ivrighti-, it is represented only by an introduced 
species. 

1. ADOPAEA LINEOLA 
Papilio lineola Ochs., Schmett. Eur. i, (2), 230, 1808. 
Morris, British Butterflies, 153, pi. 70, 1890. 
Spuler, Schmett. Eur. t. 18, ff. 6a, 6b, 1910. 
47th Rep. Ent. Soc. Ont. 142, 1917. 

Introduced from Europe. The reference in the report of the Entomolog- 
ical Society of Ontario records its capture at London, Ontario, on July 1, 
1910, and every year from then until the date of the publication. 

Genus COPAEODES Speyer 
Copaeodes Speyer, Edw. Cat. Lep. 49, 64, 1877. Type Heterop- 
terns procris Edw. 
Palpi upturned ; second joint densely scaled ; third fine, point- 
ed, not quite as long as in Ancyloxypha. Antennae scarcely 
two-fifths as long as primaries; club rather small, stout, blunt. 
Primaries trigonate; costa straight except at base and apex; 
outer margin slightly sinuate; anal angle almost rectangular. 



HBSPERIOIDEA OF AMERICA 63 

Secondaries rounded, slightly lobed at anal angle. Wings more 
elongate in female. Primaries of male with a slender, longi- 
tudinal stigma. Cell of primaries about three-fifths as long as 
wing ; vein 5 arising much nearer to 4 than to 6. Fig. 21. 

1. COPAEODES AURANTIACA 

Ancyloxypha aurantiaca Hew., Desc. Hesp. 45, 1868. 

Eesperia waco Edw., Trans. Am. Ent. Soe. n, 122, 1868. 

Eeteropterus minima Edw., Trans. Am. Ent. Soe. in, 196, 1870. 

Eesperia procris Edw., op. cit. 215. 

Thymelicus macra Plotz, Strett. Ent. Zeit. xlv, 284, 1884. 

Copaeodes Candida Wright, Proc. Cal. Aead. Sei. (2), in, 34, 1890. 

Copaeodes nanus Watson, (not H.-S.), Proc. Zool. Soe. London, 1893, 98 

(fide G. & S.). 
Holland, Butterfly Book 345, pi. xlvii, f . 9, 1898, 
Biol. Cent.-Am., Rhop. n, 473, pi. 92, ff. 39-42, 1900. 
Wright, Butt. W. Coast 236, pi. xxxi, ff. 409, 411, 1905. 
Skinner, Ent. News xxix, 150, 1918. 

Arizona, May, July, August and September. Texas, California, March, 
May, August. 

I cannot agree with Dr. Skinner that this and the following are but one 
species, but as he suggests, rayata may fall before the female of procris, 
in which case the latter name might be restricted to the female type and 
retained as a species. 

2. COPAEODES BAY AT A 

Copaeodes rayata B. & McD., Contributions n, (3), 100, pi. in, ff. 1, 2, 1913. 

San Benito, Texas; June and July. 

I have seen the types of this species and it is abundantly distinct from 
aurantiaca. The pale ray is variably distinct, but the veins are darker 
than the ground color and of a somewhat rusty shade on the lower surface 
of the secondaries. The size is smaller than aurantiaca. 

GROUP C 
Key to the genera 

1. Club of antennae blunt or with a rudiment of the apiculus 

Chaerephon 

Club of antennae with a sharp apiculus, sometimes very 
short 2 

2. Vein 5 of primaries well curved toward base, arising con- 
spicuously nearer to 4 than to 6 3 

Vein 5 but slightly curved, only a little nearer to vein 4 at 
base; L. D. C. weak .11 



64 IOWA STUDIES IN NATURAL HISTORY 

3. Antennae scarcely longer than width of thorax. .Hylephila 
Antennae distinctly longer 4 

4. Mid tibiae with spines 5 

Mid tibiae without spines Atrytone 

5. Apiculus of antennae shorter than thickness of club or not 

abruptly constricted 6 

Apiculus at least equal to thickness of club, slender; either 
abruptly constricted or distinctly longer than thickness of 
club 9 

6. Primaries apically produced and secondaries lobed ; apiculus 

very short 7 

Primaries and secondaries moderate; apiculus usually mod- 
erately long 8 

7. Male stigma slender; wings of female moderate PamphMa 

Male stigma a large blotch ; wings of female similar to those 
of male Atalopedes 

8. Vein 2 of primaries slightly nearer to base of wing than to 
vein 3. Secondaries well marked with yellow fulvous; see 

description Augiades 

Vein 2 variably nearer to 3 ; when doubtful, secondaries with 
little fulvous, at the most a transverse band; see descrip- 
tion Polites 

Vein 2 immaterial. Club of antennae very stout, with a 
fine apiculus, or moderate with a thick apiculus Poanes 

9. Apiculus slender, about twice thickness of club Oligoria 

Apiculus shorter or thick 10 

10. Apiculus slender ; male stigma large, with large gray scales ; 

under surface fuscous Catia 

Apiculus tapered, not abruptly constricted; male without 

stigma ; under surface not fuscous Powrxes 

Apiculus slender, variable, male stigma variable. Under 
surface gray powdered to dark brown Atrytonopsis 

11. Male stigma large; maculation yellow Epiphyes 

Stigma not large ; maculation not pale yellow 12 

12. Apiculus fine; shorter than thickness of club Lerodea 

Apiculus longer, or wings immaculate 13 

13. Third joint of palpi long (ex. nanno) ; fringes checkered 

Amblyscirtes 

Third joint short; fringes not checkered 14 



HESPERIOIDEA OF AMERICA 



65 



14. Vein 5 almost intermediate between 4 and 6 ; under surface 

with purplish lustre. Lerema 

Vein 5 considerably nearer to 4; under surface otherwise 
Mastor 

Genus CHAEREPHON Godman & Salvin 
Chaerephon G. & S., Biol. Cent-Am., Rhop. n, 474, 1900. Type 
Pamphila citrus Mab. 
Second joint of palpi upturned, 
deeply scaled; third small, oblique, 
smooth. Antennae less than one-half 
as long as primaries ; club large, obo- 
void, subacute but without a reflexed 
apiculus. Costa of primaries straight 
except at base ; apex produced, round- 
ed acute in males, less sharp in fe- / ^~ -^, ' 
males; outer margin rounded in cen- 
ter and straighter nearer apex and 
anal angle,though almost evenly 
rounded in some females. Secondar- 
ies rounded, lobed at anal angle in 
male, slightly so in female. Both 

, , n , , Fig. 22. Chaerephon. a. Club of 

wings appear shorter and broader in antenna of rhesus, b. Paipus of 

.-. i .-, . .-, « i t\ • eunus, c. Club of antenna of 

the male than m the temale. Jrn- eunus, d. Neuration of eunus 
maries of male with a faint stigma 

composed of an oblique bar above vein 2 followed by two small 
round patches in line below the vein. Fig. 22. 

Key to the species 

1. Wings yellow-fulvous eunus, urrighti 

Wings mostly fuscous 2 

2. Under surface gray powdery simius 

Under surface more or less yellowish 3 

3. Yellow of under surface of secondaries interspersed with, dark patches; 

maculation distinct rhesus 

Yellow pale, dull, even ; maculation obscure carus 

1. CHAEREPHON EUNUS 
Copaeodes eunus Edw., Papilio I, 47, 1881. 
Holland, Butterfly Book, pi. xlVii, f. 10, 1898 (as wrighti). 
Wright, Butt. W. Coast 237, pi. xxxi, ff. 412, 414, 1905. 
California, June. 




66 



IOWA STUDIES IN NATURAL HISTORY 



2. CHAEREPHON WBIGHTI 

Copaeodes wrighti Edw., Can. Ent. xiv, 152, 1882. 

Wrighti is probably a synonym of eunus; the original description fits 
ewws, the type localities are in the same part of California, and we do not 
know of two species of these general characteristics. Both of these have 
been erroneously placed in Adopaea in the past, whereas Adopaea is close- 
ly related to Copaeodes and eunus is not at all similar in structure. 

3. CHAEREPHON RHESUS 

Pamphila rhesus Edw., Field and Forest in, 116, 1878. 
Biol. Cent.-Am., Rhop. n, 475, pi. 93, ff. 5-7, 1900. 
Skinner, Ent. News xi, pi. n, ff. 19, 20, 1900. 
Kellogg, Am. Ins. pi. ix, ff. 19, 20, 1904. 
Colorado, Arizona. 

4. CHAEREPHON CARUS 

Pamphila earns Edw., Can. Ent. xv, 34, 1883. 
Texas and Arizona, May, July and September. 

5. CHAEREPHON SIMIUS 

Amblyscvrtes simius Edw., Trans. Am. Ent. Soc. ix, 6, 1881. 
Holland, Butterfly Book 341, pi. xlvii, f. 8, 1898. 
Colorado; Sioux County, Nebraska, July. 
This is one of our rarer species. I am indebted to Mr. Leussler for a 
specimen taken in Sioux County, Nebraska, the only one in my possession. 

Genus PAMPHILA Fabricius 
Pamphila Fab., 111. Mag. vi, 287, 1807. Type PapiUo comma 

Linn. 
Ocytes Scud., Syst. Rev. 55, (76), 1872. 

Scud. 
Anthomaster Scud., Syst. Rev. 57, (78), 1872. 

leonardus Harris. 



Type Erynms metea 
Type Hesperia 




jsS0^ 






Fig. 23. Pamphila and Augiades, a. Palpus of 
A. snowi, b. Club of antenna of P. viridis £ , 
c. Same, female, d. Palpus of P. viridis, e. 
Same, denunded, f. iSection of palpus of A. 
sylvanus; outer line shows limit of vestiture, 
g. Palpus of A. napa 



Palpi upturned; second 
joint with a smooth vesti- 
ture of scales and some 
hairs; third about one-half 
as long as second but part- 
ly concealed. Antennae 
less than one-half as long 
as primaries; club large 
with a very small apiculus 
which is a little longer in 
the female. Costa slightly 



HESPERIOIDEA OF AMERICA 67 

emarginate to slightly convex; outer margin slightly sinuate to 
evenly rounded, usually more rounded in the female. Secondaries 
rounded, slightly lobed at anal angle. In all of the species the 
wings of the females are longer and more rounded than those of 
the males. Vein 5 of primaries arising very near to 4; 3 near 
end of cell; 2 about intermediate between 3 and base of wing; 
cell slightly over three-fifths as long as wing. Vein 7 of second- 
aries slightly nearer to end of cell than to 8. Mid tibiae spiny. 
Male stigma slender, strong, extending from base of vein 3 to 
basal third of vein 1 and made up of a long piece in front of 
vein 2 and a shorter piece behind 2 which is set just outside of 
the first but is continuous with it. Fig. 23. 

Key to the species 
This key is not to be regarded as a means of ultimate identification; in 
Pamphila no key can be sufficient in itself, for many of our species and 
forms intergrade to such an extent that only a practiced eye can even sort 
them properly. The key to the forms of comma included here is based 
on specimens in the Barnes collection which have been compared with the 
types, and so may be relied on for typical specimens. It will not, how- 
ever, suffice for the placing of the multitude of intermediate forms which 
occur in large series. 

1. Under surface of secondaries with alternating greenish and fuscous 

areas ; veins white on disk urwas 

Under surface evenly colored ; veins not white 2 

2. Upper surface fuscous with reduced, poorly defined, pale spots; under 

surface of secondaries with a pale band metea 

Upper surface more or less fulvous or with well defined spots, or lower 
surface with separate spots 3 

3. Under surface of secondaries with a pale ray in the cell morrisoni 

With or without a pale spot in cell 4 

4. Under surface of secondaries yellow to brown with an oblique band 
of uniform, confluent white spots posterior to vein 6; sometimes with 

a single spot before this band colvmibia 

Spots making up band, when present, not confluent, unequal, irregular- 
ly placed or with more than one spot before vein 6. Under surface 
usually greenish in forms which are likely to confuse 5 

5. Under surface of secondaries with sharply defined white spots or yel- 
lowish to greenish with the bent macular band traceable 6 

Under surface without sharply defined white spots; immaculate or with 
traces of separate spots, usually poorly defined or not white 13 

6. Under surface of primaries fuscous; spots on secondaries small and 

rounded seminole 

Under surface of primaries with some fulvous or spots on secondaries 
otherwise 7 



68 IOWA STUDIES IN NATURAL HISTORY 

7. Spot on under surface of secondaries just behind vein 2 nearer base 
of wing than rest of band or absent. Band sometimes too much mod- 
ified to show this difference 8 

This spot on a line with rest of band or outside of it ; band well marked, 
white viridis 

8. Spots not confluent, their size variable; under surface usually dark 

with sparse over-scaling woodgatei 

Spots usually confluent or over-scaling dense 9 

9. Upper surface bright with sharp contrasts; costal area of primaries 

fulvous; white spots of lower surface very large and bright juba 

Upper surface with a variable diffusion of fuscous; when maeulation 
is sharp, the other characters differ. Spots below moderate to greatly 
reduced, white or yellowish 10 

10. Maeulation below yellow but not reduced sassacus 12 

Maeulation white or greatly reduced 11 

11. Maeular band with one spot before vein 7, one behind vein 2 followed 
by a trace of a second; band irregular; superficial vestiture gray- 
green nevada 

Band equally contrasting but more regular and abbreviated, usually 
with no spot before 7 and only one reduced spot behind 2; superficial 

vestiture green Colorado 

Spots dull white ; superficial vestiture golden brown manitoba 

Under surface of secondaries very smooth in appearance, yellow; spots 

white idaho 

Spots greatly reduced, white assiniboia 

Spots greatly reduced, yellowish oregonia 

12. Under surface of secondaries pale ; maeulation faint sassacus 

Under surface dark; maeulation contrasting. sassacus, race manitoboides 

13. Under surface of secondaries dark red-brown with pale, cream-white 

spots leonardus 

Under surface otherwise 14 

14. Pale maeulation above very diffuse; pale area in end of cell of pri- 
maries showing two pale nuclei, always vague, .sassacus, race dacotae 
Cell of primaries with two sharply defined spots in end, or with these 
indistinguishably fused 15 

15. Disk of secondaries above with fulvous spots ( $ ) ; under surface very 

dark (9) attains, race seminole 

Disk more or less broadly fulvous ( $ ) ; under surface pale ($).... 16 

16. Under surface of secondaries yellow-fulvous, with or without vague 

traces of large spots meskei 

Under surface of a lighter shade, more or less yellow; spots small 
or absent 17 

17. Southern species, Florida, Texas, Ohio? attains 

Prairie species, Iowa, Nebraska, Dakota, Montana, and California 
ottoe, pawnee, pawnee race montana 



HESPERIOIDEA OF AMERICA 69 

1. PAMPHILA UNCAS 
Eesperia uncas Edw., Proc. Ent. Soc. Phil, n, 19, pi. v, f . 3, 1863. 
Hesperia ridingsi Reakirt, Proe. Ent. Soc. Phil. VI, 151, 1866. 
Hesperia axius Plotz, Stett. ent. Zeit. xliv, 213, 1883. 
Scudder, Butt. New Eng. in, 1862, 1889. 

Holland, Butterfly Book 349, pi. xlvii, ff. 27, 28, 1898. 
Colorado and Arizona, June and July. 

2. PAMPHILA LASU8 
PampMla lasus Edw., Papilio iv, 54, 1884. 

Described from Arizona. I do not know the species. 

3. PAMPHILA LICINUS 

Pamphila licinus Edw., Trans. Am. Ent. Soc. in, 275, 1871. 
I do not know this species. 

4. PAMPHILA METE A 

Hesperia metea Scud., Proc. Ess. Inst, in, 177, 1862. 

Scudder, Butt. New Eng. n, 1650, 1889. 

Holland, Butterfly Book 348, pi. xlvii, ff. 33, 34, 1898. 

New Jersey, New York, Massachusetts, New Hampshire and Rhode Isl- 
and; May and June. This species is readily distinguished by its dark 
color, vague, whitish maeulation and the tendency of the macular band on 
the under surface of the secondaries to be produced along the veins. The 
spots making up this band are neither separate nor very bright as in the 
other dark colored species. 

5. PAMPHILA M0RBI80NI 

Pamphila morrisoni Edw., Field and Forest in, 116, 1878. 
Hesperia morissoni Plotz, Stett. ent. Zeit. xliv, 215, 1883. 
Biol. Cent.-Am., Rhop. II, 478, pi. 93, ff. 9, 10, 1900. 

Colorado, May. 

This is a small, bright species which is readily recognized by the elonga- 
tion of the white mark in the cell of the secondaries below. 

6. PAMPHILA COLUMBIA 

PampMla Columbia Scud., Syst. Rev. 56, (77), 1872. 

PampMla sylvanoides Scud., (not Boisd.) Mem. Bost. Soc. Nat. Hist, n, 

(3), 351, pi. x, f. 22 (type), pi. xi, pp. 15, 17, 1874. 
PampMla California Wright, Butt. W. Coast 241, pi. xxxi, 423, 1905. 
Thymelicus erynnioides Dyar, Jn. N. Y. Ent. Soc. xv, 50, 1907. 

California, April and October. 

All of the specimens in the Barnes collection have the band very even, 
as mentioned in the key; in Wright's figure it appears to be somewhat re- 
duced toward the anal angle, but the color of the under surface of the 
secondary is characteristic. 



70 IOWA STUDIES IN NATURAL HISTORY 

7. PAMPHILA NEVADA (Plate I, Fig. 9) 
Pamphila nevada Scud., Mem. Bost. Soc. Nat. Hist, n, 347, pi. x, ff. 1-4, pi. 

xi, ff. 3, 4, 1874. 
Wright, Butt. W. Coast 240, pi. xxx, pp. 418, c, 419, b, c, 421, b, e, 1905. 

I follow Dr. McDunnough in making this species distinct from comma. 
There is some difference in the male genitalia and if we restrict nevada 
to the typical form the under surface differs as noted in the key. Arizona 
to Northern Canada. 

8. PAMPHILA COMMA 

Pamphila comma Linn., Syst. Nat. 484, 1758. 

Comma is a European species and does not occur in its typical form in 
this country. 

8a. race COLOBADO PI. I, fig. 11 
Pamphila Colorado Scud., Mem. BJost. Soc. Nat. Hist, n, 349, pL x, ff. 16, 
17, 18, pi. xi, ff. 1, 2, 1874. 
Arizona north to Washington, California. 

In the typical form the under surface of the secondaries is bright green 
with the band pure white, short, rather even, and the basal marks united 
to form a U. 

8b. race MANITOBA 
Pamphila manitoba Scud., Mem. Bost. Soc. Nat. Hist, n, 351, pi. x, ff. 8- 

11, pi. xi, ff. 7, 8, 1874. 
Scud., Butt. New Eng. n, 1646, 1889. 

Pamphila manitoba, var. laurentina Lyman, Can. Ent. xxrv, 57, 1892. 
Northwestern United States and Western Canada. 
The typical form is golden brown beneath with whitish maculation. 

8c. race IDAHO 
Pamphila Colorado, var. idaho Edw., Can. Ent. xv, 148, 1883. 
Wright, Butt. W. Coast 241, pi. xxxi, f. 422, 1905. 

California, Oregon, north into Canada. 

The smooth, yellow appearance of the under surface of the secondaries 
is characteristic. 

8d. race ASSINIBOIA 
Pamphila manitoba, var. assiniboia Lyman, Can. Ent. xxiv, 57, 1892. 
Begina, Canada. 

8e. race OBEGONIA Plate i, fig. 13 
Pamphila oregonia Edw., Can. Ent. xv, 150, 1883. 

Nevada, west to the coast and north into Canada. 

The maculation of the under surface is similar to that of assmiboia but 
yellowish instead of white. 



HESPERIOIDEA OF AMERICA 71 

9. PAMPHILA RURICOLA 

Hesperia ruricola Boisd., Ann. Soe. Ent. France (2), x, 315, 1852. 

Described from California. 

Many things have been referred to this species, which may be one of the 
forms of comma. I know nothing of the type nor of authentic specimens. 

10. PAMPHILA JUBA 

Hesperia comma Boisd. (not Linn.), Ann. Soc. Ent. France (2), x, 313, 

1852. 
PampMla juba Scud., Syst. Rev. 56, (77), 1872. 
Scudder, Mem. Bost. Soe. Nat. Hist, n, 349, pi. x, ff. 19, 20, pi. xi, ff. 5, 

6, 1874. 
Wright, Butt. W. Coast 239, pi. xxx, ff. 417, 418b # (not viHdis $ ), 1905. 
Oberthiir, Etudes ix, (1), p. 43, pi. COXL, f. 2082 (comma Bdv.). 
Utah, Colorado, Nevada, California; May and June. 

11. PAMPHILA WOODGATEI 

Pamphila woodgatei Williams, Ent. News xxv, 266, 1914. 

Arizona, Texas and New Mexico; September and October. 

This has been placed as a variety of juba but I believe that it is dis- 
tinct. I have had no males for dissection. 

12. PAMPHILA VIBIDIS (Plate I, Fig. 12) 
Pamphila juba var. viridis Edw., Can. Ent. xv, 147, 1883. 

Colorado, Arizona, New Mexico and Texas; June and September. 

The form of the macular band in this species is unique and apparently 
constant. 

13. PAMPHILA LEONARDUS 

Hesperia leonardus Harris, Ins. Inj. Veg., 3rd ed., 314, f. 138, 1862. 

Scudder, Butt. New Eng. n, 1673, 1889. 

Holland, Butterfly Book 349, pi. xlvii, ff. 35, 36, 1898. 

New York, Rhode Island, Massachusetts, west to the Mississippi; occa- 
sional in eastern Iowa; August and September. Scudder records it from 
Ontario and Florida, the latter in March and April (Butt. New Eng. n, 
1676-7). 

14. PAMPHILA CABELUS 
Pamphila cabelus Edw., Trans. Am. Ent. Soc. ix, 4, 1881. 

Described from Nevada. 

This is another of our lost species of Pamphila. Apparently it belongs in 
the ottoe group. 

15. PAMPHILA HARPALUS 

Pamphila harpalus Edw., Trans. Am. Ent. Soc. ix, 3, 1881. 
Described from Nevada. 
The same may be said of this as of the preceding. 



72 IOWA STUDIES IN NATURAL HISTORY 

16. PAMPHILA ATTALUS 

Pamphila attains Edw., Trans. Am. Ent. Soc. in, 276, 1871. 

Scudder, Butt. New Eng. n, 1653, 1889. 

Holland, Butterfly Book 349, pi. xlvii, f. 23, 1898. 

Florida, Texas. In the Barnes collection several specimens are labelled 
Ohio, and Scudder (Butt. New Eng. n, 1655) mentions records from Wis- 
consin, Iowa and New Jersey. I think that the middle western records 
are more likely to be pawnee or ottoe. Southern specimens of attalus are 
darker than these two species, and have the spots of the upper surface dark- 
er and more reddish. 

16a. race SEMINOLE 
Ocytes seminole Scud., Syst. Eev. 55, (76), 1872. 
Erynnis attalus quaiapen Scud., Butt. New Eng. 1655, 1889. 
PampMla slossonae Skinner, Ent. Amer. VI, 138, 1890. 

Florida, April to June, October. 

Seminole is very dark both above and below. The maculation is re- 
stricted in the male, and the under surface of the primaries very slightly 
marked with fulvous, while in the female all spots are whitish and the 
under surface is not marked with fulvous. Scudder describes quaiapen as 
a female form of attalus. 

17. PAMPHILA MESKEI 

Pamphila mesJcei Edw., Can. Ent. ix, 58, 1877. 
Pamphila straton Edw., Papilio, i, 78, 1881. 

Florida and Texas. 

I have seen only three males in the Barnes collection. These resemble 
attalus above; beneath the secondaries are yellow-fulvous, immaculate in 
one of the three specimens and with traces of large, diffuse, pale spots in 
the other two. 

18. PAMPHILA OTTOE 
Eesperia ottoe Edw., Proe. Ent. Soc Phil, vi, 207, 1866. 
Scudder, Mem. Bost. Soc. Nat. Hist, n, 348, pi. x, f. 6, pi. xi, f. 13, 1874. 
In the typical form the males are tawny above with a very narrow ter- 
minal border of fuscous, and compared specimen^ in the Barnes collec- 
tion have the under surface bright yellow. I have taken a species at Sioux 
City, Iowa, in late July and early August which I have placed as ottoe 
and whieh is distinguished by the ochraceous under surface and the exten- 
sion of the pale area of the upper surface along the veins into the moder- 
ately broad fuscous terminal border. True pawnee occurs in this locality 
at a different season. Specimens in the Barnes collection are from Mon- 
tana. 

19. PAMPHILA PAWNEE 

Eesperia pawnee Bodge, Can. Ent. vi, 44, 1874. 

Montana, July. Colorado, September. Omaha, Neb., June. South Da- 



HESPERIOIDEA OF AMERICA 73 

kota, Sioux City, Iowa, late June and early July, late August and early 
September. Described from Dodge County, Neb. 

The under surface is usually immaculate yellow, in the female sometimes 
grayish and usually with small pale spots. The spots on tne upper surface 
of the primaries in the female are very pale, and this sex closely resembles 
attains. The males of this species may be distinguished by the more ex- 
tensive pale areas of the upper surface and their lighter shade. 

19a. race MONTANA 
Pamphila pawnee subsp. montana Skinner, Ent. News xxn, 413, 1911. 

California, Colorado, Montana. 

A specimen in the Barnes collection which has been compared with the 
type is much darker than normal pawnee, both above and below. 

20. PAMPHILA SASSACUS 
Eesperia sassacus Harris, Ins. Inj. Veg., 3rd ed., 315, 1862. 
Scudder, Butt. New Eng. n, 1641, 1889. 
Holland, Butterfly Book 348, pi. xlvi, f. 13, 1898. 
Holland, Butterfly Book pi. xlvii, f. 44, 1898, (not sylvanoides) . 
Kellogg, Am. Ins. pi. x, f. 5, 1904. 

New Jersey, New York and Connecticut, westward into Iowa; June, 
July, August. 

20a. race MANITOBOIDES 
Pamphila manitoboides Fletcher, Rep. Ent. Soc. Ont. for 1888, p. 85, 1889. 

Ontario, Canada. 

Dr. W. T. M. Forbes has called my attention to this relationship of 
manitoboides, which seems so close that I am adopting his arrangement. 
Formerly it has been called a distinct species or a form of comma, but 
it is identical with sassacus except in the darker color and greater contrast 
of the markings of the lower surface. 

20b. race DACOTAE 
Pamphila sassacus, subsp. dacotae Skinner, Ent. News xxn, 412, 1911. 

South Dakota, June. Sioux City, Iowa. 

I have seen paratypes of both sexes in the Barnes collection, and in the 
males the only difference which I can formulate between this form and 
sassacus is a general darkness of color and obscureness of the under sur- 
face. The females have the markings of the upper surface greatly reduced 
and diffuse, and the lower surface grayish with small, indefinite spots. 

21. PAMPHILA HORUS 

Hesperia horus Edw., Trans. Am. Ent. Soc. in, 277, 1871. 
Barnes & MeDunnough, Contributions' IV, (2), 80, 1918. 

Type locality Dallas, Texas. Apparently this speeies belongs in Pam- 
phila, but I know nothing of it except from the description and Barnes and 
MeDunnough 's note. 



74 



IOWA STUDIES IN NATURAL HISTORY 



Genus HYLEPHILA Billberg 
Hylephila Billb., Enum. Ins. 81, 1820. Type PapUio pkylaeus 

Drury. 
Euthymus Scud., Syst. Rev. 56, (77), 1872. Type P. pkylaeus 

Drury. 
This genus closely resembles Pamphila in structure but dif- 
fers in the very short antennae and the straighter stigma. The 
female, as in Atalopedes, does not differ much in general struc- 
ture from the male; some are almost indistinguishable from 
campestris, but they never have hyaline spots on the primaries. 
We have but one species of Hylepkila. 



1. HYLEPHILA PHYLAEU8 

Papilio pkylaeus Drury, 111. Ex. Ent. I, 25, pi. xin, ff. 4, 5, 1770 and n, 

app., 1773. 
Phemiades augias Hiibner, (not Linn.), Zutr. exot. Sehmett. n, 10, pi. 531, 

ff. 227, 228, 1821-23. 
Pamphila bucephalus Steph., 111. Brit. Ent. Haust. I, 102, pi. 10, ff. 1, 2, 

1828. 
$ Pamphila hala Butler, Trans. Ent. Soc. London, 1870, 504, (fide G. & 

S.). 
Scudder, Butt. New Eng. n, 1631, 1889. 
Holland, Butterfly Book, 354, pi. xlvii, f. 40, (not brettus$), pi. xlvi, ff. 

18, 19, 1898. 
Wright, Butt. W. Coast pi. xxxi, f. 437 (not hrettus$), 438 $ ,b and c $ 
(not brettoides), 1905. 

Pennsylvania, August; Illinois, April and 
October. Southern United States from Flor- 
ida to Arizona, April to October. Califor- 
nia, June and July. 

Genus ATALOPEDES Scudder 
Atalopedes Scudder, Syst. Rev. 57, 
(78), 1872. Type Hesperia kur- 
ort Edw. 
Pansydia Scud., Syst. Rev. 60, (81), 
1872. Type Hesperia mesogram- 
ma Poey. 
Apiculus of antennae longer than m 
Pampkila, over one-half thickness of 
Fig. 24. Ataiopedes ca^pestHs club in female. Stigma a large, black 
Boisd, a. ciub of^ antenna, b. Pai- blotch, so greatly developed as to 




HESPERIOIDEA OF AMERICA 75 

cause distortion of the posterior margin of the cell so that oppo- 
site the stigma the width of the cell is less than its distance from 
the margin. Base of vein 3 strongly curved; apical angle of 
cell more produced than in Pamphila; vein 7 of secondaries near- 
er to 8 than to end of cell in male. There is much less differ- 
ence in structure between the sexes in this genus than in Pam- 
phila. Pig. 24. 

1. ATAL0PEDE8 CAMPESTRIS 

Hesperia campestris Boisd., Ann. Soc. Ent. France (2), x, 316, 1852. 
$ Hesperia sylvanoides Boisd., Ann. Soc. Ent. France (2), x, 313, 1852. 
Hesperia huron Edw., Proc. Ent. Soc. Phil, n, 16, pi. I, ff, 1, 2, 1863. 
Seudder, Butt. New Eng. n, 1661, 1884. 
Holland, Butterfly Book 352, pi. xlvi, ff, 4, 5, 1898. 
Wright, Butt. W. Coast 245, pi. xxxi, f. 435, 1905. 

Oberthiir, Etudes ix, (1), pi. ccjxl, ff. 2082, $ type; 2085, $ type of syl- 
vanoides, 1905. 
Atlantic to Pacific, Gulf to northern Iowa and Illinois; March to Octo- 
ber. 

The large stigma of the male and the hyaline spots on the primaries of 
the female furnish a convenient means for the identification of this species. 

Genus AUGIADES Hiibner 
Augiades Hbn., Verz. bek. Schmett, 112, 1820. Type Papilio 

sylvanus Esper. 
Ochlodes Scud., Syst. Eev. 57, (78), 1872. Type Hesperia ne- 

morum Boisd. 
Palpi upturned; third joint oblique, very small, without its 
vestiture about one-quarter as long as the second. Apiculus of 
antennae variable but never longer than diameter of club. Costa 
of primaries flattened; outer margin more strongly curved to- 
ward apex; cell about three-fifths as long as wing; vein 5 curv- 
ing slightly toward 4; discocellulars very oblique. Secondaries 
rounded, slightly lobed at anal angle. Stigma straight, moder- 
ately heavy, extending from base of vein 3 to basal two-fifths 
of 1, broken on 2. Mid tibiae weakly spined. Fig. 23. 

I group this rather varied lot of species because of the ex- 
tremely short third joint of their palpi. This is not readily 
seen except when bleached or denuded, but I have carefully ex- 
amined sylvanus, sylvanoides, agricola, and snowi and find that 
they agree, while the others can readily be associated on super- 
ficial resemblance. Other structures are rather variable. 



76 IOWA STUDIES IN NATUKAL HISTOEY 

Key to the species 

1. Spots of primaries shaply defined, often hyaline or subhyaline 2 

Spots more or less ill defined, never hyaline 3 

2. Expanse over one inch ; fulvous spots restricted snowi 

Less than one inch; fulvous of secondaries a diffused discal patch 
milo, agricola 

3. Large; wings pale, tawny, with a little fuscous along the outer mar- 
gin yuma 

Smaller ; wings not broadly tawny 4 

4. Under surface of secondaries with a variably distinct pale transverse 

band ; ground color not pure pale yellowish sylvanoides, napa 

Under surface without a pale band, yellow nemorum, pratincola 

1. AUGIADES SYLVANOIDES 

Hesperia sylvanoides Boisd., Ann. Soe. Ent. France (2), x, 313, 1852. 
$ Hesperia pratincola Boisd., Ann. Soc. Ent. France (2), x, 315, 1852. 
Hesperia agricola Plotz, (not Boisd.), Stett, ent. Zeit. xliv, 219, 1883. 
Hesperia francisca Plbtz, Stett. ent. Zeit. xliv, 220, 1883. 
Wright, Butt. W. Coast 243, pi. xxxi, ff. 430, c, 432, 433, b, c, 1905. 
Oberthur, Etudes ix, (1), pi. ccxl, ff. 2083, 2084, 2089, 1913. 

California, Oregon, Washington, British Columbia; June to August. 

la. race NAPA 
Hesperia napa Edwards, Proe. Ent. Soc. Phil, iv, 202, pi. i, ff. 3, 4, 1864. 

Colorado, August. 

This is practically the same in appearance as sylvanoides but is larger 
and the under surface of the secondaries is less variable. 

2. AUGIADES NEMORUM 

Hesperia nemorum Boisd., Ann. Soc. Ent. France (2), x, 314, 1852. 
PampMla verus Edw., Trans. Am. Ent. Soe. ix, 4, 1881. 
Wright, Butt. W. Coast, pi. xxxi, ff. 430b, 431, 431c?, 1905. 
Oberthur, Etudes ix, (1), pi. ccxl, f. 2086, 1913 (type). 

California, June. 

2a. race PBATINCOLA 
Hesperia pratincola Boisd., Ann. Soc. Ent. France (2), x, 315, 1852. 
Oberthur, Etudes ix, (1), pi. coxl, f. 2088, 1913 (type). 

I follow Barnes and MeDunnough's Check List in placing this form. 
The insect is not represented in the Barnes collection, but Oberthur 's ex- 
cellent figure looks like a specimen of nemorum with the fuscous marginal 
areas of the upper surface greatly reduced. 

3. AUGIADES AGRICOLA 

Hesperia agricola Boisd., Ann. Soc. Ent. France (2), x, 314, 1852. 
Hesperia yrelca Edw., Proc. Ent. Soc. Phil, vi, 207, 1866. 
Pamphila milo Edw., Can. Ent. xv, 34, 1883. 



HESPERIOIDEA OF AMERICA 77 

Pamphila nemorum Skinner (not Boisd.), Ent. News xi, pi. n, f. 21, 1900. 

Kellogg, Am. Ins. pi. ix, f. 21, 1904. 

Oberthur, Etudes ix, (1), pi. coxl, f. 2087, 1913 (type). 

California, May to July. 

Edward's description states that milo has hyaline spots in the primaries 
and agricola none; Oberthur 's figure proves that they are present in the 
type of agricola, hence milo is probably merely a synonym. 

4. AUGIADES SNOWI 

Pamphila snom Edw., Can. Ent. ix, 29, 1877. 
Holland, Butterfly Book 350, pi. xlvii, ff. 29, 30, 1898. 
Biol. Cent.-Am., Rhop. II, 483, pi, 93, ff. 19-23, 1900. 
Arizona and Colorado, June and July. 

5. AUGIADES YUMA 

Hesperia yuma Edw., Trans. Am. Ent. Soc. iv, 346, 1873. 
Pamphila scudderi Skinner, Ent. News x, 111, 1899. 
Skinner, Ent. News xi, pi. II, ff. 9, 10, 1900. 
California, June. Utah and Arizona, July. 

Genus POLITES Scudder 
Polites Scud., Syst. Rev. 57, (78), 1872. Type Hesperia peckius 

Kirby. 
Hedone Scud., op. cit. 58, (79), Type Hesperia brettus Bd. & 

Lee. 
Limoehores Scud., op. cit. 59, (80). Type Hesperia manataaqua 

Scud. 
Pyrrhosidia Scud., Mem. Bost. Soc. Nat. Hist, n, 346, 1874. 

Type Hesperia mysUo Edw. 
Palpi upturned ; third joint about one-half as long as second, 
slender, distinct. Antennae shorter than in Augiades, varying 
from two-fifths as long as the primaries in some females to one- 
half in some males; club rather large, usually longer in the 
female and occasionally almost as long as the shaft; apiculus 
abruptly constricted and reflexed, shorter than thickness of club 
though variable in length. Wings variable; costa of primaries 
usually straight except at base and apex but sometimes slightly 
emarginate or convex; outer margin very slightly sinuate to 
evenly rounded, more rounded in the female. Primaries often 
apically produced in the male, less so in the female. Second- 
aries broadly rounded, very slightly lobed at the anal angle. 
Cell of primaries about three-fifths as long as wing ; vein 5 much 



IOWA STUDIES IN NATURAL HISTORY 



nearer to 4 than to 6 at base ; 2 always arising nearer to 3 than 
to base of wing but variable ; discoeellulars moderately oblique. 

Mid tibiae with promi- 
nent spines. Stigma of 
male in its most com- 
plex form made up of 
an outer oblique black 
line, a black dash from 
end of cell to vein 2 
and a black spot above 
the basal third of vein 
1, the enclosed space 
filled with gray scales, 
and the entire stigma 
followed by a patch of 
raised gray scales. In 
many of the species the 
stigma is much sim- 
pler. Fig. 25. 

I believe that the ac- 
tion of Barnes and Mc- 
Dunnough with refer- 
ence to this group of 
species ( Contributions 
in, 130) is the best 
possible treatment. It 
may be possible to split 
>ff Limochores but I 
find such a complete 
transition in the structures that I hesitate to do so. I place verna 
here because its relation to manataaqua seems to me much closer 
than with the species of Atrytonopsis, where Barnes and McDun- 
nough place it. The gentitalia of the male are closer to dev a, but 
those of the two genera are of a very similar type. The apiculus 
of the antennae is usually longer than in Polites, but I have found 
it variable, and in some specimens fairly short. 

Key to the species 
1. Under surface of secondaries immaculate or with a transverse band of 
pale spots, never sharply bent opposite cell nor with spot at this point 

much the largest 2 

Secondaries otherwise below 7 




Fig. 25. Polites. Antennal clubs: a. verna, b. man- 
ataaqua $ , c. manataaqua Q . Palpi : d. verna, e. 
verna, denuded, dorsal aspect, f. manataaqua, g. 
brettus, denuded. Neuration and details : h. peckius £ , 
i. Posterior margin of cell of primaries of peckius , 
j. Same, taumas fi , k. Same, mystic £> , 1. Same, 
sonora £ , m. Same, manataaqua Q , n. Middle leg 
of verna 



HESPERIOIDEA OF AMERICA 79 

2. Upper surface of secondaries immaculate or with a few very vague 

spots 3 

Upper surface always with the transverse row of spots, more or less 
suffused; usually with a spot in cell 5 

3. Small Florida species. Stigma of male very small, female usually 
with a few powdery whitish spots on the under surface of the sec- 
ondaries baracoa 

Usually moderate to large. Stigma large. Spots, when present, not 
superficial and powdery, and usually showing slightly on upper sur- 
face 4 

4. Smaller; male stigma with several velvety black areas; female with 
maculation of primaries tinged with fulvous, costa and cell often part- 
ly fulvous cernes 

Larger; stigma of male continuous or broken only on vein 2; macula- 
tion of female pale, whitish, rarely with a little pale fulvous in cell 
manataaqua 

5. Under surface of secondaries powdered with yellowish to green scales; 

macular band slender sonora 

Color straw yellow to brown ; band broader 6 

6. Male stigma slender, broken on vein 2; female usually with much yel- 
low-fulvous above; in western specimens pale below and well marked 

above mystic 

Male stigma with three black areas; female with hazy transverse rows 
of spots on all wings and some fulvous in cell, not extensively marked; 
dark below, powdered with yellow. Western species mar don 

7. Pale areas on under surface extending in pale lines along the veins 

■. sabuleti 

Pale areas at most angulate on veins 8 

8. All spots of macular band large, but not equal, that between 4 and 6 

largest ; color yellow peckius 

Spots small except the one between 4 and 6; color white or whitish 

draco 

Pale area covering entire wing except a few dark patches, not divided 
into separate spots and rarely defined as a band; secondaries sometimes 
entirely yellow below. Female with yellow areas heavily powdered with 
dark scales ; secondaries immaculate above 9 

9. Male stigma very broad stigma 

Male stigma moderate brettvs, chusTca ( ?) 

1. POLITE8 VEBNA 

PampHla verna Edw., Proc. Acad. Nat. Sei. Phil. 1862, 57. 
PampMla pottawattomie Worth., Can. Ent. xn, 50, 1880. 
Scudder, Butt. New Eng. n, 1742, 1889. 
Holland, Butterfly Book 360, pi. xlvi, f. 32, 1898. 
Eastern United States, west to Colorado, July. 



80 IOWA STUDIES IN NATURAL HISTORY 

2. POLITES MANATAAQUA 

Hesperia cernes Harris, (not Boisd.), Ins. Inj. Veg., 3rd ed., 316, 1862. 
Hesperia manataaqua Scudder, Proc. Ess. Inst, in, 175, 1863. 
Scudder, Butt. New Eng. n, 1720, 1889. 
Holland, Butterfly Book 357, pi. xlvi, f. 30, 1898. 

Northeastern United States west into Nebraska and South Dakota; June 
and July. 

Holland's figure looks like a dark female of taumas. Manataaqua is 
readily distinguished from taumas in the female sex by its darker color, 
paler maculation and larger size, though the difference is difficult to explain 
in a key. 

2a. race BHENA 
Pamphila rhena Edw., Field and Forest in, 115, 1878. 
Pamphila alcina Skinner, Ent. News iv, 212, 1893. 
Skinner, Ent. News XI, 414, pi. n, f. 25, 1900 (type of alcina). 
Kellogg, Am. Ins. pi. ix, f. 25, 1904 (type of alcina). 

Although retained for many years as a species this is apparently only the 
western race of manataaqua. It is distinguished from the typical form by 
its paler color, more extensive markings and the larger amount of pale 
tawny or yellow fulvous which marks the upper surface. Colorado. 

3. POLITES TAUMAS 

Papilio taumas Fab., Mant. Ins. n, 84, 1787. 

Hesperia thaumas Fab. (not Hufn.), Ent. Syst. m, (i), 327, 1793. 

Hesperia phodon Fab., Ent. Syst., Supp. 431, 1798. 

Hesperia cernes Bd. & Lee, Lep. Am. Sept. pi. 76, ff. 1, 2, 1833. 

Hesperia ahaton Harris, Ins. Inj. Veg. 3rd ed., 317, f. 140, 1862. 

Butler, Cat. Fab. Diurn. Lep. B. M., 277, pi. 2, f. 14; pi. 3, f. 9, 1869. 

Scudder, Butt. New Eng. n, 1725, 1889. 

Holland, Butterfly Book 357, pi. xlvii, f. 20, 1898. 

United States and Canada, April to August. 

I see no reason to doubt that Fabric^s' name applies to this species. 

4. POLITES BABACOA 

Hesperia haracoa Lucas, Sagra's Hist. Cuba vn, 650, 1857. 
Pamphila amadis H.-S., Corr.-Blatt Regensb. xvn, 142, 1863. 
Pamphila myus French, Can. Ent. xvn, 33, 1885. 

Florida, February to April, July, September. I have seen one record of 
its occurrence at Toronto, Canada (A List of Butterflies taken at Toronto, 
Gibson, Ont. Nat. Sci. Bull. No. 6, 1910, 35-44. Baracoa det. Skinner) but 
the only specimens which I have seen came from Florida. 

The species is smaller and darker than taumas and the males are easily 
distinguished by the small stigma. Some females of taumas run very 
close, but in most specimens of baracoa the powdery spots mentioned in 
the key are present. 



HESPERIOIDEA OF AMERICA 81 

5. POLITES MARDON 

Pamphila mardon Edw., Papilio i, 47, 1881. 
Holland, Butterfly Book 354, pi. xlvii, f. 26, 1898. 
Washington, Oregon. 

6. POLITES PECKIUS 

Hesperia peckius Kirby, Faun. Bor. Am. iv, 300, pi. 4, ff. 2, 3, 1837. 
Hesperia wamsutta Harris, Ins. Inj. Veg. 3rd ed., 318, f. 141, 1862. 
Scudder, Butt. New Eng. n, 1683, 1889. 
Holland, Butterfly Book, 353, pi. xlvii, ff. 24, 25, 1898. 

Atlantic coast to Texas and Arizona, southern Canada; May to July. 

It requires more imagination than I possess to see peckius in Cramer's 
figure of coras. 

7. POLITES SABULETI 

Hesperia sdbuleti Boisd., Ann. Soc. France (2), x, 316, 1852. 
Hesperia genoa Plotz, Stett. ent. Zeit. xi>rv, 207, 1883. 
Wright, Butt. W. Coast 246, pi. xxxi, 440, 1905. 
Oberthur, Etudes ix, (1), pi. cdxi,, ff. 2091, 2092, 1913. 

California, April, July to September. 

The pale marks of the lower surfaee are yellowish on a background of 
darker yellowish color. 

7a. race TECUMSEH 
Pamphila sdbuleti, var. tecumseh Grinnell, Ent. News xrv, 11, 1903. 
Pamphila cMspa Wright, Butt. W. Coast 247, pi. xxxi, f. 441, 1905. 

California, June to August. 

Tecwmseh is smaller than typical sdbuleti and has the fulvous areas of 
the upper surface more restricted. The under surface has a greenish-gray 
tone and the pale spots are smaller. 

8. POLITES DRACO 

Pamphila draco Edw., Trans. Am. Ent. Soc in, 274, 1871. 
Skinner, Ent. News xi, pi. n, f. 23, 1900. 
Kellogg, Am. Ins. pi. ix, f . 23, 1904. 

California, Utah and Colorado, June to August. 

9. POLITES SONORA 

Ochlodes sonora Scud., Syst. Rev. 57, (78), 1872. 

PampMla siris Edw., Papilio i, 47, 1881. 

Pamphila sylvanoides Skinner, Syn. Cat. N. Am. Rhop. 84, 1898. 

Wright, Butt. W. Coast 242, pi. xxxi, f. 425, 426 (not Columbia), 1905. 

Washington, Oregon, California; May, June, July and August. 

The only difference which I can see between this and Skinner's variety 
in the series in the Barnes collection is the more yellow color of the under 
surface of its secondaries. 



82 IOWA STUDIES IN NATURAL HISTORY 

9a. race UTAHENSIS 
Pamphila sylvanoides, subsp. utahensis Skinner, Ent. News xxn, 413, 1911. 

Idaho, Wyoming, Colorado and Utah; July and August. 

I would apply this name to the specimens of sylvanoides which are green 
below. 

10. POLITES MYSTIC 

Hesperia mystic Scud., Proc. Ess. Inst, m, 172, 1863. 
Holland, Butterfly Book 351, pi. xlvi, ff. 22, 23, 1898, 

New Jersey, north into Canada and west beyond the Missouri Biver; 
May to July. 

Most specimens from the western limits of the range are of the race 
dacotah, but I have typical mystic from Sioux City, Iowa. In this form 
the under surface of the secondaries is fairly dark with a contrasting pale 
band. 

10a. race DACOTAH 
Hesperia dacotah Edw., Trans. Am. Ent. Soc. in, 277, 1871. 
Pamphila mystic, subsp. pallida Skinner, Ent. News xxn, 412, 1911. 

Colorado, June; eastward into Iowa. South Dakota. 

The under surface of the secondaries is yellow, scarcely darker than the 
pale transverse band in extreme specimens. 

ab. WEETAMOO 
Thymelicus mystic weetamoo Scudder, Butt. New Eng. n, 1707, 1889. 

A dark brown melanic aberration occurring in the female sex. Ordinary 
maculation much reduced, of separate spots. 

ao. NUBS 
Thymelicus mystic nubs Scudder, Butt. New Eng. n, 1707, 1889. 
Also a female aberration; dark areas suffused with tawny scales. 

11. POLITES BRETTUS 

Hesperia brettus Boisd. & Lee., Lep. Am. Sept. pi. 75, ff. 3-5, 1833. 

Hesperia wingina Scud., Proc. Ess. Inst, in, 173, 1863. 

Hesperia unna Plotz, Stett. ent. Zeit. xliv, 204, 1883. 

Scudder, Butt. New Eng. n, 1701, 1889. 

Holland, Butterfly Book 351, pi. xlvii, f. 41, 1898. 

Gibson, Ont. Nat. Sci. Bull. No. 6, 42, 1910. 

Florida, north to Virginia, west to Texas; April, July, August and Octo- 
ber. Gibson lists one specimen from Toronto, Canada, determined by Dr» 
Skinner. 

11a. race BBETTOIDES 
Pamphila brettoides Edw., Papilio in, 71, 1883. 

Western Texas and Arizona. 

Brettoides has very narrow dark outer margins on the upper surface in 
the male, with no more than a trace of the patch at the end of the stigma; 
the under surface is likewise broadly tawny yellow. I do not know the 
female. 



HESPERIOIDEA OF AMERICA 83 

12. POLITES STIGMA 

Pamphila stigma Skinner, Can. Ent. xxvm, 188, 1896. 
Skinner, Ent. News xi, pi. n, f. 15, 16, 1900 (15 Cotype). 
Kellogg, Am. Ins. pi. ix, ff. 15, 16, 1904 (15 Cotype). 

Texas, New Mexico. 

I have seen the type of stigma in the Strecker collection, and it is sim- 
ilar to brettus but dark, heavily marked above, and has a very large stigma. 
Vibex is intermediate between it and brettus but at present I am not pre- 
pared to agree with Dyar's suggestion that they are all the same species 
(Jn. N. Y. Ent. Soc. xm, 128, 1905). Godman and Salvin make stigma 
synonymous with vibex (Biol. Cent.-Am., Rhop. II, 480, 1900). 

13. POLITES CHUSKA 

Eesperia clmsTca Edw., Trans. Am. Ent. Soc. iv, 346, 1873. 

I know nothing of this species. It is placed between sabuleti and draco 
in Barnes and McDunnough 's Check List, but this was done merely with 
a knowledge of the description. The type locality is Arizona. 

Genus CATIA Godman & Salvin 

Catia G. & S., Biol. Cent.-Am., Rhop. n, 481, 1900. Type Hes- 
peria drwryi Latreille. 

Catia is structurally similar to Polites 
but differs in the long slender apiculus 
of! the antennae, which always exceeds 
the diameter of the club, and in the form 
of the male stigma. The stigma is com- 
posed of a velvety black patch below the 
end of the cell and a similar patch above 
the inner third of the anal vein, with Fig. 26. cam otho a. & s. a. 
large, silky, gray scales between. In the Club of antennae ' b ' Neuration 
bleached wing it appears as two similar oval spots, one on each 
side of vein 1. Fig. 26. 

In describing Catia Godman and Salvin say of the peculiar 
structure of the stigma that it "is so remarkable that we think 
it of sufficient importance to put the species possessing this char- 
acter into a separate genus." Otho is closely related to the 
species now included in Polites and was formerly associated with 
some of them in Thymelietis, but the form of the apiculus sep- 
arates them, and no fundamental or superficial similarity can 
be traced in the stigmata. 




84 IOWA STUDIES IN NATURAL HISTORY 

1. CATIA OTHO 

Papilio otho A. & S., Lep. Ins. Ga. i, 31, pi. 16, 1797. 

Eesperia drury Latr., Enc. Meth. ix, 767, 1823. 

Thymelicus pustula Geyer, Zutr. exot. Schmett. rv, ff. 625, 626, 1832. 

Eedone aetna Scud, (not Boisd.), Syst. Rev. 58, (79), 1872. 

Scudder, Butt. New Eng. n, 1696, 1889. 

Biol. Cent.-Am., Rhop. n, 482, pi. 93, f. 18, $ gen., 1900. 

Florida and Texas, May and June. 

The southern specimens which I refer to otho tend to a reddish shade 
on the under surface; on the upper surface of the secondaries there are 
some discal spots, while the primaries have fulvous on the basal half of 
the costa, a complete series of subapical spots, and sometimes other ful- 
vous marks in addition to those found in egeremet. 

la. race EGEREMET 
Eesperia egeremet Scud., Proc. Ess. Inst, in, 174, 1863. 
PampMla ursa Worth., Can. Ent. xn, 49, 1880. 
Eesperia cinna Plotz, Stett. ent. Zeit. xliv, 58, 1883. 
Scudder, Butt. New Eng. n, 1696, 1889. 
Holland, Butterfly Book 351, pi. xlvi, ff. 28, 29, 1898. 

United States and southern Canada, west to the Rocky Mountains; July. 
Texas in October. 

Under surface pale fuscous, sometimes tinged with brown; secondaries 
rarely with a trace of discal marks above, and pale spots of primaries lim- 
ited to three or less beyond the stigma and one or two subapical points. 

The females of otho and egeremet have the same pale marks as the males. 



Genus POANES Scudder 
Poanes Scudder, Syst. Rev., 55, (76), 1872. 
^^^ Type Hesperia massasoit Scud. 

^SS^\ Phycanassa Scud., op. cit. 56, (77) . Type Hes- 
peria viator Edw. 
^^rrmg. Paratrytone Dyar, Jn. N. Y. Ent. Soc. xm, 136, 

-^^^c^ 1905. Type Pamphila howardi Skinner. 

Palpi oblique; second joint shaggy, third 

^tf$$\ small, not long though sometimes rendered 

<£^* prominent by its vestiture. Antennae about 

one-half as long as primaries; club large, api- 

culus varying from rather slender and slightly 

shorter than thickness of club to long, thick, 

Fig. 27. Antennai tapering and not well reflexed. Primaries 

&A P SSS2L«; trigonate; costa slightly convex; outer margin 

c. h0})0 ^ ^ e ^ xUe ^ slightly to prominently rounded ; apex rather 



HESPERIOIDEA OF AMERICA 85 

prominent. Secondaries broadly rounded, slightly lobed at anal 
angle. Cell of primaries well over one-half as long as wing ; vein 
5 moderately curved in basal half, arising nearer to 4 than to 6 ; 
2 nearer to 3 than to base of wing. Cell of secondaries less than 
one-half as long as wing. Mid tibiae with a few long spines. 
Fig 27. 

Hobomok, zdbvXon, taxiles, and melane were first placed in 
Poanes by Barnes and McDunnough (Contributions in, 132, 
1916). Although melane is rather anomalous, it apparently 
belongs with the other species, whose relation to massasoit 
through hobomok is obvious. Owing to the great range of varia- 
tion thus introduced into the genus in the structure of the an- 
tennae, palpi, and wings, I have added also viator, which differs 
somewhat in wing form, and the species placed by recent writers 
in Paratrytone. These last possess the stigma in the male but 
it is so variable that I regard it as in the process of development. 
In howardi, aaroni, and streokeri it is very slender, sometimes 
scarcely visible but often well marked, and in yehl it is heavier 
but very variable. In one of the types it is slender, while in the 
other it is as heavy as in some specimens of conspicua. Includ- 
ing all of these species Poanes becomes such a complex genus that 
I have drawn up the following diagram to show the apparent 
relations of the several groups: 



howardi 




\ 




aaroni 




\ 

yehl 


streckeri 


\ / 

\ »/ 

\ / 

massasoit 


/ 

hobomok 


\ 

\ 


/ 

zabulon 


\ 
\ 


/ 

taxiles 


\ 

viator 


/ 

melane 





86 IOWA STUDIES IN NATURAL HISTORY 

Key to the species 

1. Under surface of secondaries with bright yellow marks 2 

No clear yellow on under surface 4 

2. Yellow a broad transverse band crossed by a broad ray through cell . . 3 
Yellow much more extensive zabttion 

3. Wings broadly yellow-fulvous with narrow fuscous margins; yellow of 

under surface rather dull taxUes 

Wings less broadly fulvous and more or less fuscous within outer mar- 
gin ; yellow of under surface of secondaries very bright hooomoTc 

Wings dark, with or without small pale spots massasoit 

4. Upper surface of secondaries with pale markings indefinite, or faint; 

sometimes immaculate 5 

This surface with a bright yellow-fulvous patch 8 

5. Pale spot in cell of primaries at least faintly indicated. . . .pocahontas 
No trace of this spot 6 

6. Wings immaculate above massasoit form suffusa 

Wings with pale spots 7 

7. Under surface with some bluish irroration zdbulon $ 

Without bluish irroration melane 

8. Primaries with definite spots or a dark stigma 9 

Spots diffuse, extended, or discal area broadly yellow-fulvous; male 
stigma pale, slender 10 

9. $ with stigma; $ with three small, round, pale spots on under surface 

of secondaries yeM 

$ without stigma; 9 without such spots viator 

10. Under surface of secondaries with a vague, pale dash through cell 

howardi, aaroni 

Under surface partly greenish-fuscous with contrasting pale veins 
streckeri 

1. POANE8 VIATOR 

Hesperia viator Edw., Proc. Ent. Soc. Phil, iv, 202, pi. i, f. 5, 1865. 
Scudder, Butt. New Eng. n, 1604, 1889. 
Holland, Butterfly Book 362, pi. xlvi, f . 15, 1898. 

New York, New Jersey, Michigan, Southeastern Canada, Omaha, Neb., 
(Leussler) ; June to August. 

2. POANES MASSASOIT 

Hesperia massasoit Scud., Proc. Ess. Inst, in, 171, 1863. 

Scudder, Butt. New Eng. n, 1597, 1889. 

Holland, Butterfly Book 361, pi. xlvi, ff. 21, 22, 1898. 

New Jersey, New York, Ehode Island, Iowa, July. Skinner (Cat. p. 80) 
records it westward and southward to Texas and Colorado. 

The male is either immaculate blackish brown above or with a few small 
yellow-fulvous spots, while the female frequently has the spots of large size 
an^ a very pale shade. 



HESPERIOIDEA OF AMERICA 87 

Form SUFFUSA 
Famphila massasoit } var. suffusa Laurent, Ent. News in, 15, 1892. 
Skinner, Ent. News XI, pi. II, f. 22, 1900. 
Kellogg, Am. Ins. pi. ix, f . 22, 1904. 

New Jersey, New York; June and July. 

The pale area of the under surface of the secondaries of this form is 
heavily powdered with rusty brown scales. 

3. POANES HOBOMOK 

Eesperia hobomdk Harris, Ins. Inj. Veg. 3rd ed., 313, f. 137, 1862. 
Atrytone zabulon Scud., (not Bd. & Lee), Butt. New Eng. n, 1617, 1889. 
Atrytone zabulon Holland (not Bd. & Lee), Butterfly Book 364, pi. xlvii, 
ff. 37, 38, 1898. 
West Virginia north into Canada and west into Nebraska; May and June. 

$ form POCAHONTAS 
Hesperia pocdhontas Scud., Proc. Ess. Inst, ni, 171, 1863. 
Hesperia qvadaquina Scud., Proc. Bost. Soc. Nat. Hist, xi, 381, 1868. 
Scudder, Butt. New Eng., n, 1617, 1889. 
Skinner, Ent. News xi, pi. n, ff. 3, 4, 1900 (not normal hobomdk $). 

Northeastern United States, Quebec; June. 

Pocahontas differs from the normal female in the pale shade and greater 
restriction of the spots on the upper surface, and the brown powdering of 
the secondaries below. 

4. POANES ZABULON 

Hesperia zabulon Boisd. & Lee, Lep. Am. Sept. pi. 76, ff. 6, 7, 1833. 
Hesperia zabulon, form pocdhontas Holland (not Scudder), Butterfly Book 
364, pi. xlvii, f. 39, 1898. 

Illinois, Pennsylvania, Kentucky, North Carolina; May and August. 

Holland's figure looks much more like the true female of zabulon than 
like pocdhontas, though it is impossible to identify a figure of the upper 
surface accurately. The under surface of the secondaries of the male of 
zabulon is bright yellow with a few marks of brown. In the female the 
brown areas are more extensive and the entire wing is so heavily powdered 
with rusty scales that it is difficult to trace the pale areas at all. 

5. POANES TAXILES 

Pamphtta taxiles Edwards, Trans. Am. Ent. Soc. ix, 5, 1881. 
Holland, Butterfly Book 365, pi. xlvii, ff. 31, 32, 1898. 
Colorado and Arizona, June and July. Nevada, N. M. 

6. POANES MELANE 

Hesperia melane Edw., Trans. Am. Ent. Soc. n, 312, 1869. 
Biol. Cent.-Am., Rhop. II, 494, pi. 94, ff. 30-34, 1900. 
Holland, Butterfly Book 365, pi. xlvi, ff. 7, 8, 1898. 
Wright, Butt. W. Coast 249, pi. xxxi, f. 453, 1905. 



88 IOWA STUDIES IN NATURAL HISTORY 

California, south into Mexico; May. 

Melane and the female of taxiles are similar but they are not difficult to 
separate; usually the locality from which the specimens come is sufficient. 

7. POANES HOWARDI 
Pamphila howardi Skinner, Can. Ent. xxvin, 187, 1896. 
Phycanassa viator Holland, (not Edwards), Butterfly Book pi. xlvi, f. 14, 
1898. Op. cit. pi. xlvi, f. 38. 
Florida. 

The expanse of specimens which I have seen runs between thirty-two and 
thirty-six millimeters. Aside from this and its darker color the species 
does not differ superficially from aaroni. 

8. POANES AARONI 

Pamphila aaroni Skinner, Ent. News I, 6, 1890. 
Holland, Butterfly Book 363, pi. xlvi, f. 37, 1898. 

New Jersey, June and August. I have seen specimens only from Angle- 
sea and Atlantic City. 

Aaroni expands twenty-seven to thirty-three millimeters and is paler, 
more yellowish, than howardi. Howardi may yet prove to be a southern 
race of aaroni. 

9. POANES YEHL 

Pamphila yehl Skinner, Ent. News iv, 212, 1893. 
Holland, Butterfly Book 359, pi. xlvi, f. 40, 1898. 

Tennessee, Georgia, Mississippi; August and September. 

Superficially this species looks more like a relative of A. conspicua but 
the mid tibiae are spined. The white spots on the under surface of the 
secondaries in the female are unique. 

10. POANES RADIANS 

Hesperia radians Lucas, Sagra's Hist. Cuba vn, 650, 1857. 
Pamphila streckeri Skinner, Ent. News iv, 211, 1893. 
Skinner, Ent. News xxviii, 82, 1917. 

Florida. 

The only specimen which I have seen is the type of streckeri and since 
it lacks the middle legs it is impossible to place the species definitely. 
Barnes and McDunnough place it in the genus Euphyes in the check list, 
but without specimens at hand. Its superficial resemblance is rather with 
aaroni. 

Genus ATRYTONE Scudder 

Atrytone Scud., Syst. Rev. 56, (77), 1872. Type Hesperia iowa 

Scud. 
Euphyes Scud., Syst. Rev. 59, (80), 1872. Type Hesperia meia- 

comet Harris. 



HESPERIOIDE A OF AMERICA 89 

Anatrytone Dyar, Jn. N. Y. Ent, Soc. xm, 140, 1905. Type 
Hesperia delaware Edwards. 

Palpi upturned; second joint closely appressed, smoothly and 
deeply scaled; third moderate, oblique. Antennae about one- 
half as long as primaries ; club long, moderately thick ; apiculus 
about as long as thickness of club, sometimes a little shorter. 
Costa of primaries flattened or very slightly convex ; outer mar- 
gin moderately and almost evenly rounded; apex usually prom- 
inent. Secondaries rather small, rounded, slightly lobed at anal 
angle; a little more apically elongate in the females. Cell of 
primaries normal; discocellulars oblique, weak; vein 5 curved, 
nearer to 4 than to 6; 2 about intermediate between 3 and base 
of wing. Stigma present or absent, composed of two similar, 
slender, elliptic pieces placed end to end on opposite sides of 
vein 1. Mid tibiae without spines. 

The long antennal club and spineless mid tibiae make this a 
very distinct genus as used here, but no characters are available 
for the separation of Atrytone and Euphyes of other writers 
lexcept the male stigma, which is present only in the species 
formerly placed in Euphyes. The types of the two do not re- 
semble each other, but in the species congeneric with them we 
find an excellent connecting series, in which arpa and hyssus 
differ very slightly except in the stigma. 

Key to the species 

1. Under surface of secondaries immaculate or with a faint, pale, trans- 
verse band on disk 2 

Under surface of secondaries with two pale rays dion 

Under surface with a few diffuse spots forming a curved transverse 
row conspicua 

2. Fringe of inner margin of' secondaries white bvmaouXa 

Fringe of this margin not white 3 

3. Wings immaculate fuscous above and below or with a few small pale 

spots on primaries ($) vestris 

Wings with more pale markings 4 

4. Wings mostly dark brownish-gray below. palatka 

Wings tinged with yellow or red below 5 

5. Stigma present arpa $ 

Stigma absent 6 

6. Upper surface of secondaries fuscous 7 

Secondaries with fulvous discal marks 8 



90 IOWA STUDIES IN NATURAL HISTORY 

7. Primaries with a transverse row of fulvous spots arpa $ 

With diffuse pale fulvous areas arogos $ 

8. Veins black 9 

Veins not black arogos 

9. Wings usually broadly yellow-fulvous with a terminal fuscous band 

above; immaculate yellow or brownish yellow below logan 

Wings with the fulvous definitely limited; under surface of second- 
aries in most specimens with a faint pale transverse band, never clear 
yellow byssus 

1. ATRYTONE AROGOS 

Tapilio vitellius A. & S., (not Fab.), Lep. Ins. Ga. I, 33, pi. xvn, 1797. 
Hesperia arogos Boisd. & Lee, Lep. Am. Sept. pi. 76, ff. 3, 4, 5, 1833. 
Hesperia iowa Scud., Proc. Bost. Soc. Nat. Hist, xi, 401, 1868. 
Hesperia mutms Plotz, Stett. ent. Zeit. xltv, 199, 1883. 
Atrytone vitellius Holland (not Fab.), Butterfly Book 364, pi. xlvi, f. 
6, 1898. 

Florida, August and September. Nebraska and Iowa, June and July. 
Ocean County, N. J., July (Davis). 

The pale tawny wings with their broad, even, fuscous borders distinguish 
the male; the female is readily associated with the male, but the fuscous 
is more extensive, encroaching upon the discal area and often almost oblit- 
erating the tawny color. 

2. ATRYTONE LOGAN . . 

Hesperia logan Edw., Proc. Ent. Soc. Phil, n, 18, pi. I, f. 5, 1863. 

Hesperia delaware Edw., op. cit. p. 19, pi. 5, f. 2. 

Seudder, Butt. New Eng. n, 1614, 1889. 

Biol. Cent.-Am., Ehop. n, 490, pi. 94, ff. 4-6, 1900. 

Holland, Butterfly Book 365, pi. xlvi, f . 24, 25, 1898. 

Florida to Texas, north to Montana and Illinois; July and August. 

2a. race LAGUS 
PampMla lagus Edw., Trans. Am. Ent. Soc ix, 5, 1881. 

I regard this as scarcely worth separating from logan. It is the western 
race, and in extreme forms has the fuscous terminal borders reduced to 
very slender lines and the under surface very pale. 

3. ATRYTONE BYSSUS 

? Hesperia bulenta Bd. & Lee, Lep. Am. Sept. pi. 67, ff. 1-5, 1833. 
PampMla byssus Edw., Can. Ent. xn, 224, 1880. 
Holland, Butterfly Book 358, pi. xlvi, f. 20, 1898. 

Florida, August. Skinner includes Texas (Cat. p. 89). 

Br. MeBunnough, places bulenta tentatively as a synonym of byssus. 
The figure is a striking thing, unlike any known species of North America, 
but it does bear a remote resemblance to this species. 



HESPERIOIDEA OF AMERICA 91 

4. ATRYTONE ARPA 

Eesperia arpa Boisd. & Lee, Lep. Am. Sept. pi. 68, 1833. 

Florida, June, September and October. 

The stigma is present in the males of this and all of the following 
species, which make up the former genus Euphyes. 

5. ATRYTONE PALATKA 

Eesperia palatlca Edw., Trans. Am. Ent. Soc. I, 287, 1867. 
Eesperia floridensis Plotz, Stett. ent. Zeit. xliv, 196, 1883. 
Scudder, Butt. New Eng. in, 1863, 1889. 
Holland, Butterfly Book 358, pi. xlvi, f. 21, 1898. 

Florida, May, August to October. Skinner gives its range as "Gulf 
States, Neb." (Cat. p. 89). 

In the original description the name of this species was spelled pilaika 
but this was amended by Edwards himself in his later writings. It is the 
largest species of the genus. 

6. ATRYTONE DION 

PampMla dion Edw., Can. Ent. xi, 238, 1879. 

New York, Ohio, Wisconsin, Michigan, Illinois and Omaha, Neb. (Leuss- 
ler) ; June and July. St. Louis, Mo. (Knetzger). 

The pale dashes on the under surface of the secondaries are unique in 
this genus. 

7. ATRYTONE CONSPICUA 

Hesperia conspicua Edw., Proc. Ent. Soc. Phil, n, 17, pi. 5, f . 5, 1863. 
$ Eesperia pontiac Edw., op. eit. 17, pi. xi, f. 5. 
Eedone orono Scud., Syst. Rev. 58, (79) 1872. 
Scudder, Butt. New Eng. n, 1732, 1889. 
Holland, Butterfly Book 358, pi. xlvi, ff. 16, 17, 1898. 
New Jersey north to Massachusetts and west into Nebraska; July. 

8. ATRYTONE BIMACVLA 

Eesperia Mmacula G. & R., Ann. Lye. Nat„ Hist. N. Y. vm, 433, 1867. 
Eesperia acanootus Scud., Proc Bost. Soc. Nat. Hist, xi, 381, 1868. 
Eesperia illinois Dodge, Can. Ent. rv, 217, 1872. 
Scudder, Butt. New Eng. n, 1718, 1889. 

Ontario, New Jersey, New York, Iowa; July. Skinner lists Nebraska 
(Cat. p. 88). I have taken one specimen at Sioux City, Iowa. 

The under surface of the secondaries is usually pale with the veins 
marked in white. The upper surface has a little yellow-fulvous on each 
side of the stigma in the male, and only two or three small, extradiseal 
spots in the female which are of a very pale color. 

9. ATRYTONE VESTRIS 

Eesperia vestris Boisd., Ann. Soc. Ent. France (2), x, 317, 1852. 
Eesperia metacomet Harris, Ins. Inj. Veg. 3rd ed., 317, 1862. 



92 



IOWA STUDIES IN NATURAL HISTORY 



Pamphila rurea Edw., Proc. Acad. Nat. Sci. Phil. 1862, 58. 
Hesperia Mowah Reakirt, Proe. Ent. Soc. Phil, vi, 150, 1866. 
Hesperia osyJca Edw., Trans. Am. Ent. Soe. I, 288, 1867. 
Pamphila osceola Lint., 30th Rep. N. Y. Mus. Nat. Hist. 170, 1878. 
Scudder, Butt. New Eng. n, 1739 and m, 1865, 1889. 
Holland, Butterfly Book 360, pi. xlvi, f. 31, 1898. 
Wright, Butt. W. Coast 247, pi. xxxi, f. 442, 1905. 
ObertMr, Etudes ix, (1), pi. ccxl, f. 2093, 1913 (type). 
United States and Southern Canada; May to July. 

9 form IMMACULATUS 
Pamphila vestris, var. immaculatus Williams, Ent. News xxv, 267, 1914. 

Described from the Jemez Mts., New Mexico. I have seen it from the 
White Mts., Arizona, but not from more northern localities. As the name 
implies, it lacks the whitish spots usually found on the primaries of the 
female. 

Genus ATRYTONOPSIS Godman & Salvin 
Atrytonopsis G. & S., Biol. Cent.-Am., Rhop. n, 497, 1900. Type 
Hesperia deva Edw. 

Palpi upturned ; 
third joint moderate, 
oblique, not concealed 
in vestiture of second. 
Antennae slightly less 
than one-half as long 
as primaries ; club 
moderate, longer in 
female than male ; 
apiculus shorter than 
thickness of club in 
male, equal to it or 
longer in female. Pri- 
maries of male apic- 
ally produced; costa 
nearly straight; outer margin slightly rounded; apex rounded- 
acute. Secondaries rounded; outer margin flattened at end of 
cell; anal angle slightly lobed; length from humeral angle to 
anal angle greater than through cell in male and less in female. 
Cell of primaries three-fifths as long as wing; vein 5 curved at 
base, nearer to vein 4 than to 6; L. D. C. almost transversa; 
M. D. C. scarcely visible, very oblique; vein 2 almost inter- 










Fig. 28. Antennal clubs: a. Atrytonopsis deva Edw., 
b. A pitiacus Edw., c. A. edivardsi B. & McD., f. 
Oligoria maculata Edw. h. Lerodea eufaia Edw., Pal- 
pi, d. A. deva Edw., g. Maxtor bellus Edw., i. Le- 
rodea eufaia Edw., e. Detail of neuration : end of cell 
of primaries, Lerema accius S. & A. 



HESPERIOIDEA OF AMERICA 93 

mediate between 3 and base of cell. Stigma rudimentary, con- 
sisting of a few modified scales faintly indicating the position 
of the structure ; well developed in a few species, where it is sim- 
ilar to that of Atrytone but more slender. Mid tibiae spiny. 
Pig. 28. 

The absence of yellow-fulvous, frequent occurrence of gray 
scales on the under surface of the wings, and the acute apices of 
the primaries in the males of most of the species give this genus 
a very distinctive habitus. 

Key to the species 

1. Fringes not checkered 2 

Fringes checkered 7 

2. Under surface of secondaries with a transverse row and three subasal 

white spots ; not heavily gray-powdered loammi 

Spots partly obsolete or hyaline 3 

3. Secondaries with hyaline spots pittacus 

Secondaries without hyaline spots 4 

4. Fringes of secondaries white or whitish 5 

Fringes concolorous with wings or slightly paler 6 

5. Fringes dirty white, usually dark at anal angle lunus 

Fringes pure white, rarely intermixed with dark scales, usually not 
very dark at anal angle deva 

6. Wings very dark Manna 

Wings pale vierecki 

7. Under surface marbled with purplish ; spots semi-hyaline cestus 

Under surface heavily gray powdered 8 

8. Spots yellowish, opaque or nearly so python 

Spots white, subhyaline edwardsi 

1. ATRYTONOPSIS LOAMMI 

Lerema loammi Whitney, Can. Ent. vin, 76, 1876. 
Pamphila regvXus Edw., Trans. Am. Ent. Soe. ix, 5, 1881. 
Skinner, Ent. News xi, pi. n, f. 24, 1900. 
Kellogg, Am. Ins. pi. ix, f. 24, 1904. 

Florida, March and October. North Carolina, July. 

The dark brown ground color and the pure white, opaque spots on the 
under surface of the secondaries separate loammi readily from the rest 
of the genus. 

2. ATRYTONOPSIS HIANNA 

Hesperia hianna Scudder, Proc. Bost. Soe. Nat. Hist, xi, 382, 1868. 

Hesperia grotei Plbtz, Stett, ent. Zeit. xuv, 54, 1883. 

Scudder, Butt. New Eng. n, 1771, 1889. 

Holland, Butterfly Book, 366, pi. xlvi, ff. 9, 10, 1898. 

Northeastern United States westward into Nebraska, Manitoba; June. 



94 IOWA STUDIES IN NATURAL HISTORY 

3. ATRYTONOPSIS LVNV8 

Pamphila lunus Edwards, Papilio iv, 56, 1884, 

Arizona, June to August. 

Similar to deva but larger and darker, and with the white areas not so 
pure as in deva. 

4. ATRYTONOPSIS DEVA 

Besperia deva Edw., Trans. Am. Ent. Soe. v, 292, 1876. 
Biol. Cent. -Am., Rhop. n, 498, pi. 95, ff. 6-10, 1900. 

Arizona and Utah. Skinner lists southern Colorado (Cat. p. 87). 

5. ATRYTONOPSIS VIERECKI 

Pamphila vierecki Skinner, Ent. News xm, 213, 1902. 

Ft. Wingate, New Mexico, June; two males, one compared with the 
type, in the Barnes collection are all that I have seen. 

Vierecki is similar to deva but smaller, paler and more grayish, with 
two spots in the end of the cell of the primaries, sometimes connected, and 
a well marked stigma in the male. 

6. ATRYTONOPSIS PITTACVS 

Pamphila pittacus Edw., Papilio n, 138, 1882. 

Biol. Cent.-Am., Ehop. n, 49S, pi. 95, ff. 11-13, and 14, 15 (not python 

Edw.), 1900. 
Skinner, Ent. News XI, pi. n, ff. 17, 18, 1900. 
Kellogg, Am. Ins. pi. ix, ff. 17, 18, 1904. 

Arizona, July. 

The straight row of hyaline spots on the secondaries characterizes pitta- 
cus among our species. 

7. ATRYTONOPSIS PYTHON (Plate I, Fig. 1) 
Pamphila python Edw., Papilio n, 139, 1882. 
Arizona, May and June. 

Python is the only one of our species in which the spots are distinctly 
yellowish. 

7a. race MABGABITA 
Pamphila margarita Skinner, Can. Ent. xlv, 426, 1913. 
Described from Jemez Springs, New Mexico. 
I am not familiar with this form. 

8. ATRYTONOPSIS CESTUS 
Pamphila cestus Edw., Papilio rv, 57, 1884. 

Southern Arizona. I am not familiar with this species. 

9. ATRYTONOPSIS EDWARDSI 

Atrytonopsis edwardsi B. & McD., Contributions in, (2), 135, pi. vm, ff. 
9, 10, 1916. 



HESPERIOIDEA OF AMERICA 95 

Pamphila cestus Wright, (not Edw.), Butt. W. Coast 249, pi. xxxn, f. 
482, 1905. 

Arizona. 

This species was described to correct a common misconception of cestus 
and the types are undoubtedly distinct from the species on which the de- 
scription of cestus was based. I believe that the name will fall before 
Hesperia ovmia Hew., illustrated in the Biologia (PI. 97, ff. 1, 2, 1900) un- 
der the name Thespieus ovinia. The type of ovmia in the British Museum 
will have to be examined to settle the matter definitely, but even from the 
figures it is easy to see that the species can hardly belong in Thespieus. 

Genus OLIGORIA Scudder 
Oligoria Scud., Syst. Rev. 61, (82), 1872. Type Hesperia ma- 
culata Edw. 

Structure not much different from Atrytonopsis. Male pri- 
maries less apically prolonged and without stigma. Vein 5 near- 
er to 4 than in the preceding genus. Middle tibiae with a few 
long spines. Apiculus of antennae abruptly constricted, sharp- 
ly reflexed, very slender and usually about twice as long as 
thickness of club. 

Dyar remarks (Jn. N. Y. Ent, Soc. xm, 137, 1905) that he 
is unable to separate this genus from Lerodea and therefore 
places maculata in the latter. He is followed in this by Barnes 
and McDunnough in the Check List, but the differences between 
maculata and eufala are so striking that they must be separated. 
Since maculata agrees with no other genus known to me, I retain 
Oligoria for the one species. Fig. 28. 

1. OLIGORIA MACULATA 

Hesperia maculata Edw., Proe, Ent. Soc. Phil, iv, 202, pi. i, f. 6, 1865. 
Hesperia norus Plotz, Stett. ent. Zeit. xliv, 36, 1883. 
Scudder, Butt. New Eng. n, 1761, 1883. 
Holland, Butterfly Book 361, pi. xlvi, f. 35, 1898. 

Florida, May to July. Skinner gives its range as the Gulf States and 
occasionally New York. (Cat. p. 87). 

Genus LEREMA Scudder 

Lerema Scud., Syst, Rev. 61, (82), 1872. Type Papilio accius 

A. & S. 

Palpi oblique; third joint moderate, partly concealed by ves- 

titure of second. Antennae about one-half as long as primaries ; 

club moderate; apiculus slender, longer than thickness of club. 



96 IOWA STUDIES IN NATURAL HISTORY 

Primaries rather long; eosta flattened in middle; outer margin 
curved, flattened before anal angle; apex rounded-rectangular. 
Secondaries lobed slightly at anal angle, otherwise rounded. Cell 
of primaries over three-fifths as long as wing ; discocellulars weak, 
slightly oblique ; vein 5 arising a little nearer to 4 than to 6, al- 
most straight. Male with a slender, well developed stigma run- 
ning from the base of vein 3 to just within the middle of vein 1. 
Middle tibiae with a few long spines. Fig. 28. 

1. LEBEMA ACCIUS 

Papilio accws A. & S., Lep. Ins. Ga. I, 45, pi. 23, 1797. 

Eesperia monoco Scud., Proc. Ess. Inst, in, 178, 1863. 

Hesperia punctella G. & E., Trans. Am. Ent. Soc. i, 1, 1867. 

Hesperia nortonii Edw., Trans. Am. Ent. Soc. I, 287, 1867. 

Scudder, Butt. New Eng. n, 1768, 1889. 

Holland, Butterfly Book 366, pi. xlviii, f. 8, 1898. 

Biol. Cent.-Am., Rhop. n, 554, pi. 99, f. 44, 1900. 

Southern half of United States east of Rockies; May, July, August, Octo- 
ber, November. Skinner (Cat. p. 87) mentions a record by Aaron from 
Eastern Pennsylvania. 

Genus EPIPHYES Dyar 
Epiphyes Dyar, Jn. N. Y. Ent, Soe. xm, 132, 1905. Type 
Pamphila Carolina Skinner. 
I have seen but one poor specimen of the female of Carolina. 
Prom it nothing can be told except that vein 5 is but slightly 
curved and not much nearer to 4 than to 6. It therefore belongs 
with Lerema and allied genera, and according to Dyar's descrip- 
tion of the male stigma it should constitute a good genus. The 
original description of Epiphyes is as follows: "Antennal club 
cylindrical, the point rather obtuse and about equal to the diam- 
eter of the club. Palpi with the third joint moderate, rather 
slender ; wings normal, vein 2 arising at the middle of the cell, 
3 before the end. Mid tibiae spiny. Male stigma a large, ill 
denned blotch. Type Pamphila Carolina Skinner. ' ' 

1. EPIPHYES CAROLINA 

Pamphila Carolina Skinner, Ent. News in, 222, 1892. 
Holland, Butterfly Book 367, pi. xlvi, f. 36, 1898 (type). 

North Carolina. 

The species is easily recognized by the well defined, pale yellow macula- 
tion and the form of vein 5 of the primaries. 



HESPERIOIDEA OF AMERICA 97 

Genus MASTOR Godman & Salvin 
Mastor G. & S., Biol. Cent.-Am., Rhop. n, 567, 1900. Type Mas- 
tor anubis G. & S. 
? Megistias G. & S., op. cit. 571. Type Hesperia tripunctata 
Latr. 

Palpi upturned; third joint small. Antennae slightly more 
than one-half as long as primaries in male, less in female ; apicu- 
lus shorter than thickness of club and variously reflexed; club 
short, rather stout. Costa of primaries flattened; outer margin 
slightly rounded ; apex somewhat produced. Secondaries broad- 
ly rounded, relatively small ; in the female the primaries are less 
produced and the apex of the secondaries more prominent than 
in the male, much as in Atrytme. The male possesses a small 
stigma made up of a dot of scales below vein 2 and a longer 
patch above, variably developed in different specimens. It is 
much larger in bellus than in phylace, very small in oslari and 
absent in fusca. Cell of primaries normal; vein 5 slightly 
curved, arising a little nearer to 4 than to 6. Mid tibiae with a 
few spines. Fig. 28. 

I believe that oslari is more closely related to A. nanno than 
to bellus, and am placing fusca in this genus rather doubtfully. 
Unfortunately I have not had sufficient material for dissection 
in this group and have therefore been unable to make a careful 
study of the anatomy of the doubtful species. I am unable to 
find a good basis of separation for fusca, which Godman and 
Salvin say belongs in Megistias, but I am not familiar with 
tripunctata so Megistias may not fall before Mastor, 

Key to the species 

1. Vestiture of head and fringes golden bellus 

Head golden ; fringes whitish phylace 

Without golden vestiture 2 

2. Under surface powdery gray oslari 

More or less yellowish below, never powdery gray fusca 

1. MASTOR FUSCA 

Hesperia fusca G. & R., Trans. Am. Ent. Soc. I, 2, 1867. 

Southern United States, New Jersey, Pennsylvania; April to July. St. 
Louis, Mo., (Knetzger). 

Fusca is usually immaculate grayish fuscous above and slightly tinged 
with yellowish below, especially on the veins of the secondaries. Occasion- 



98 



IOWA STUDIES IN NATURAL HISTORY 



al specimens show a faint trace of spots on the upper surface of the pri- 
maries, and frequently the ground color is darker. 

2. MASTOR BELLUS 

Pamphila hellus Edw., Papilio iv, 57, 1884. 
Biol. Cent. -Am., Ehop. n, 568, pi. 100, f. 36, $ gen., 1900. 
Skinner, Ent. News xi, pi. n, ff. 11, 12, 1900. 
Kellogg, Am. Ins. pi. ix, ff. 11, 12, 1904. 
Wright, Butt. W. Coast 247, pi. xxxi, f . 443, 1905. 
Arizona, May to July. 

3. MASTOR PHYLACE 

PampMla phylace Edw., Field and Forest in, 117, 1878. 
Arizona, Colorado, New Mexico; June. 

4. MASTOR OSLARI 

Pamphila oslari Skinner, Ent. News x, 112, 1899. 

New Mexico, Arizona, Colorado; April, June to August. 

Oslari is usually pale fuscous above, but occasionally a series will show 
some yellow fulvous scales on the disk of the primaries and a faint trace 
of indefinite spots such as are always present in A\ nanno. Such speci- 
mens may be separated from nanno by the gray under surface of the sec- 
ondaries with vague pale spots instead of small sharp ones. 

Genus AMBLYSCIRTES Scudder 
Amblyscirtes Scud., Syst. Rev. 54, (75), 1872. Type Hesperia 

vialis. Edw. 
Stomyles Scud., op. cit. 55 (76). Type Pyrgus textor Hbn. 

Palpi large, upturned; second 
joint with shaggy vestiture; third 
slender, smooth, vertical; almost as 
long as second except in nanno. An- 
tennae moderate; club large; apicu- 
lus longer than thickness of club. 
Primaries in most species similar in 
the two sexes, less apically produced 
than in the related genera; costa 
flattened ; apex rounded-rectangu- 
lar; outer margin strongly rounded 
except toward anal angle ; cell about 
three-fifths as long as wing ; discocel- 
Fig. 29. Aribfyscirtes vialis Edw. a. lulars very weak and only slightly 

Club of antenna.^ Palpus, c. oblique . vein 5 weakly curved 




HESPERIOIDEA OF AMERICA 99 

toward base, a little neater to 4 than to 6 ; secondaries rounded, 
in most of the species longer through the cell than in the related 
genera. Male stigma small, sometimes scarcely visible, composed 
of a short, oblique dash above the base of vein 2 and a smaller 
longitudinal dash below it. Middle tibiae spiny. Fig. 29. 

The checkered fringes of this genus are a convenient super- 
ficial character, and indeed the only one by which nanno can 
readily be placed. The other species are readily referred to the 
genus by the long third joint of the palpi, taken with the api- 
culus of the antennae. Whether nanno should be left in Ambly- 
scirtes is a question which I have been unable to settle ; its sim- 
ilar habitus would cause me to hesitate to remove it. 

Key to the species 

1. Vestiture of under surface of secondaries with no suggestion of green. 2 
Under surface of secondaries more or less greenish 9 

2. Spots on under surface of secondaries connected by /pale lines on 

veins textor 

No such lines 3 

3. Under surface of secondaries with diffused pale spots or immaculate . . 4 

With well defined pale spots 8 

With a brown patch in the middle nysa 

4. All maculation above yellow-fulvous cassus 

Subapical spots of primaries, at least, whitish 5 

5. Secondaries without pale spots below vialis 

With a transverse row of powdery pale spots 6 

6. Maculation of upper surface tinged with yellow-fulvous aenus 

No trace of yellow-fulvous 7 

7. Irroration of under surface smooth, fine alternata 

Irroration with a rough appearance celia 

8. Under surface dark, irroration sparse; spots small and powdery fout 

sharply contrasting nanno, elissa 

Under surface finely and smoothly grayish-irrorate ; spots very sharply 
defined, moderate comus 

0. Under surface pale greenish-gray; primaries with spots between veins 

4 and 6 above ; southwestern species nereus 

Darker greenish-gray; very bright in fresh specimens; spots at end of 
cell of primaries usually lacking ; eastern species hegon 

1. AMBLYSCIRTES NANNO 

Amblyscirtes nanno Edw., Papilio n, 142, 1882. 
Biol. Cent. -Am., Rhop. II, 504, pi. 95, ff. 31-34, 1900. 
Wright, Butt. W. Coast 250, pi. xxxi, f. 455, 1905. 
Arizona, July. 



100 IOWA STUDIES IN NATURAL HISTORY 

The primaries of nanno are more apically produced and the secondaries 
relatively smaller and more rounded than in the normal species of Ambly- 
scirtes. 

2. AMBLYSCIRTES ELISSA 

Amblyscwtes elissa G. & S., Biol. Cent. -Am., Ehop. h, 505, pi. 95, ff. 40, 

41, 1900. 
Skinner, Ent. News XV, 344, 1904. 

I have not seen this species. Apparently it is very similar to nanno. 
Skinner reports it from Cochise County, Arizona. 

3. AMBLYSCIRTES AENVS 
Amblyscirtes aenus Edw., Field and Forest m, 118, 1878. 
Holland, Butterfly Book 341, pi. xlvii, f. 7, 1898. 

Colorado, Texas, Arizona, New Mexico; May to July. 

4. AMBLYSCIRTES CASSUS 
Amblyscirtes cassia Edw., Papilio m, 72, 1883. 

Amblyscirtes simius Wright, (not Edw.), Butt. W. Coast pi. xxxi, f. 454, 
1905. 

Arizona; June, July and September. 

The under surface of the secondaries of cassus is heavily irrorate with 
pale gray scales which give these wings a roughened appearance. The 
spots are large and distinct but vaguely defined. 

5. AMBLYSCIRTES CELIA 

Amblyscirtes celia Skinner, Ent. News vi, 113, 1895. 

Texas, March, April and July. 

There is a specimen in the Barnes collection which has been compared 
with the type, and from which I have noted that the under surface of the 
secondaries is finely but rather sparsely and roughly powdered with gray; 
spots small but not clear-cut. 

6. AMBLYSCIRTES VIALIS 

Hesperia vialis Edw., Proc. Acad. Nat. Sci. Phil. 1862, 58, 1862. 
Scudder, Butt. New Eng. n, 1582, 1889. 
Holland, Butterfly Book 340, pi. xlvii, f. 5, 1898. 

United States and Southern Canada; May, June, July, August. 

7. AMBLYSCIRTES HEGON 

Hesperia hegon Scud., Proc. Ess. Inst, in, 176, 1863. 

Hesperia samoset Scud., op. cit. 176. 

Hesperia nemoris Edw., Proc. Ent. Soc. Phil, n, 507, 1864. 

Scudder, Butt. New Eng. n, 1589, 1889. 

Holland, Butterfly Book 340, pi. xlvii, f. 6, 1898. 

Georgia north into Canada and west to central Iowa; May and June; 
August in the north. 



HESPERIOIDEA OF AMERICA 101 

Hegon is more commonly known as samoset. It is similar to nereus but 
the transverse row of spots on the primaries is usually less complete and 
fresh specimens are much more greenish below. The distribution is suffi- 
cient to separate specimens which bear locality labels. 

8. AMBLYSCIRTES NEREUS 

Hesperia nereus Edw., Trans. Am. Ent. Soc. V, 207, 1876. 
Biol. Cent.-Am., Bhop. n, 502, pi. 95, ff. 27-30, 1900. 
Arizona, June to August. 

9. AMBLYSCIRTES ALTERNATA 

Hesperia altemata G. & R., Trans. Am. Ent. Soc. I, 3, 1867. 
Hesperia eos Edwards, Trans. Am. Ent. Soc. in, 276, 1871. 
Amblyscirtes meridionalis Dyar, Jn. N. Y. Ent. Soc. xm, 135, 1905. 

Georgia; Skinner lists eos from Texas, Georgia and Florida. 

A specimen which Dr. McDunnough placed as altemata in the Barnes 
collection proved to be the same as Dyar's types of meridionalis in the 
Strecker collection, and the descriptions of all of the species lead me to 
believe that they are synonyms. The primaries are apieally produced, so 
that the outer margin is longer than in vialis, and the fringes are an un- 
usually pure white, as in nysa. The under surface has a transverse row of 
faint, powdery spots on the secondaries and is otherwise similar to vialis. 

10. AMBLYSCIRTES NYSA 
Amblyscirtes nysa Edw., Can. Ent. ix, 191, 1877. 
Pamphila similis Strecker, Lep. Rhop. & Het. 131, 1878. 

Texas and Arizona, March to June. 

The under surface of the secondaries is distinctive and the fringes are a 
clearer white than in any other species than altemata. The upper surface 
of nysa is very similar to that of altemata in all particulars. 

11. AMBLYSCIRTES COMUS 

Hesperia comus Edw., Trans. Am. Ent. Soc. v, 206, 1876. 
Amblyscirtes nilus Edw., Field and Forest in, 118, 1878. 
Pamphila quinquemacwla Skinner, Ent. News xxn, 413, 1911. 
Biol. Cent. -Am., Ehop. n, 502, pi. 95, ff. 25, 26, 1900. 

Texas and Arizona, August. 

From a specimen in the Barnes collection compared with Edward's mate- 
rial I have noted that the under surface is finely and smoothly grayish 
irrorate and the spots small, white, sharply defined and not crowded to- 
gether. 

12. AMBLYSCIRTES TEXTOR 

Pyrgus textor, Hubner, Zutr. exot. Schmett. pi. 89, ff. 515, 516, 1825. 
Hesperia onelco Scud., Proc. Ess. Inst, in, 176, 1863. 
Hesperia waTculla Edw., Trans. Am. Ent. Soc. n, 311, 1869. 
Holland, Butterfly Book 341, pi. xlvii, f. 16, 1898. 



102 IOWA STUDIES IN NATURAL HISTORY 

North Carolina and Kentucky to Texas; August. 

The under side of the secondaries is very strikingly different from any 
other species, but I see no structural basis for Stomyles, of which textor 
is the type. 

Genus LERODEA Scudder 
Lerodea Scud., Syst. Rev. 59, 1872. Type Hesperia eufala Edw. 

Palpi upturned, very smoothly scaled; third joint about half 
as long as second but buried in vestiture of second almost to its 
tip. Antennae much less than one half as long as primaries; 
apiculus slender, shorter than thickness of club. Primaries api- 
eally produced; costa slightly emarginate or straight except at 
apex and humeral angle; outer margin slightly sinuate, convex 
from apex to vein 2. Secondaries rounded, lobed at anal angle. 
Both primaries and secondaries longer and more rounded in the 
female than in the male. Cell of primaries about three-fifths 
as long as wing; diseocellulars weak, scarcely oblique; vein 5 
almost straight, about two-thirds as far from 4 as from 6 ; 2 much 
nearer to 3 than to base of wing in both sexes. Male without 
stigma. Mid tibiae spined. Fig. 28. 

1. LERODEA ARABUS 

Pamphila arables Edw., Papilio n, 26, 1882. 

Arizona, April. 

Differs from eufala in the presence of a dark brown discal shade on the 
under surface of the secondaries. 

2. LERODEA EUFALA 

Hesperia eufala Edw., Trans. Am. Ent. Soc. n, 311, 1869. 
Pamphila floridae Mab., Bull. Soc. Ent. France (5), vi, p. ix, 1876. 
Holland, Butterfly Book 356, pi. xlvi, f. 33, 1898. 
Biol. Cent. -Am., Rhop. n, 500, pi. 95, ff. 16-18, 1900. 
Wright, Butt. W. Coast pi. xxxi, f. 445a, b, 1905 (as nereus). 
Florida, Texas, Arizona; April to July, October and November. 

GROUP D 
Key to the genera 

1. Middle tibiae without spines Prenes 

Middle tibiae spined 2 

2. Male with stigma ; under surface of secondaries mottled with 

several shades Thespieus 

Male without stigma ; under surface of secondaries uniform- 
ly colored Calpodes 



HESPEK10IDEA OF AMERICA 



103 



Genus THESPIEUS Godman & Salvin 
Thespieus G. & S., Biol. Cent.-Am., Rhop. n, 519, 1900. Type 
Hesperia dalmcmi La.tr. 
This genus is very close to Calpodes and the male genitalia of 
the two illustrated by Godman and Salvin are similar, but I 
have very little material of Thespieus and have not seen the 
typical species, so I hesitate to sink it. 

1. THESPIEUS MACABEUS 

Gonilooa macareus H.-S., Corr. Blatt Eegensb. xxm, 192, 1869. 
Biol. Cent.-Am., Ehop. n, 520, pi. 96, ff. 41-43, 1900. 
Skinner, Ent. News xm, 183, 1902. 

Macareus has been recorded from the southwestern part of our country 
and Marco Id., Fla.j I have not seen the species. 

Genus CALPODBS Hiibner 
Calpodes Hbn., Verz. bek. Schmett. 

107, 1820. Type Papilio eth- 

lius Cr. 
Palpi upturned, closely ap- 
pressed; third joint small, almost 
entirely concealed. The palpi re- 
semble those of most species of 
Group A of the Hesperiinae. An- 
tennae less than one-half as long as 
primaries; club stout, apiculus ex- 
ceeding thickness of club, sharply 
reflexed. Primaries with the apex 
produced and subtruncate, longer 
in the female than in the male; 
secondaries strongly lobed at the 
anal angle, broader and more 

rounded in the female than in the male. Neuration as in Prenes. 
Mid tibiae with short prostrate spines on the inner surface. 
Fig. 30. 

1. CALPODES ETHLIUS 
Papilio ethlms Cramer, Pap. Exot. rv, 212, pi. cocxcn, ff. A, B, 1782. 
Hesperia chemnis Fab., Ent. Syst. in, (i), 331, 1793. 
Mudamus olynthus Bd. & L»ec., Lep. Am. Sept. pi. 75, ff. 1, 2, 1833. 
Scudder, Butt. New Eng. n, 1750, 1889. 
Holland, Butterfly Book 355, pi. xlv, f. 3, 1898. 




Fig. 30. Prenes and Calpodes. a. 

Club of antenna of P. ocola Edw., 

b. Neuration of ocola, c. Club of 

antenna of C. ethlius Cramer 



104 IOWA STUDIES IN NATURAL HISTORY 

Biol. Cent.-Am., Rhop. n, 507, pi. 95, ff. 45, 46, 190O. 

Florida to Texas, June. Skinner lists it as occasional in New York, 
(Cat. p. 88). St. Louis, Mo., (Knetzger). 

Ethlius is readily distinguished by its large size, the long cell of the 
primaries, the form of the palpi and the presence of hyaline spots on the 
secondaries. 

2. CALPODES COSCINIA 

Goniloba coscinia H.-S., Corr.-Blatt Regensb. xix, 54, 1865. 
? Hesperia ares Feld., Verh. z.-b. Ges. Wien xn, 477, 1862. 

Brownsville and San Antonio, Texas, May. 

Barnes and McDunnough list ares as a doubtful synonym of coscinia 
while Godman and Salvin in the Biologia make it a synonym without qual- 
ification. If the two names refer to the same species, ares should be used; 
I know of nothing which will settle the matter at present. Coscinia differs 
from ethlius and T. macareus in the absence of hyaline spots from the 
secondaries. 

Genus PRENES Scudder 
Prenes Scud., Syst. Rev. 60, (81), 1872. Type Hesperia pano- 
quin Seud. 

Similar to Calpodes but with the wings more angular and the 
mid tibiae without spines. Fig. 30. 

Prenes is very close to the Old World genus Parnara and may 
fall before it. Dr. W. T. M. Forbes tells me that he is unable to 
separate the two, and from a superficial study of the genotypes 
I have found nothing which will differentiate them. I prefer to 
retain Prenes, however, until I can make dissections of the type 
of Parnara for more accurate study. 

Key to the species 

1. Secondaries with a few pale spots below 2 

Secondaries immaculate below or with pale dashes or very faint traces 
of spots 4 

2. Upper surface powdered with yellowish scales panoquinoides 

Upper surface without yellowish scales 3 

3. A pale spot in end of cell of primaries; spots on under surface 

bluish nero 

No spot in cell ; spots below not bluish errans 

4. Two pale dashes on under surface of secondaries. panoquin 

Usually immaculate ; never with dashes ocola 

1. PRENES NERO 

Hesperia nero Fab., Ent. Syst., Supp. 433, 1798. 
Hesperia nyctelius Latr., Enc. Meth. ix, 746, 1823. 



HESPEEIOIDEA OF AMERICA 105 

Gonilooa corrupta H.-S., Corr.-Blatt Eegensb. xix, 54, 1865. 

Gonilooa sylvicola H.-S., op. eit., p. 55. 

Hesperia fusina Hew., Desc. Hesp. 30, 1868. 

Hesperia fufidia Hew., Ann. & Mag. Nat. Hist. (4), xix, 81, 1877. 

Biol. Cent.-Am., Khop. n, 509, pi. 96, ff. 4-7, 1900. 

Florida. 

Differs from ocola in the presence of a pale spot in the end of the cell 
of the primaries and a transverse row of faint, bluish spots on the under 
surface of the secondaries. The synonymy is that of Godman and Salvia. 

2. PRENES PANOQUIN 

Hesperia panoquin Scud., Proc. Ess. Inst, in, 178, 1863. 
Hesperia ophis Edw., Trans. Am. Ent. Soc. in, 216, 1871. 
Scudder, Butt. New Eng. m, 1867, 1889. 
Skinner, Ent. News xi, pi. n, ff. 13, 14, 1900. 
Kellogg, Am. Ins. pi. ix, ff. 13, 14, 1904. 
Florida, New Jersey; April, May, August. 

3. PRENES PANOQUINOIDES 

PamphUa panoquinoides Skinner, Ent. News n, 175, 1891. 
Skinner, Ent. News xi, pi. n, f. 26, 1900 (type). 
Kellogg, Am. Ins. pi. ix, f. 26, 1904 (type). 

Florida. This species is slightly powdered with yellowish scales above 
but less heavily than panoquin, from which it differs also in the absence of 
the large dashes of the under surface. 

4. PRENES ERRANS 

PamphUa errans Skinner, Ent. News in, 174, 1892. 
Wright, Butt. W. Coast pi. xxxi, f. 445, 1905 (as nereus). 

California, July and August. 

Differs from ocola, which it closely resembles, in the presence of a trans- 
verse row of pale spots on the under side of the secondaries, which are not 
bluish as in nero, 

5. PRENES OCOLA 

Hesperia ocola Edw., Proc. Ent. Soc. Phil, n, 20, pi. xi, f. 4, 1863. 

Prenes heceoolus Scud., Syst. Eev. 60, (81), 1872. 

PampMla ortygia Moschl., Verh. z.-b. Ges. Wien xxxn, 328, 1882. 

Scudder, Butt. New Eng. m, 1866, 1889. 

PampMla parilis Mab., Comp. Rend. Soc. Ent. Belg. XXXV, clxxi, 1891. 

Holland, Butterfly Book 355, pi. xlvi, f. 34, 1898. 

Biol. Cent.-Am., Rhop. n, 511, pi. 96, ff. 13-15, 1900. 

Kentucky, Florida, Mississippi and Texas; May, July to October. Skin- 
ner (Cat. p. 88) adds Indiana and Eastern Pennsylvania. 

Ocola is usually immaculate below but some specimens show a trace of 
the spots which mark errans, though they are not, as a rule, sufficiently 
well marked as to cause difficulty in separating the species. They never 



106 IOWA STUDIES IN NATUEAL HISTORY 

have the marked blue shade found in nero. In the synonymy of ocola I 
follow Godman and Salvin (Biol. 511), who say that they have seen the 
types of all three synonyms and find them to l ' show no tangible difference. ' ' 

DOUBTFUL SPECIES AND GENERA 
Genus POTANTHUS Scudder 
Potanthus Scud., Syst. Eev. 54, (75), 1872. Type Hesperia 
ornaha Edw. 

1. POTANTHUS OMAHA.. 

Eesperia omaha Edw., Proc. Ent. Soe. Phil, n, 21, 1863. 

Hesperia mingo Edw., Proc. Ent. Soc. Phil, vi, 207, 1866. 

Potanthus calif omica Scud., Syst. Eev. 54, (75), 1872. 

Seudder, Butt. New Eng. in, 1861, 1889. 

Potanthus dara Dyar (Kollar?), Bull. 52, U. S. N. M., p. 48, 1902. 

The early literature gives the range of this species as West Virginia, 
Colorado and California. Edwards places the species next to palaemon in 
his catalogue (Cat. Diurn. Lep. 48, 1877), and Dyar regards it as the 
Oriental species, Padraona dara Kollar. It is very difficult to say what it 
may be from the scanty evidence available. 

2. ATRYTONE KUMSKAKA 

Eesperia conspicua Scud, (not Edw.), Trans. Chi. Acad. Sci. I, 336, 1869. 
Atrytone ~kumskaka Scud., Can. Ent. xix, 45, 1887. 

According to the description this is a true Atrytone which Scudder has 
mistaken for the female of conspicua. Dr. McDunnough tells me that 
Scudder 's figure of the male genitalia resembles those of byssus, but it 
seems to me that the description itself suggests a dark female of hobomolc. 
The type locality is Dennison, Iowa, but I have never taken anything in 
western Iowa which might be the species. 

3. THANA08 BUTILIUS (nomen nudum) 
Nisoniades rutilius Mead, U. S. Geog. Surv. W. 100th Merid. v, 787, 1875. 
The reference reads as follows: "One individual, now in Mr. Scudder 's 
hands for description, was taken June 23, at Turkey Creek Junction. ' ' The 
specimen was probably placed by Scudder with another species. 

Family MEGATHYMIDAE 
Barnes and McDunnough, Contributions i, number in, 1912, Re- 
vision of the Megathymidae. 
Head small, much narrower than the thorax. Palpi rather 
small, oblique. Antennae moderate ; club large, stout and pyri- 
f orm to more cylindrical with a rudimentary apiculus. Venation 
much as in the Pamphilinae ; vein 3 of the primaries varying in 



HESPERIOIDEA OF AMERICA 107 

position between the sexes of several species. Larvae borers in 
stems of plants. Fig. 31. 

Barnes and McDunnough's revision of this family is so satis- 
factory that I am going into very little detail in 
treating it. I have worked out the following key 
to the North American species of Megathymus Fig. 31. Megathy- 
from the material in the Barnes collection, and ^r**c7ub e ?f a'n- 
believe that it will suffice for the determination of tenna 

most of the material likely to fall into the hands of collectors ; 
those who are deeply interested in the family will doubtless ob- 
tain the few articles which are useful to students who make these 
insects a hobby. Only one genus is represented in our fauna. 

Genus MEGATHYMUS Scudder 
Megathymus Scud., Syst. Rev. 62, (83), 1872. Type Eudamus 
yuccas Boisd. & Lee. 
Characters of the family. 

Key to the species 

1. Under surface with a large white patch contiguous to vein 8 of the 
secondaries, or this spot the largest on the wing; no more than a trace 

of extra-median pale spots on secondaries yuccae 2 

Under surface of secondaries with a more or less complete transverse 
row of pale spots and with larger spot on vein 8 outward 3 

2. Size large, 55 to 75 mm. Spots of upper surface bright yellow. Under 

surface of secondaries gray at margins yuccae 

Size smaller, seldom over 55 mm. Spots pale yellow. Outer margin 

of secondaries narrowly or not at all pale race coloradensis 

Size similar to coloradensis. Spots yellowish to white. Secondaries 
with a broad pale outer border race navajo 

3. Size very large, 65 to 90 mm. Spots of primaries bright yellow. Sec- 
ondaries without discal spots above and with at most a slender, linear 

pale margin ursus 

Size smaller, not over 70 mm. Secondaries with discal spots, a crenu- 
late marginal band or with pale areas not bright yellow 4 

4. Under surface of secondaries smooth, powdered with blue-gray scales 

at outer margin cofaqui 

Under surface of shaggy appearance, washed with gray scales and hairs 
over entire surface, sometimes most evidently between transverse row 
of spots and outer margin 5 

5. Upper surface of primaries with a pale basal area contiguous to vein 
1; spots yellow to yellowish-fulvous, or with a transverse sub-basal 

row of spots on the under surface of the secondaries 6 

This area seldom present, if so powdery and not contiguous to vein 1 



108 IOWA STUDIES IN NATURAL HISTORY 

and with maculation not bright yellow. No transverse row of spots 
near base of secondaries below 7 

6. Expanse 40 to 50 mm. Larger specimens females with pale spots of 

primaries broadly confluent and veins coneolorous polmgi 

Expanse 50 to 70 mm., smaller specimens males with spots separated 

by dark veins or by broader dark areas aryxna, newmoegeni 

Expanse 50 mm. or slightly over. Spots small, rounded and whitish. 
Southern California race stephensi 

7. Spots yellowish white to pale yellow; at least one extra-discal spot on 

under surface of secondaries and rarely some above streckeri 

Spots deeper yellow; extra-discal spots obsolete, not more than one or 

two fine points present, or with discal spots above race texana 

Spots greatly reduced, yellowish; extra-discal band on under surface 
of secondaries evenly curved but irregular. Spot in end of cell of 
primaries linear, bent, in apical angle smithii 

1. MEGATHYMUS YUCCAE 

Eudamus yuccae Boisd. & Lee, Lep. Am. Sept. pi. 70', 1833. 
Riley, 8th Rep. St. Ent. Mo., 169-182, 1876 (Biol.). 
Florida, Georgia, South Carolina; April and May. 

la. race COLOBADENSIS 
M. yuccae, var. coloradensis Riley, Trans. Acad. Sei. St. Louis in, 567, 1877. 
Colorado, April. 

lb. race NAVAJO 
M. yuccae, var. navajo Skinner, Ent. News xxn, 300, 1911. 
Skinner, Trans. Am. Ent. Soc. xxxvu, 209, pi. x, 1911. 

Texas, New Mexico, Arizona, S. California; April to June. 

2. MEGATHYMUS URSUS 

Megathymus ursus Poling, Ent. News xm, 97, pi. 4, 1902. 
Skinner, Trans. Am. Ent. Soc. xxxvu, 205, 1911. 
Pima County, Arizona; August. 

3. MEGATHYMVS COFAQUI 

Aegiale cofaqui Strecker, Proc. Acad. Nat. Sci. Phil. 148, 1876. 
Skinner, TTans. Am. Ent. Soc. xxxvu, 203, 1911. 

Georgia, Florida; March. 

The male type is a form of streckeri to which Barnes and MeDunnough 
have given the name texana. The female type represents cofaqui. This 
sex may be distinguished by the slightly emarginate outer margin of the 
primaries and the resultant sharpness of the apex. 

4. MEGATHYMUS STRECKERI 

Aegiale streckeri Skinner, Can. Ent. xxvn, 179, 1895. 
Skinner, Trans. Am. Ent. Soc. xxxvii, 204, 1911. 



HESPERIOIDEA OF AMERICA 109 

Southwestern Colorado, New Mexico, Cherry County, Nebraska (Leus- 
sler) ; May and June. 

race TEXAN A 
M. streckeri, subsp. texana B. & McD., Contr. i, no. in, 39, pi. n, f. 9, 1912. 
Southern Texas. 

5. MEGATHYMUS SMITHI 

Megathymus smithi Druee, Mol. Cent.-Am., Het. n, 320, pi. 69, f. 5, 1896. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 205, 1911. 

I have seen one specimen from Corpus Christi, Texas, in the Barnes 
Collection. 

6. MEGATHYMUS NEUMOEGENI 

Megathymus neumoegeni Edw., Papilio n, 27, 1882. 

Megathymus aryxna Dyar, Jn. N. Y. Ent. Soe. xin, 141, 1905 (partim) ; 

(fide B. & McD.). 
Skinner, Trans. Am. Ent. Soe xxxvii, 206, 1911. 
Skinner, Trans. Am. Ent. Soe. xxxvii, 207, 1911 (fide B. & McD.). 

Arizona, September. 

According to Barnes and McDunnough's revision the females can read- 
ily be separated from aryxna. They say: "in every instance the $ could 
be separated at once on wing pattern, the yellow band on primaries being 
much broader and either touching or broadly coalescing with the costal 
spot at end of cell." Of the male they say that neumoegeni is usually 
a smaller and slighter species, and give the following points of difference: 

"(1) in neumoegeni the spots are often small, well separated, irregu- 
larly rounded; when forming a more or less eoalescent band spot 2 from 
anal angle is usually almost square and its inner margin is not prominent- 
ly wedge-shaped as in aryxna. 

" (2) The fulvous hairing at base of both wings is much more extended 
in neumoegeni^ covering on the secondaries most of the area between the 
subterminal spots and the base of wing. The presence or size of yellow 
spots in the basal area beneath the fulvous hairs we have found of no 
specific value. 

"(3) The underside of secondaries of neumoegeni is usually distinctly 
paler in color, due to a greater sprinkling of white scales (compare Figs. 
2 and 7). The whitish subterminal band is very variable in both species, 
in both distinctness and extent, and of no value for purposes of separa- 
tion.' ' 

In spite of this great similarity of the two species, the form of the male 
genitalia verifies their distinctness. 

6a. race STEPHENSI 
Megathymus neumoegeni Wright (not Edw.), Butt. W. Coast 255, pi. xxxii, 
f. 483, 1905. 



110 IOWA STUDIES IN NATUEAL HISTOEY 

Megathymus neumoegem subsp. stephensi Skinner, Ent. News xxm, 126, 

1912. 
Barnes & McDunnough, Contributions I, (5), 44, 1912. 
Southern California, Texas. 

7. MEGATHYMUS ARYXNA 

Megathymus aryxna Dyar, Jn. N. Y. Ent. Soc. xm, 141, 1905. 
Arizona; July, September and October. 

8. MEGATHYMUS POLINGI 

Megathymus polingi Skinner, Ent. News xvi, 232, 1905 ( $ only, fide B. & 

McD.). 
Skinner, Trans. Am. Ent. Soc. xxxvn, 207, 1911. 
Arizona, September. 



BIBLIOGRAPHY 

Part one includes all separate works and articles bearing particularly on 
the Hesperioidea. Part two contains a list of the periodicals consulted. 
References occurring in all of the works listed have been verified; others 
are copied from the best available authorities. 

PART? I 

Abbott & Smith, The Natural History of the Rarer Lepidopterous Insects 
of Georgia, two volumes, London, 1797. 

Banks, ( N. and Caudell, A. N., The Entomological Code, Washington, 
D.C., 1912. 

Barnes, Wm. and McDunnough, J., Revision of the Megathymidae, De- 
catur, 111., 1912. 

Check List of the Lepidoptera of Boreal America, Decatur, 111., 1917. 

Contributions to the Natural History of the Lepidoptera of North 

America, I, 1911-12. 

Boisduval, J. A., Icones Historique des Lepidopteres d 'Europe, Paris, 
1832-43. 

and LeConte, J. L., Histoire Generale et Iconographie des Lepidop- 
teres et des Chenilles de L'Amerique Septentrionale, Paris, 1829-33. 

Butler, A. G., Lepidoptera Exotica, London, 1869-74. 

Catalogue of Diurnal Lepidoptera Described by Fabricius in the 

Collection of the British Museum, London, 1869. 

Oomstock, J. H. and A. B., Manual for the Study of Insects, Ithaca, N. 

Y., 1895. 
€ramer, P., Papillons Exotiques des trois parties du Monde, l'Asie, l'Afri- 

que at l'Amerique, Amsterdam, I, 1775 to IV, 1782, and supplement 

by Stoll, 1787-1796. 
Boubleday, E., Westwood, J. O. and Hewitson, W. C, The Genera of 

Diurnal Lepidoptera, London, I, 1846; II, 1850. 
Drury, D., Illustrations of Exotic Entomology, London, three vol., 1770- 

1775. 
Dyar, H. G., A List of the North American Lepidoptera and Key to the 

Literature of this order of Insects, Bulletin 52, U. S. N. M., Wash- 
ington, D.C., 1902. 

A Review of the Hesperiidae of the United States, Jn. N. Y. Ent. 

Soc. xin, 111-142, 1905. 

Edwards, W. H., Catalogue of the Lepidoptera of America North of Mex- 
ico, Trans. Am. Ent. Soc. VI, 1-68, 1877. 

Elwes, H. J., and Edwards, James, A Revision of the Oriental Hesperiidae, 
Trans. Zool. Soc. London xiv, pt. rv, number 1, 1897. 



112 IOWA STUDIES IN NATURAL HISTORY 

Fabricius, J. C, Systema Entomologiae, Flensburg and Leipzig, 1775. 

Mantissa Insectorum, Copenhagen, 1787. 

Entomologia Systematica, Vol. in, Copenhagen, 1793. 

Supplementum Entomologiae Systematicae, Copenhagen, 1798. 

Felder, C, and Rogenhofer, E., Reise der osterreichischen Fregatte No- 

vara urn die Erde, Zoologischer Theil, II, Abth. 2, Vienna, 1864-67. 
French, G. H., Butterflies of the Eastern United States, Philadelphia, 1886. 
Godman, F. D. and Salvin, O., Biologia Centrali-Americana, Lepidoptera 

Ehopalocera, Vol. II, 1893-1901, and plates, Vol. Ill, London. 
Harris, T. W., A Treatise on Some Insects Injurious to Vegetation, third 

edition, Boston, 1862. 
Herrich-Schaffer, G. A., Prodromus Systema Lepidopterorum, in Corr.- 

Blatt Regensb. 
Hewitson, W. C, Descriptions of New Species of Hesperiidae, London, 

Part 1, pp. 1-25, 1867; part 2, pp. 25-26, 1868. 
Holland, W. J., The Butterfly Book, New York, 1898. 
Hubner, J., Verzeichniss bekannter Schmetterlinge, Augsburg, 1816-1820. 

Sammlung exotischer Schmetterlinge, and Zutrage zur Sammlung, 

partly by Geyer, Augsburg, 1818-1832. 

Kirby, W. F., A Synonymic Catalogue of Diurnal Lepidoptera, London, 

1871; Supplement, 1877. 
Kirby, Wm., Fauna Boreali- Americana, iv, The Insects, London, 1837. 
Latreille, P. A., Encyclopedic Methodique, ix, Article on Butterflies, Paris, 

1819. 
Linnaeus, C, Systema Naturae, tenth edition, Stockholm, 1758. 
Lintner, J. A., Entomological Contributions, I, 1872 to IV, 1878, (Annual 

Report of the New York State Museum of Natural History, Albany). 
Lucas, H., in Sagra's Historia fisica, politica y naturel de la isla de Cuba, 

Vol. vn, Paris, 1856. 
Mabille, P., Famille Hesperidae, Genera Insectorum, Vol. xvn, Brussels, 

1903-4. 
Menetries, E., Enumeratio corporum animalium musei imperialis Acad- 

emiae scientiarum Petropolitaniae, St. Petersburg, 1855-1863. 
Mead, T. L., Report on the Collection of Diurnal Lepidoptera, etc., U. S. 

Geographical Surveys West of the 100th Meridian, v, ch. 8, 1875. 
Oberthur, C, Etudes d 'entomologie and Etudes de Lepidopterologie Com- 

paree, Rennes, I, 1876. 
Soudder, S. H., A Systematic Review of American Butterflies, etc., Re- 
port of the Peabody Academy of Science for 1872, pp. 22-83. 

Historical Sketch of the Generic Names Proposed for Butterflies, 

Boston, Proceedings of the American Academy of Arts and Sciences, 
Vol. x, pp. 91-293, 1875. 

The Species of the Lepidopterous Genus Pamphila, Bbston, Me- 
moirs of the Boston Society of Natural History, Vol. n, part in, num- 
ber iv, 1874. 



HESPERIOIDEA OF AMERICA 113 

— > The Butterflies of the Eastern United States and Canada, with 
a special reference to New England, Cambridge, three Vol., 1888-1889. 
and Burgess, E., On Asymmetry in the Appendages of . . . 



Nisoniades, Proc. Bost. Soc. Nat. Hist, xm, 282, 306, 1870. 
Seitz, A., The Maerolepidoptera of the World, Vol. I, The Palaearctic 

Butterflies, Stuttgart, 1909. Hesperiidae by P. Mabille. 
Skinner, H., A Synonymic Catalogue of the North American Rhopalocera, 

Philadelphia, 1898, and supplement to end of 1904. 
. The Larger Boreal American Hesperiidae, Trans. Am. Ent. Soc. 

xxxvn, 169-209, pi. x, Philadelphia, 1911. 
Studies in the Genus Thanaos, Trans. Am. Ent. Soc. XL-, 195-221, 



Philadelphia, 1914. 

Spuler, Die Schmetterlinge Europas, four vol., Stuttgart, 1908-10. 

Staudinger, O., Exotische Tagfalter, etc., Furth, 1888. 

Strecker, H., Lepidoptera, Rhopalocera and Heterocera, Indigenous and 
Exotic, Reading, Pa., 1872-78. 

Tutt, J. W., British Butterflies, I, 1905-6. 

Watson, E. Y., A Proposed Classification of the Hesperiidae, with a Re- 
vision of the Genera, Proceedings of the Zoological Society of London, 
1893, pp. 3-132, pi. i-iii. 

Wright, W. G., Butterflies of the West Coast, San Francisco, 1905. 

PART II 

American Entomologist and Botanist, New York, 1880. 

Annales de la Societe entomologique beige, Brussels, I, 1857. 

Annales de la Societe entomologique de France, first series, I, 1832 (now 

running without series number). 
Annals and Magazine of Natural History, London, first series, I, 1838. 
Bulletin of the Brooklyn Entomological Society, I, 1878-VII, 1885. 
Bulletin of the Buffalo Society of Natural Science, 1873. 
Canadian Entomologist, I, 1869. 
Cistula Entomologica, London, I, 1869-III, 1885. 
Correspondenz-Blatt des zoologisch-mineralogischen Vereins in Regensburg, 

Ratisbon, I, 1847. 
Entomologica Americana, Brooklyn, I, 1885-VI, 1890. 
Entomological News, Philadelphia, I, 1890. 
Entomologische Zeitung, herausgegeben von dem entomologisehe Verein zu 

Stettin, Stettin, I, 1840. 
The Entomologist, London, I, 1839. 
Entomologists ' Monthly Magazine, London, 1864. 
Field and Forest, Washington, D.C., I, 1875-III, 1877-78. 
Illiger, Magazin fur Insectenkunde, Brunswick, I, 1801-VI, 1807. 
Jahrbueher des Nassauischen Vereins fur Naturkunde, Wiesbaden, 1844. 
Journal of the Academy of Natural Sciences of Philadelphia, I, 1917. 
Journal of the New York Entomological Society, New York, I, 1893. 
Memoirs of the Boston Society of Natural History, Boston, 1866. 
Papilio, New York, I, 1881-IV, 1884. 



114 IOWA STUDIES IN NATURAL HISTORY 

Proceedings of the Academy of Natural Sciences of Philadelphia, 1841. 
Proceedings of the California Academy of Sciences, San Francisco, I, 1864. 
Proceedings of the Entomological Society of Philadelphia, I, 1861-VI, 1867. 
Proceedings of the Essex Institute, Salem, 1848-1870. 
Proceedings of the United States National Museum, Washington, D.C., I, 

1878. 
Proceedings of the Zoological Society of London, London, 1832. 
Psyche, Cambridge, I, 1874. 

Report of the Entomological Society of Ontario, Toronto, 1871. 
Report of the Peabody Academy of Sciences, Salem, I, 1868- VI, 1873. 
Transactions of the American Entomological Society, Philadelphia, 1867. 
Transactions of the Chicago Academy of Sciences, Chicago, I, 1867. 



FIRST SERIES NO. 45 MARCH 15, 1921 



UNIVERSITY OF IOWA 
STUDIES 



STUDIES IN NATURAL 
HISTORY 

VOLUME IX NUMBER 5 



REPORTS ON THE CRINOIDS, OPHIU- 
RANS, BRACHYURA, TANIDACEA AND 
ISOPODA,AMPHIPODS,^ECHINOIDEA 

of the Barb ados- Antigua Expedition of 1918 



PUBLISHED BY THE UNIVERSITY, IOWA CITY 

Issued semi-monthly throughout the year. Entered at the post office at Iowa City, 
Iowa, as second class matter, Acceptance for mailing at special rates of postage 
provided for in section 1103, Act of October 3, 1917, authorized on July 3, 1918. 



UNIVERSITY OF IOWA STUDIES 
IN NATURAL HISTORY 

Professor Charles Cleveland Nutting, M. A., Editor 



CONTINUATION OF BULLETIN FROM THE LABORATORIES OF NATURAL HISTORY 
OF THE STATE UNIVERSITY OF IOWA 



VOLUME IX NUMBER 5 



REPORTS ON THE CRINOIDS, OPHIU- 
RANS, BRACHYURA, TANIDACEA AND 
ISOPODA,AMPHIPODS,^fECHINOIDEA 

of the Barbados- Antigua Expedition of 1918 



The Crinoids Austin H. Clark 

The Ophiurans Austin H. Clark 

The Brachyura Mary J. Rathbun 

The Tanidacea and Isopoda Pearl L. Boone 

The Amphipods Clarence R. Shoemaker 

The Echinoidea Hubert Lyman Clark 



PUBLISHED BY THE UNIVEESITY, IOWA CITY 



CONTENTS 



Crinoids 1-28 

Ophiurans 29-64 

Brachyura 65-90 

Tanidacea and Isopoda 91-98 

Amphipods 99-102 

Echinoidea 103-121 



REPORT ON THE CRINOIDS 

Collected by the Barbados-Antigua Expedition 
from the University of Iowa in 1918 

Austin H. Clark 

Curator, Division of Echinoderms, U. S. National Museum 



PREFACE 



It was most gratifying to me to be honored with a request to 
prepare an account of the crinoids of the State University of 
Iowa's Barbados- Antigua Expedition for I have myself visited 
Barbados four, and Antigua three times in connection with my 
studies on the terrestrial fauna of the West Indies, and I natur- 
ally take a keen interest in everything that concerns these 
islands. 

Perhaps it may not be out of place here to list the titles of my 
previous contributions to the zoological literature of the Lesser 
Antilles. These are the following: 

[A reply to Mr. P. Foster Huggins; deals with birds]. The Sentry, 
Kingstown, St. Vincent, vol. 13, issue of Friday, November 20, 
1903, p. 2. 

The Birds of St. Vincent. West Indian Bulletin (Barbados), vol. 5, 

No. 1, pp. 75-95, 1904. 
Notes on the Inseets of Barbados, St. Vincent, the Grenadines and 

Grenada. Psyche, vol. 11, pp. 114-117, December, 1904. 
Description of a new Euphonia from the southern West Indies. Proc. 

Biol. Soc. Washington, vol. 18, pp. 19-22, February 2, 1905. 
Preliminary descriptions of three new Birds from St. Vincent, West 

Indies. Proc. Biol. Soc. Washington, vol. 18, pp. 61-64, February 

21, 1905. 
The Migrations of certain Shore Birds. The Auk, vol. 22, No. 2, pp. 

134-140, April, 1905. 
An unrecognized Subspecies of Bellona cristatm. The Auk, vol. 22, 

No. 2, pp. 215-216, April, 1905. 
Shore Birds eating small Fish. The Auk, vol. 22, No. 2, pp. 208-209, 

April, 1905. 



4 IOWA STUDIES IN NATURAL HISTORY 

The Crab Hafc T k (Urubitinga) in the Island of St. Lucia. The Auk, 

vol. 22, No. 2, p. 210, April, 1905. 
A supposed Specimen of the Yellow Warbler (Dendroica aestiva) from 

Grenada, West Indies. The Auk, vol. 22, No. 2, pp. 212-214, 

April, 1905. 
Habits of West Indian Whitebait. American Naturalist, vol. 39, 

No. 461, pp. 335-337, May, 1905. 
Extirpated West Indian Birds. The Auk, vol. 22, No. 3, pp. 259- 

266, July, 1905. 
The Lesser Antillean Macaws. The Auk, vol. 22, No. 3, pp. 266- 

273, July, 1905. 
The Genus Conurus in the West Indies. The Auk, vol. 22, No. 3, pp. 

310-312, July, 1905. 
The former status of the Flamingo and the Fish Hawk in the Lesser 

Antilles. The Auk, vol. 22, No. 3, pp. 318-319, July, 1905. 
Birds of the southern Lesser Antilles. Proc. Boston Soc. Nat. Hist., 

vol. 32, No. 7, pp. 203-312, October, 1905. 
The West Indian Parrots. The Auk, vol. 22, No. 4, pp. 338-344, 

October, 1905. 
The Greater Antillean Macaws. The Auk, vol. 22, No. 4, pp. 345- 

348, October, 1905. 
The West Indian black Forms of the Genus Ccereba. The Auk, vol. 

23, No. 4, pp. 392-395, October, 1906. 
The Macaw of Dominica. The Auk, vol. 25, No. 3, pp. 309-311, 

July, 1908. 
A list of the Birds of the Island of St. Lucia. West Indian Bulletin 

(Barbados), vol. 21, No. 3, pp. 182-192, May, 1911. 
Piccole Note su degli Onychophora. Zool. Anzeiger, vol. 42, No. 6, 

pp. 253-255, July 18, 1913. 
Two interesting mammals from the Island of Tobago, West Indies. 

Ann. and Mag. Nat. Hist. [8], vol. 13, pp. 68-70, January, 1914. 
The present Distribution of the Onychophora, a Group of terrestrial 

Invertebrates. Smithsonian Miscellaneous Collections, vol. 65, 

No. 1, pp. 1-25, January 4, 1915. 
The present Status and Breeding Season of the Giant Toad (Bufo 

agua) in Barbados, St. Vincent, Trinidad and Demerara. Copeia, 

No. 27, February 24, 1916, pp. 13-14. 

My notes on the mammals of the Lesser Antilles with refer- 
ences to the specimens obtained are incorporated in the following 
paper : 

Mammals of the West Indies, by Glover M. Allen. Bull. Mus. Comp. 



BARBADOS-ANTIGUA REPORTS 5 

ZooL, vol. 54, No. 6, pp. 175-263, July, 1911. [On p. 201 under 
Leporidse the heading Oryctolagus cuniculus should read Lepus 
europaeus, and Lepus europaeus in the last line on the page should 
read Oryctolagus cuniculus.] 



HISTORICAL INTRODUCTION 

The island of Barbados has long been well known as a locality 
for recent erinoids. The first recent stalked crinoid discovered 
was a specimen of Isocrinus asteria from Martinique described 
by Ouettard under the name of "Palmier marin" in 1761; but 
in the very next year Ellis described another specimen of the 
same species from Barbados. A second individual from Bar- 
bados was described by J. S. Miller in 1821, together with one 
from Nevis. 

The second known recent stalked crinoid was also from Marti- 
nique, and was described by d'Orbigny in 1837 under the name 
of Holopus rangii. It had only four rays, and was altogether 
such an extraordinary form that Dujardin and Hupe in 1862 
suggested that possibly it was a barnacle rather than a crinoid. 

In 1871 Mr. (later Sir) Rawson W. Rawson, the Governor of 
Barbados, sent to Dr. J. E. Gray a drawing of another specimen 
of this species which was published by the latter under the name 
of Holopus rawsoni. The actual specimen Gray never saw. 

During his residence at Barbados Sir Rawson Rawson was so 
fortunate as to obtain, in addition to several specimens of Holo- 
pus rangii, examples of Isocrinus decorus and Endoxocrinus 
parrce, and of several species of comatulids. 

In 1858 d'Orbigny described from a recent breccia at Guade- 
loupe, which also contained a human skeleton, a fragment of a 
crinoid which he called Bourgueticrinus hotessieri. In 1871 the 
United States Coast Survey steamer "Hassler" dredged some 
specimens of a closely related, possibly the same, species off 
Sandy Bay, Barbados, which were described by Count Pourtales 
in 1874 under the name of Rhizocrinus rawsonii. 

Comatulids were first reported from the West Indies in 1825 
by the Reverend Lansdown Guilding of St. Vincent, who men- 
tioned them incidentally in connection with the description of a 
new pentacrinite which he called Encrimis milleri. In this paper 



6 IOWA STUDIES IN NATURAL HISTORY 

he published the first notice of the curious brachial articulation 
now known as the syzygy. 

Sir Rawson Rawson had secured a number of comatulids at 
Barbados, but the first published record for that island was 
Pourtales ' description of Antedon [Neocomatella] pulchella and 
A. [N.] alata, which appeared in 1878. 

In 1912 Dr. Clemens Hartlaub's memoir on the comatulids 
collected by the United States Coast Survey steamer "Blake" 
was published, in which were listed a number of species from 
twenty stations off Barbados. Isolated records of individual 
specimens from Barbados appeared in 1912 and 1913. 

THE OCCURRENCE OF ISOCRINUS ASTERIA 
AND OF HOLOPUS 

It is an extraordinary fact that in spite of all the dredging 
that has been done in the Caribbean Sea and about the West 
India Islands only four specimens of Isocrinus asteria have been 
brought up, one at Montserrat by the " Blake/ ' one at Guade- 
loupe by the "Blake", one off Saba by the "Investigator," and 
a part of a stem off Havana by the "Albatross," and only two of 
Holopus rangii, one, a fragment, at Montserrat, and one off 
Cuba, both by the "Blake." The majority of the known speci- 
mens of both these species have been taken on fishermen's lines, 
or by shore parties working from a small boat, or discovered on 
the beaches. 

The apparent rarity of these species, in contrast to the other 
species of Isocrinus, the species of Democrinus and the species of 
Bythocrinus, is undoubtedly due to the fact that they inhabit 
shallow water, living amongst the gorgonians and corals, like the 
similarly rare West Indian astrophytons. 

This hypothesis is supported by the occasional occurrence of 
Holopus rangii washed up on the windward beaches of Bar- 
bados, where it is recorded also that once after a hurricane a 
large number of individuals of Isocrinus of all ages and sizes 
were cast ashore, and by the capture by Sir Rawson Rawson of 
two specimens of Holopus in 5 fathoms of water. 

Speaking of the habitat of Isocrinus Sir Rawson wrote in a 
letter to Dr. Gray: "I have only procured one specimen of the 



BARBADOS-ANTIGUA REPORTS 7 

Pentacrinus caput-medusce [Endoxocrinus parrm], and it was 
the first; I am therefore more uncertain about the place where it 
was procured than I am about the habitat of the Pentacrinus 
mulleri [Isocrinus decorus] . But I believe that they are all pro- 
cured on the same bank, which, instead of five or six miles from 
the shore, as I was first informed, cannot be more than a mile, 
within the hundred-fathom line." 

From this it is apparent that Endoxocrinus parrm and Iso- 
crinus decorus occur in relatively shallow water at Barbados as 
elsewhere in the West Indies. 

THE RESULTS OF THE BARBADOS-ANTIGUA 
EXPEDITION 

While a considerable number of species have been described 
from the Caribbean region our knowledge of the crinoids of that 
area is still in its infancy, and any information of any kind 
regarding them is therefore of interest and value. 

To illustrate the paucity of the data regarding the crinoids 
from the very shallow water in the western Atlantic I may men- 
tion that, except for Tropiometra picta which is locally abundant 
from Tobago, Trinidad, and Venezuela to southern Brazil, there 
are only six records, one from Bahamas (Nemaster iowensis), 
one from the Tortugas, Florida (Nemaster iowensis, discovered 
by the University of Iowa's Bahamas Expedition), one from St. 
Thomas (Antedon diibenii), one from Dominica (Nemaster 
iowensis), and two from Brazil (Antedon diibenii and Nemaster 
sp.). 

We probably already know a majority of the species inhabiting 
the Caribbean region ; but these have been described from speci- 
mens long preserved and without notes regarding the details of 
their occurrence, color, or other points of interest, while in order 
to understand any animal we must have far more information 
than that included in a mere description of its differential struc- 
tural characters and one or two records of its occurrence. 

Considering the relative rarity of littoral and sublittoral cri- 
noids in the Caribbean region and the difficulties attending their 
capture owing to the roughness of the bottom frequented by them 
the collection by the Expedition of representatives of this group 



8 IOWA STUDIES IN NATURAL HISTORY 

at no less than twenty-five out of one hundred and one stations 
constitutes quite a remarkable record. 

The species represented are the following: 

Nemaster iowensis Comactinia meridionalis 

Nemaster discoidea Analcidometra armata 

Leptonemaster venustus Coccometra hagenii 

Democrinus rawsonii 

Of these seven species one, Analcidometra armata, is new to 
the fauna of Barbados, having previously been known only from 
near the Tortugas, Florida, and from off Colon. The record of 
Nemaster discoidea from Antigua is the first record of any cri- 
noid from that island. 

Professor Nutting's notes on the occurrence and color of the 
comatulids at Barbados are very interesting and instructive. 

He says that a as a whole they seemed much more brilliant 
than the forms encountered on the 'Pentaerinus ground' off 
Havana and on the Pourtales plateau by the Bahama expedition. 
Few marine animals are harder to secure intact than these, as 
the very fragile arms are almost sure to be broken in dredging, 
either with the dredge or tangles. We secured a number of per- 
fect specimens by taking them from the crannies in large coral 
rocks brought up from time to time in the dredge. Here they 
had been protected and could be taken out without injury; but 
their colors, alas, soon vanished in preservatives. This habit of 
living in rocks .... was quite the usual thing off Bar- 
bados. We often found these crinoids far in the interior of 
masses of old coral rock brought up in the dredge, and we were 
careful to break such rock very thoroughly, as fine eomatulse 
were often found within a cavity in the very heart of such 
masses. 

"It is hard to imagine the use of these brilliant colors in a 
habitat such as this. Of course the rocks themselves were often 
brilliantly colored by the assemblage of corallines, sponges and 
gorgonians with which they were overgrown. The predominating 
colors of these were red and yellow, which also characterized the 
comatulids as well. I find the following colorations of free 
crinoids mentioned in my notes: ' yellow and white; yellow and 
red; purple and white; black arms, with yellowish pinnules; 



BARBADOS-ANTIGUA REPORTS 9 

rich deep vermillion, with bright yellow pinnules ; lemon yellow, 
with black tipper surface to the arms ; grayish in color ; violet in 
tinge ; a crimson crinoid arm ; black, with greenish yellow arms ; 
magenta, with dark yellowish arms; one specimen very dark 
gray, almost black, with whitish cirri.' " 

The Crinoid Fauna of Barbados 

Crinoids have been dredged by the steamers of the United 
States Coast Survey at the following stations at Barbados: 

"Hassler" Station, December 30, 1871, off Sandy Bay, 100 
fathoms 

Neocomatella pulchella Comactinia echinoptera 

Neocomatella alata Democrinus rawsonii 

"Blake" Station 272, off Barbados, 76 fathoms 
Comactinia meridionalis Crinometra coronata 

"Blake" Station 273, off Barbados, 103 fathoms 
Neocomatella pulchella Democrinus rawsonii 

"Blake" Station 274, off Barbados, 209 fathoms 
Bythocrinus robustus 

"Blake" Station 277, off Barbados, 106 fathoms 
Neocomatella pulchella Comactinia echinoptera 

Neocomatella alata Comactinia meridionalis 

Democrinus rawsonii 

"Blake" Station 278, off Barbados, 69 fathoms 

Comactinia meridionalis 
"Blake" Station 280, off Barbados, 221 fathoms 

Endoxocrinus parrce 
"Blake" Station 281, off Barbados, 200 fathoms 

Isocrinus blakei 
"Blake" Station 283, off Barbados, 237 fathoms 

Endoxocrinus parrce 
"Blake" Station 285, off Barbados, 13-40 fathoms 

Nemaster rubiginosa 



10 IOWA STUDIES IN NATURAL HISTORY 

"Blake" Station 286, off Barbados, 7-45 fathoms 
Comactinia meridionalis 

"Blake" Station 287, off Barbados, 7y 2 ~50 fathoms 
Neocomatella pulchella 

"Blake" Station 290, off Barbados, 73 fathoms 
Neocomatella pulchella Stylometra spinifera 

Democrinus rawsonii 

"Blake" Station 291, off Barbados, 200 fathoms 
Isocrinus blakei Endoxocrinus parrce 

"Blake" Station 292, off Barbados, 56 fathoms 
Stylometra spinifera 

"Blake" Station 294, off Barbados, 137 fathoms 
Neocomatella pulchella Neocomatella alata 

"Blake" Station 295, off Barbados, 180 fathoms 
Isocrinus blakei Endoxocrinus parrce 

"Blake" Station 296, off Barbados, 84 fathoms 
Neocomatella pulchella Endoxocrinus parrce 

Isocrinus decorus Democrinus rawsonii 

"Blake" Station 297, off Barbados, 123 fathoms 
Comactinia meridionalis Stylometra spinifera 

Democrinus rawsonii 

"Blake" Station 298, off Barbados, 120 fathoms 
Neocomatella pulchella Leptonemaster venustus 

Neocomatella alata Stylometra spinifera 

Isocrinus decorus 

"Blake" Station 299, off Barbados, 140 fathoms 
Neocomatella pulchella Stylometra spinifera 

According to P. H. Carpenter Sir Rawson Rawson obtained at 
Barbados the following crinoids: 

Exocyclic comatulids Isocrinus decorus 

Endocyclic comatulids Endoxocrinus parrce 

Holopus rangii 



BARBADOS-ANTIGUA REPORTS 11 

There are in the British Museum the following crinoids from 
Barbados : 

Comactinia echinoptera Endoxocrinus parrm 

Stylometra spinifera Holopus rangii 

The Kiel Museum contains two crinoids from Barbados, col- 
lected in 1873 : 

Nemaster discoidea Comactinia meridionalis 

In the Hamburg Museum there is the following crinoid from 
Barbados : 

Isocrinus decerns 

Thus the known crinoid fauna of Barbados in 1913 included 
the following seventeen species : 

Neocomatella pulchella Crinometra coronata 

Neocomatella alata Coccometra hagenii 

Nemaster rubiginosa Isocrinus asteria 

Nemaster discoidea Isocrinus decorus 

Leptonemaster venustus Isocrinus blakei 

Comactinia echinoptera Endoxocrinus parrm 

Comactinia meridionalis Holopus rangii 

Stylometra spinifera Democrinus rawsonii 
Bythocrinus robustus 

It is interesting that specimens of the following, practically 
half of the total number, had been brought up on fishermen's 
lines or captured in other ways without the assistance of elab- 
orate dredging gear : 

Nemaster discoidea Isocrinus asteria 

Comactinia echinoptera Isocrinus decorus 

Comactinia meridionalis Endoxocrinus parrce 

Stylometra spinifera Holopus rangii 

Indeed, Isocrinus asteria and Holopus rangii have both been 
found washed up on the beaches. 

The West Indian Crfowid Fauna 

There are known from recent seas 576 described species of 
crinoids, representing 142 genera which are distributed among 
28 families and subfamilies; of these, 76 species, included in 22 



12 IOWA STUDIES IN NATURAL HISTORY 

genera and 6 families, are stalked, while 500 species, included in 
120 genera and 22 families and subfamilies, are of the unstalked 
comatulid type. 

In the West Indian region there occur 51 species (exclusive of 
two inadequately described) distributed among 30 genera and 
16 families and subfamilies; of these 12 species belonging to 8 
genera and three families are stalked, and 39 species belonging 
to 22 genera and 12 families and subfamilies are eomatulids. 

It will be remembered that Dr. P. H. Carpenter in 1881, after 
a cursory examination of the " Blake' ' eomatulids estimated the 
number of West Indian species as slightly less than 55. 

The families and subfamilies represented in the West Indian 
region are 

Capillasterinae Perometrinae 

Comactiniinae Zenometrina? 

Colobometridae Bathymetrinae 

Tropiometridae Pentametrocrinidae 

Thalassometridae Atelecrinidae 

Charitometridae Pentacrinidae 

Antedoninae Holopodidae 

Thysanometrinae Bourgueticrinidae 

Of the genera the following 16 are confined to the West Indian 
region, though all of these, excepting Holopus, are closely related 
to Indo-Paeifie genera 

Nemaster Horaeometra 

Leptonemaster Crinometra 

comatonia hybometra 

comatilia coccometra 

mlcrocomatula zenometra 

comactinia hypalometra 

Analcidometra Holopus 

Stylometra Isocrinus 

The following 3 genera occur also in the eastern Atlantic, but 
not in the Indo-Paeific region 

Neocomatella Antedon 

Rhizocrinus 



BARBADOS-ANTIGUA REPORTS 13 

The following 11 genera occur in the Indo-Paeific region as 
well as in the West Indies 

Tropiometra Atelecrinus 

Crotalometra Endoxocrinus 

Adelometra Bathycrinus 

Trichometra Monachocrinus 

Pentametrocrinus Democrinus 

Bythocrinus 

This shows graphically the isolation of the crinoid fauna of 
the Caribbean area. 

The Geological Significame of the West Indian Crinoid Fauna 
Of the six fossil groups which are represented by recent spe- 
cies, the Zygometridae, Pentacrinidae, Holopodidae, Apioerinidae, 
Bourguetierinidae and Plicatocrinidae, three, the Pentacrinidae, 
Holopodidae and Bourgueticrinidae, occur in the West Indian 
region, and the Plieatoerinidae, inhabiting the abysses and known 
from off west Africa, probably will eventually be found there. 

The genera occurring in the West Indies which include both 
recent and fossil species are the following 

Family Pentaerinidae 
Isocrinus 
Range of the recent species. — West Indies. 
Horizons. — Trias and Jurassic ; Europe and North America. 

Family Holopodidae 
Holopus 

Range of the recent species. — West Indies. 
Horizon. — Tertiary; Italy. 

Family Bourgueticrinidae 
Rhizocrinus 
Range of the recent species. — West Indies to Massachusetts, 

and northwestern Europe. 
Horizons. — Cretaceous, New Jersey; Eocene, Europe. 
Democrinus 

Rmge of the recent species. — Tropical Atlantic and East 

Indies. 
Horizon. — Recent; Guadeloupe. 

As in all the rest of the world there are only two genera, 



14 IOWA STUDIES IN NATURAL HISTORY 

Catoptometra and Eudiocrinus, both belonging to the Zygo- 
metridae and both ranging from the Malayan region to southern 
Japan, which are definitely known to include both recent and 
fossil species, it would seem that the Caribbean region has a 
closer affinity with the past faunas than has any other area. 

The relative antiquity of the West Indian crinoid fauna seems 
to be attested by the following facts : 

Of the 8 genera of stalked crinoids represented 4, or one-half, 
occur also as fossils ; in the Indo-Paeific region out of 19 stalked 
genera only 1 occurs as a fossil.* 

Of the 30 genera of comatulids 23, or 77%, include only five or 
ten armed species. The Comasterinae, Himerometridae, 
Stephanometridae and Mariametridae, including only multi- 
brachiate species, are not represented ; the Zygometridae, many 
species of which are conspicuous for the great number of arms, 
is also unrepresented. 

Of these 30 comatulid genera 23, or 77%, are monotypic, or 
are represented by a single species. 

KEY TO THE GENERA OF CRINOIDS REPRESENTED IN THE 
CARIBBEAN SEA AND ADJACENT WATERS 

a 1 No stem; the center of the dorsal side of the animal is occupied by a 
single more or less thick plate or knob bearing jointed appendages by 
means of which the animal attaches itself. 
b 1 five very long and slender arms 

Pentametroerinus 
b2 ten or more arms 

c 1 one or more of the proximal pinnules bears in its terminal por- 
tion a comb-like structure formed by the production of the distal 
outer side of each of the segments in the form of a long thin 
triangular process 
d 1 more than ten arms 

e 1 all of the division series are composed of two ossicles; 
the lowest pinnule is on the second brachial following 
the last axillary 

Neocomatella 
e2 first division series of two ossicles, the second of four of 



*Cf. The Ontogeny of a Genus, American Naturalist, vol. 45, No. 534, June, 1911, 
pp. 372-374; The Comparative Age of the Recent Crinoid Faunas, American Journal 
of Science [4], vol. 32 (whole No. 182), No. 188, August, 1911, pp. 127-132; Das 
relative Alter der rezenten Seelilienfaunen, Naturwiss. Rundschau, JG. 27, No. 15, 
April 11, 1912, pp. 191-192; On the Deep Sea and Comparable Faunas, Intern. 
Revue der ges. Hvdrobiol. und Hydrogr., vol. 6, 1913, Heft 1, pp. 17-30, Heft 2/3, 
pp. 133-146. 



BARBADOS-ANTIGUA REPORTS 15 

which the two outer are united by syzygy, the following 
of three of which the two outer are united by syzygy; 
sometimes the division series are very irregular; the 
first pinnule following the outermost axillaries is on the 
first brachial 

Nemaster 
d 2 ten arms 

ei cirri short and stou* with the dorsal profile smooth, there 
being no processes on the distal ends of the segments; 
the segments of the middle pinnules are short and broad, 
with the distal corners more or less produced 

Comactinia 

e 2 cirri longer and more slender, the outer segments bearing 
more or less prominent processes on the dorsal side of 
the distal ends 

fi the three pairs of pinnules following the first pair 
on each arm are absent 

Comatilia 
f 2 all of the pinnules are present 

gi first and second segments of the proximal pin- 
nules with a very high and prominent carinate 
process of which the outer edge, at least on the 
second segment, is parallel with the longitudinal 
axis of the pinnule 

Leptonemaster 

g2 there are no carinate processes on the basal seg- 
ments of the proximal pinnules 
h 1 cirri slender, but not excessively so; terminal 
comb arising at about, or even within, the 
proximal third of the pinnules of the first 
pair, composed of exceptionally large 
rounded teeth which usually much exceed in 
height the lateral diameter of the segments 
which bear them, and frequently absent; 
4th-7th brachials with prominent spinous 
median knobs or keels; usually one or more 
of the earlier segments of P t is twice as long 
as broad, or even longer; size moderate 

Comatonia 

h2 cirri excessively slender and threadlike, the 
enormously elongated segments with greatly 
swollen articulations; the penultimate seg- 
ment, which is much shorter than those pre- 
ceding, is twice as long as broad; terminal 



16 IOWA STUDIES IN NATURAL HISTORY 

eomb confined to the tip of the proximal 
pinnules, and of the usual type; no carina- 
tion of the earlier brachials; none of the 
segments of P a elongated 

Microcomatula 

c 2 no comb-like structures on the proximal pinnules 

d 1 there are no deposits in the ventral perisome of the pinnules 
visible to the naked eye 

e 1 each cirrus socket is bordered proximally and laterally by 
a prominent raised rim; a narrow circlet of basals sep- 
arates the eentrodorsal from the radials; centrodorsal 
conical, the cirrus sockets arranged in ten equidistant 
columns; first syzygial pair and following brachials very 
obliquely wedge-shaped or triangular 

Atelecrinus 

e 2 no raised rim about the proximal and lateral portions of 
the cirrus sockets; no basals; first syzygial pair oblong; 
following brachials oblong or slightly wedge-shaped, 
later becoming triangular, or at least more obliquely 
wedge-shaped 

f i centrodorsal elongate, conical or columnar, with the 
cirrus sockets arranged in 10 definite columns 
gi the ten columns of eirrus sockets are closely 
crowded on a conical centrodorsal; size small; 
color yellow 

Adelometra 

g 2 the ten columns of cirrus sockets are segregated 
in five radial pairs separated by high inter- 
radial ridges; centrodorsal columnar; size me- 
dium or large; color red or purple 

Zenometra 

f 2 cirrus sockets closely crowded, and without definite 
arrangement 

gi proximal pinnules absent; lowest pinnule on the 
fifth brachial 

Hypalometra 

g 2 proximal pinnules present; the second and fol- 
lowing brachials bear pinnules 
hi first pinnule extraordinarily flexible, com- 
posed of more than 30 segments which are 
about as long as broad with their corners 
cut away, appearing like a string of minute 
beads; second and following pinnules of the 



BARBADOS-ANTIGUA REPORTS 17 

same length, but composed of about half as 
many much longer segments, and much less 
flexible 

Coccometra 

h 2 most or all of the segments of the first pin- 
nule longer than broad 

ii proximal pinnules all of the same char- 
acter; first pinnule shorter than the sec- 
ond, which is shorter than the third 
ji each brachial has the midline of the 
dorsal surface raised into a high 
prominent keel; the division series 
and first two brachials are very 
broad, in close lateral contact with 
their neighbors, and only slightly 
convex dorsally; the genital pinnules 
are very long, the longest pinnules 
on the arm; the centrodorsal is very 
large, columnar or broad truncated 
conical; the cirri are short and stout, 
without dorsal processes; the general 
habitus is stout 

Tropiometra 

j 2 the dorsal surface of the brachials is 
unmodified, but their distal edges are 
produced in a frill of long spines; 
the division series and lower brachials 
are narrow and well rounded dorsal- 
ly; the genital pinnules are shorter 
than the proximal or distal pinnules, 
which are of the same length; all the 
pinnules are very slender and stiff, 
especially the lower, which are thorn- 
like, the component segments with 
numerous long spines on their distal 
ends 

Hybometra 

i2 first pinnule markedly longer than the 
second and following 
ji first pinnule very stout, and so large 
at the base as to give the second 
brachial the appearance of an axil- 
lary; edges of the elements of the 
division series armed with coarse 



18 IOWA STUDIES IN NATURAL HISTORY 

short spines; cirri short and stout, 
with short subequal segments most of 
which bear high dorsal spines, the 
more proximal with a transversely 
elongate chisel-like edge 

Analcidomelra 

j 2 first pinnule much elongated, but not 
especially stout; no true dorsal spines 
on the cirrus segments 
ki centrodorsal rounded conical, al- 
most entirely covered with from 
40 to 60 cirrus sockets; cirri long, 
rather slender, composed of from 
25 to 30 segments; proximal 
brachials with the distal edge ab- 
ruptly everted and conspicuously 
spinous; first pinnule more slen- 
der than those following; division 
series and lower brachials in close 
lateral apposition and flattened 
against their neighbors 

Trichometra 

k2 centrodorsal very low, flattened 
hemispherical, with less than 35 
cirrus sockets; cirri short, rather 
stout, with not more than 15 seg- 
ments; no eversion of the distal 
borders of the earlier brachials; 
first pinnule stouter than those 
succeeding; division series and 
arm bases narrow and widely 
separated; a cluster of perisomic 
interradial plates in each inter- 
radial angle 

Antedcm 

d 2 the ambulacral grooves on the pinnules and arms are bor- 
dered by two rows of minute plates easily seen in dried 
specimens of which those of the inner row can be closed 
down over them 

e 1 cirri short and stout, strongly curved, with not more 
than 20 segments none of which bear dorsal spines; 
centrodorsal very broad, more or less columnar or broad 
truncated conical, the cirrus sockets closely crowded and 
irregularly arranged; first two pinnules similar, slender, 



BARBADOS-ANTIGUA REPORTS 19 

composed of numerous short segments; 20-30 arms; 
proximal portion of animal usually highly ornamented 
with spines or tubercles, though sometimes plain 

Crinometra 

e 2 cirri long, with more than 30 segments of which the out- 
er bear prominent dorsal spines; centrodorsal rather 
small, more or less conical, the cirrus sockets arranged 
in ten columns; first pinnule longer and stouter than the 
following 

fi the segments in the basal half of the genital pin- 
^ nules are much broadened, forming a roof over the 

gonads; 10 arms 

Horaeometra 

fs the segments of the genital pinnules are not ex- 
panded; usually between 20 and 30 arms 
gi very spinous; the edges of the elements of the 
division series and lower brachials are armed 
with long spines, and each of the middle and 
outer brachials bears a single long curved later- 
ally compressed spine which overlaps the base of 
the brachial succeeding; division series and arm 
bases narrow, strong convex dorsally and more 
or less separated 

Stylometra 

g 2 smooth; the edges of the elements of the divi- 
sion series and brachials are unmodified; divi- 
sion series and arm bases broad and in close 
lateral apposition 

Crotalometra 
a 2 A stem is present 

b 1 the short thick stem or stalk consists of a single unjointed element 
by which the animal is solidly attached to corals or other hard ob- 
jects; the arms are very short and stout, six of them being consid- 
erably larger than the other four 

Holopus 

b 2 the stem is long and many jointed; its distal end is never attached 
bearing five articulated processes or cirri; the stem ends ab- 
ruptly, exposing the distal face of one of the columnals, which 
is usually more or less worn; size large 
d 1 all of the division series are of two elements 

Endoxocrinus 

d 2 the first division series is of two elements, the following 
always of more than two, the number increasing distally 

Isocrinus 



20 IOWA STUDIES IN NATURAL HISTORY 

e 2 there are no modified columnals, and no cirri; at the end of the 
stem there is a cluster of roots, or radicular cirri, which may 
extend upward over a number of columnals 
di the third, sixth and ninth brachials (the fifth, eighth and 
eleventh ossicles beyond the radials) have a muscular articu- 
lation at either end; the basals are fused into a solid ring 
which is broader than long, cylindrical or truncated conical 

Bathycrinus 

ds all the ossicles following the radials are united in pairs by 
non-muscular articulations; that is, muscular and non-mus- 
cular articulations regularly alternate throughout the arm; 
the basals are separated, or fused into a solid ring which is 
truncated conical, longer than broad 
e 1 ten arms (twelve arms in six-rayed species) 

Monachocrinus 
e 2 five arms 

f i no sutures visible between the basals, which are fused 
into a solid eonical ossicle; four to seven rays 

Bhisocrinus 

f2 basals always separated by distinct sutures; always 
five rays 

gi stem relatively slender, the longest columnals at 
least twice as long as broad; calyx more or less 
conical 

Bythocrinus 

g 2 stem stout, the longest columnals rarely so much 
as twice as long as broad, usually only slightly 
longer than broad; calyx almost or quite cylin- 
drical 

Democrinus 

THE PLANT-LIKE INTERRELATIONSHIPS OF THE 
CARIBBEAN CRINOIDS 

Some years ago I stated that the study of the fixed and seden- 
tary marine animals was often rendered exceptionally difficult 
through the more or less complete assumption of that type of 
variation which we find among the plants. Individuals of many 
species of plants vary very widely according to the dampness or 
dryness, richness or barrenness, and brightness or darkness of 
the locality inhabited, while in other types which will grow only 
within a relatively small range of conditions the variation is 
slight. 



BARBADOS-ANTIGUA REPORTS 21 

The same thing is true in the fixed and sedentary marine ani- 
mals, and is well illustrated by the Caribbean erinoids. 

The thermal and actinic range of the stalked species is small, 
as they are for the most part inhabitants of deep water where 
conditions are practically uniform; their range of variation is 
therefore slight and there is little difficulty in delimiting their 
species. 

But many, if not most, of the unstalked species in the Carib- 
bean Sea have an unusually great bathymetrical range, their 
representatives in the littoral and sublittoral zones living under 
a great variety of conditions varying in temperature and illumi- 
nation, and therefore also in the quality and quantity of the 
food. From this circumstance it comes about that each of the 
more abundant types occurs in a number of more or less distinct 
varieties which, intergrading in every conceivable way, are quite 
plant-like in their interrelationships, and which appear to be 
proportionate in number to the thermal and actinic range of the 
species. 

Thus the interrelationships of the forms in the genus Comac- 
tinia — Hartlaub recognizes fifteen varieties of Comactinia echin- 
optera — and in the genus Crinometra, with fifteen nominal spe- 
cies, recall the interrelationships of the more difficult sections of 
such plant genera as Crataegus, Rubus or Rosa, and those of the 
forms in the genus Nemaster the interrelationships of our local 
species of Ciroea. 

The comatulids differ from all the other fixed and sedentary 
animals in being reduced to practically nothing but a food col- 
lecting apparatus, the organs not concerned, as are the arms and 
pinnules, in the collection of food being reduced to an absolute 
minimum. In the plants the species of Rafflesiaeeae are for the 
most part reduced to a flower only, without leaves, stem or true 
root, and it is interesting to note that the range in size of the 
species of Rafflesiaeeae and of the comatulids is the same, from 
less than an inch in diameter to about three feet (Bafflesia 
arnoldi and Heliometra maxima) . 

In the erinoids the excretion of waste products is for the most 
part effected by the formation of small globules (sacculi) chiefly 
along the ambulacral grooves which are superficially quite similar 
to the "glands" dotting the leaves in the Hypericaceae and 



22 IOWA STUDIES IN NATURAL HISTORY 

other plants. As a rule in the erinoids, as in many, if not most, 
other sedentary and fixed types, the pigment is more or less dis- 
tributed throughout the entire animal (it may even be chiefly or 
entirely internal in some of the Polyzoa) as in most of the plants 
used for dyeing purposes, and is not chiefly or exclusively super- 
ficial as in most active animals. "When it is recalled that the 
variations in the symmetry of flowers are duplicated with great 
exactness in the zooids of the fixed animal types and in the 
erinoids, the odorous features of the Menthaceae, most Solana- 
eese, etc., are equally characteristic of sponges, the acrid juice of 
the Brassicaeeae is duplicated in most coelenterates (small mille- 
pores are called "sea ginger" in Barbados), the pleasant odor 
of many plants is equally a feature of Flustra and other marine 
animals, etc., etc., the comparison between the fixed and seden- 
tary animals and the plants is seen to be quite justified. 

Annotated List op the Species Obtained 

Family Comasteridae 

Subfamily Capillasterinae 

Nemaster iowensis (Springer) 

Actinometra iowensis 1902. Springer, American Geologist, voL 
30, p. 98 (Florida reefs, 3 feet).— 1903. Springer, Bull. Lab. 
Nat. Hist. State Univ. Iowa, vol. 5, No. 3, pp. 217-221, plate 1. 

Nemaster iowensis 1909. A. H. Clark, Vid. Medd. fra den natur- 
hist. Foren. i Kobenhavn, 1909, p. 118. 
Station 53 : 

Arms only; "arms black, pinnules lemon yellow at tips, shad- 
ing into black/ ' 

Station 97: 
Arms only. 
Station 98 : 
Arms only. 
Station 99 : 
Arms only. 
Station 100 : 
Arms only. 



BARBADOS-ANTIGUA REPORTS 23 

Barbados; Engineers' Pier, in 25 feet of water. 

One specimen ; the eentrodorsal is very thin, discoidal, the flat 
dorsal pole 5 mm. in diameter, slightly sunken in a circular area 
2 mm. in diameter in the center. 

The cirri, which are arranged in a single very irregular mar- 
ginal row, are XXII, 13-15, 13 mm. or 14 mm. long. 

The 43 arms are about 90 mm. long. 

The color in life was "sulphur yellow.' ' 

Barbados. 

Arms only ; * ' nearly black. ' ' 

Nemaster discoidea (P. H. Carpenter) 

Actinometra discoidea 1883. von Graff, Bull. Mus. Comp. 
Zool., vol. 11, No. 7, p. 127 (nomen nudum; myzostomes). — 
1884. von Graff, "■ Challenger" Reports, vol. 10, Zoology, 
part 27, p. 14 (nomen nudum; myzostomes). — 1888. P. H. 
Carpenter, "Challenger" Reports, vol. 26, Zoology, pp. 58, 
316, 317, 368, 382 (Caribbean Islands, 88-118 fathoms). 

Actinometra echinoptera var. discoidea 1912. Hartlub, Mem. 
Mus. Comp. Zool., vol. 27, No. 4, p. 463, pi. 17, figs. 7, 9, 15 
(fig. 14, also given as this species, is probably iowensis). 

Nemaster insolitus 1917. A. H. Clark, Proc. Biol. Soc. Wash- 
ington, vol. 30, p. 65 (" Albatross' ' Station 2146, Caribbean 
Sea, 34 fathoms). 
Station 50: 
Arms only. 
Station 51 : 

One magnificent specimen; the eentrodorsal is thin, discoidal, 
the flat dorsal pole 5 mm. in diameter with a shallow central de- 
pression; the cirri are XXIV, 13, from 12 mm. to 14 mm. long; 
the twenty slender arms are about 150 mm. long ; all of the IIBr 
series are 4(3+4). 

Station 70: 
Arm fragments. 
Station 79 : 
Arms only. 
Station 85 : 
Part of an arm. 



24 IOWA STUDIES IN NATURAL HISTORY 

Station 92: 
Arms only. 
Barbados. 

One small specimen with 15 arms 45 mm. long. The color in 
life was "very dark gray, pinnnles and cirri whitish, the former 
banded with darker." 

Detached arms, presumably from another station. The color 
in life was "black, with yellow pinnules/ ' 

Station 101 : 

One much broken specimen with 19 arms. 

Leptonemaster venustus A. H. Clark 

Leptonemaster venustus 1909. A. H. Clark, Proc. U. S. Nat. 

Mus., vol. 36, p. 499 (" Grampus' ' Station 5104). 

Station 3: 

One small specimen; this had "a greenish tinge when fresh.' ' 

Station 7: 

One small specimen; in life this was "pale yellow." 

Station 11: 

Twenty specimens, with arms from 20 mm. to 50 mm. in 
length; in life these were "yellow." 

Station 13 : 

One small specimen. 

Station 18 : 

One specimen. 

Station 46: 

One specimen with arms about 65 mm. long. The color in life 
is described as follows: "Arms barred with cadmium yellow; the 
base of each arm is of this color up to the main division, and for 
an eighth of an inch or more distal to this point ; beyond this for 
a quarter of an inch, more or less, the usual white color prevails, 
then a yellow bar for three-sixteenths of an inch, again a white 
bar for about the same distance ; beyond this the white prevails, 
the yellow bars being irregularly spaced and one-sixteenth of an 
inch or less in width ; there are from five to seven bars, as a rule, 
on each arm ; the pinnules over each bar tend to be yellowish ; the 
tips of the arms are also yellowish ; the cirri are a paler yellow." 



BARBADOS-ANTIGUA REPORTS 25 

Station 56: 

One specimen with arms about 30 mm. long. 

Station 59: 

One specimen with arms 50 mm. long. The color in life was 
"yellow." 

Station 67: 

Five specimens with arms up to 65 mm. in length. The color 
in life was " brownish.' ' 

Station 78 : 

One small specimen. 

Subfamily Comactiniinae 

Comactinia meridionalis (Agassiz and Agassiz) 
Alecto meridionalis 1865. Agassiz and Agassiz, Seaside Studies 
p. 121, figs. 153, 154 ("A. Agassiz, MS.;" coast of South Caro 
lina). 

Comactinia meridionalis 1909. A. H. Clark, Vid. Med. fra den 

naturhist. Forening i Kobenhavn, 1909, p. 150. 

Station 9 : 

Arms only. In life these were either " light yellow," or "body 
of arm light yellow, the pinnules deep carmine, tipped with yel- 
low in most cases." 

Station 11 : 

Four specimens, with the arms about 60 mm. long. In life 
these had the arms "dark carmine, the pinnules orange with red 
and yellow spots and tipped with yellow;" or the arms were 
"bright purple, the pinnules more so." 

Station 14 : 

One small specimen, with the "base of the pinnules strongly 
purple." 

Station 51 : 

One young specimen with the arms 40 mm. long. 

Station 67 : 

Five specimens with very slender arms up to about 70 mm. in 
length. In life one was "a rich carmine;" another was "rich 
carmine with yellow spots, the pinnules orange yellow." 

Station 78 : 

Two specimens, the larger with the longest arms about 70 mm 
long. 



26 IOWA STUDIES IN NATURAL HISTORY 

Station 85 : 

One specimen with arms about 70 mm. long. 

Station 96: 

Four specimens, the largest with the anterior arms 85 mm. 
and the posterior 47 mm. in length, closely resembling those 
collected by the "Corwin" off French Reef. In life one was 
"dark yellow ;" the others had the "arms dark rose pink, the 
cirri pale yellow, the pinnules pale yellow, banded with burnt 
sienna. ' ' 

Barbados. 

One specimen, which had the "arms deep mauve, and the 
pinnules very pale straw yellow banded with grayish purple." 

Family Colobometridae 

Analcidometra armata (Pourtales) 

Antedon armata 1869. Pourtales, Bull. Mus. Comp. Zool., vol. 
1, No. 11, p. 356 (west of the Tortugas, in 35 fathoms). 

Oligometra caribbea 1908. A. H. Clark, Proc. U. S. Nat. Mus., 
vol. 34, p. 238 (off Colon, in 34 fathoms). 
Station 11 : 
One very small specimen with arms 15 mm. long. 

Family Antedonidae 

Subfamily Thysanometrinae 

Coccometra hagenii (Pourtales) 
Comatula (Alecto) hagenii 1868. Pourtales, Bull. Mus. Comp. 
Zool., vol. 1, No. 6, p. Ill (of Sand Key, Florida, in 100 
fathoms). 

Coccometra hagenii 1908. A. H. Clark, Proc. Biol. Soc. Wash- 
ington, vol. 21, p. 129. 
Station 15: 
Four small and young specimens ; the segments of Pi are much 

longer than usual, probably owing to their small size. 

Family Bourgueticrinidae 

Democrinus rawsonii (Pourtales) 
Bhizocrinus rawsonii 1874. Pourtales, 111. Cat. Mus. Comp. 
Zool., vol. 4, No. 8, p. 27. 



BARBADOS-ANTIGUA REPORTS 



27 



Station 7 : 

One extraordinarily well preserved specimen, agreeing in all 
details with Pourtales' types, which were also from Barbados. 

The total length is 178.7 mm. ; the arms are 19 mm. long, the 
calyx (including the radials) 4.7 mm. long, and the stem, which 
is composed of 58 columnals plus a portion of the root, is 155 
mm. long. 

LIST OF THE STATIONS, WITH THE SPECIES 
REPRESENTED AT EACH 



Station 


3 


Station 


7 


Station 


9 


Station 


11 


Station 


13 


Station 


14 


Station 


15 


Station 


18 


Station 


46 


Station 


50 


Station 


51 


Station 


53 


Station 


56 


Station 


59 


Station 


67 



Station 78 : 



Station 


79 


Station 


85 


Station 


92 


Station 


96 


Station 


97 


Station 


98 



Leptonemaster venustus 
Leptonemaster venustus 
Democrimis rawsonii 
Comactinia meridionalis (arms) 
Leptonemaster venustus 
Comactinia meridionalis 
Analcidometra armata 
Leptonemaster venustus 
Comactinia meridionalis 
Coccometra hagenii 
Leptonemaster venustus 
Leptonemaster venustus 
Nemaster discoidea (arms) 
Nemaster discoidea 
Comactinia meridionalis 
Nemaster iowensis (arms) 
Leptonemaster venustus 
Leptonemaster venustus 
Leptonemaster venustus 
Comactinia meridionalis 
Leptonemaster venustus 
Comactinia meridionalis 
Nemaster discoidea (arms) 
Comactinia meridionalis 
Nemaster discoidea (arms) 
Comactinia meridionalis 
Nemaster iowensis (arms) 
Nemaster iowensis (arms) 



28 IOWA STUDIES IN NATURAL HISTORY 

Station 99: Nemaster iowensis (arms) 

Barbados; Engineers ' Pier, 25 feet: Nemaster iotvensis 

Barbados: Nemaster iowensis (arms) 

Nemaster discoidea 

Comactinia meridionalis 
Station 101 : Nemaster discoidea 



REPORT ON THE OPHIURANS 

Collected by the Barbados-Antigua Expedition from 
the University of Iowa in 1918 

Austin H. Clark 

Curator, Division of Echinoderms, U. S. National Museum 



PREFACE 



By a fortunate combination of circumstances it happened that 
just before and during the early dredging operations of the U. S. 
Coast Survey between 1867 and 1879 (by the steamers "Cor- 
win," "Hassler" and "Blake"), which were the first intensive 
deep sea investigations ever undertaken, interest in the ophiurans 
had reached a pitch of intensity quite comparable to that of the 
revival of the past ten years centering in the Indo-Pacific and 
Antarctic, and new material was studied and described as rap- 
idly as it was obtained. The two authors of those days chiefly 
interested in the West Indian ophiurans were Theodore Lyman 
of Harvard, who studied the ophiurans collected by the ships of 
the Coast Survey, and later those of the "Challenger," and 
Christian F. Liitken of Copenhagen to whom were sent a large 
number of specimens from the Danish West Indies, mostly from 
St. Thomas, collected by A. H. Riise. As many of Riise's speci- 
mens were later also sent to Lyman, the latter was enabled to 
study authentic examples of many of Liitken 's species from the 
original locality. 

The completeness of the early collections and the thoroughness 
and accuracy with which the early authors worked are attested 
by Professor Koehler's report upon the ophiurans secured by the 
"Albatross" in the West Indies (1914) and by Dr. Hubert 
Lyman Clark's memoir on the ophiurans of Porto Rico (1902) 
and catalogue of known ophiurans (1915) in which a negligible 
number of new Caribbean types are described, and almost none 
of the earlier species placed in synonymy. 

*Published with the permission of the Secretary of the Smithsonian Institution. 

29 



30 IOWA STUDIES IN NATURAL HISTORY 

Within the last few years the study of the ophiurans has taken 
on a renewed impetus, and a number of large and important 
memoirs have appeared. A rather unusual feature of this activ- 
ity has been that all of the authors concerned have worked in 
perfect harmony and without a trace of other than the most 
friendly cooperation, with the result that, instead of a mass of 
new and conflicting ideas and testily debated new genera and 
species we have before us today an entirely new classification of 
these animals in its perfected form only two years old yet 
accepted by all the authorities on the subject, and an increase of 
something like 300% in the number of known species, over 400 
having been described by a single author, very few of which it 
has been found necessary to place in the synonymy of older 
forms. 

To the energy and activity of Professor Rene Koehler of Lyons 
we are indebted for the greatest increase in the number of known 
types, and to Professor Hikoshiehiro Matsumoto of Sendai for 
our new classification ; to Dr. Hubert Lyman Clark of Harvard 
we are indebted not only for an important increase in the num- 
ber of known genera and species, second only to that which we 
owe to Professor Kcehler, but also for a magnificent memoir in 
which all of the recently described new species are included, 
assembled under Matsumoto 's revised classification. 

The classification here adopted follows that employed in Dr. 
Clark's memoir except that, with Professors Koehler and Verrill, 
I recognize the family Ophiomycetidae, the genera of which are 
placed by Matsumoto and by H. L. Clark in the Ophiacanthidae. 

The memoirs which should be consulted in connection with the 
present paper are the following: 

Report on the Ophiuroidea Collected by the Bahama Expe- 
dition in 1893. Addison E. Verrill. Bulletin from the Lab- 
oratories of the State University of Iowa, vol. 5, No. 1 (Bul- 
letin of the University of Iowa, N. S., vol. 1, No. 6), September, 
1899, pp. 1-86, plates 1-8. 

A Contribution to the Study of Ophiurans of the U. S. 
National Museum. Rene Kcehler. Bulletin 84, U. S. Nation- 
al Museum, 1914, pp. i-vii, 1-173, plates 1-18. 



BARBADOS-ANTIGUA REPORTS 31 

A New Classification op the Ophiuroidea. Hikoshichiro 
Matsumoto. Proceedings of the Academy of Natural Sciences, 
Philadelphia, 1915 (April 12, 1915), pp. 43-92. 

Catalogue of Recent Ophiurans : based upon the collection of 
the Museum of Comparative Zoology. Hubert Lyman Clark. 
Memoirs of the Museum of Comparative Zoology, vol. 25, No. 
4, December, 1915, pp. 165-376, plates 1-20. 

A Monograph of Japanese Ophiuroidea, arranged according to 
a new 1 Classification. Hikoshichiro Matsumoto. Journal of 
the College of Science, Imperial University of Tokyo, vol. 38, 
Art. 2, March 31, 1917, pp. 1-408, plates 1-7. 

Ophiures [collected by Kiikenthal and Hartmeyer in the West 
Indies, a number at Barbados] . Rene Koehler. Zoologischer 
Jahrbuch, Supplement 11, Heft 3, 1913, pp. 351-380, plates 
20, 21. 

THE CARIBBEAN ECHINODERM FAUNA 

On the basis of the available data it is difficult to make any 
statements of value regarding the subdivisions of the echinoderm 
fauna of the American side of the tropical Atlantic. There is a 
certain homogeneity about it which suggests that it should be 
regarded as a single faunal unit locally modified, as a result of 
diverse ecological conditions, by the partial or complete elimina- 
tion of certain types which results in local changes in the faunal 
balance ; that is to say, the faunal characteristics of any given 
region are more closely dependent upon the size and character 
of the adjacent land mass (features determining the amount and 
kind of food) than they are upon fundamental faunal consid- 
erations. 

The Brazilian section of this fauna includes several character- 
istic types not known elsewhere in the region. Perhaps the most 
striking of these is Paracentrotus gaimardi, which also occurs in 
west Africa. This species appears to be rare and local and it is 
not by any means certain that it does not occur in the next 
section. 

The fauna of the continental shores of the Caribbean region, 
with Trinidad and Tobago, seems, so far as we can tell, to be 



32 IOWA STUDIES IN NATURAL HISTORY 

essentially similar to the Brazilian, minus certain types and plus 
a few others. The most conspicuous of the latter is the littoral 
Thyraster serpentarius, but this is known only from Vera Cruz 
and from off Tampa Bay, Florida (Cat. No. 36995 U. S. National 
Museum). 

The third division, which appears to be merely the preceding 
minus a number of its characteristic types and plus a few which 
possibly are not in reality confined to it, includes the Antillean 
Islands north of Tobago and the Atlantic coast of North America 
to Carolina, some of the species even reaching Cape Cod. This 
division is richest in species in the Greater Antilles and southern 
Florida, and poorest in the southern Lesser Antilles, especially 
on the oceanic island of Barbados. 

THE OPHIURANS COLLECTED BY THE EXPEDITION 

The expedition brought back representatives of forty-three spe- 
cies of ophiurans; of these 26 were found at Barbados only, 14 
were found both at Barbados and at Antigua, and 3 were found 
only at Antigua. 

Of the 40 species collected at Barbados the following 11 were 
there found for the first time : 

Ophiomyxai flaccida Amphiodia planispina 

Astrophytum muricatum Ophiactis savignyi 

Ophioplus tuberculosus Ophiothrix lineata 

Amphiura diducta Ophiothrix pallida 

Amphipholis limbata Ophiomusium sculptum 

Ophiolepis elegans 

The 17 species collected at Antigua constitute new records; 
they were : 

Ophiomyxa flaccida Ophiocoma riisei 

Ophiactis mulleri Ophioderma appressa 

Ophiothrix angulata Ophioderma brevicauda 

Ophiothrix oerstedii Ophioderma cinerea 

Ophiothrix suensonii Ophioderma rubicunda 

Ophionereis reticulata Ophiura acervata 

Ophiocoma echinata Ophiomusium validum 

Ophiocoma pumila Ophiolepis elegans 
Ophiolepis paucispina 



BARBADOS-ANTIGUA REPORTS 33 

THE WEST INDIAN OPHIURAN FAUNA 

There are known from the recent seas 1420 described species 
of ophiurans representing 192 genera which are distributed 
among 13 families. 

In the West Indian region there occur 255 species represent- 
ing 88 genera and all the known families. 

Whereas in the case of the crinoids all the species occurring in 
the Caribbean region are confined to that area, a considerable 
number of the ophiurans occur more or less generally through- 
out the Atlantic basin, or are represented by closely related 
types in the east Atlantic and Mediterranean Sea, and some are 
almost universally distributed. 

As examples of wide ranging forms the following may be 
mentioned. 

Amphipholis squamata, which is found from Norway to the 
Cape of Good Hope, on both sides of the Atlantic, and from 
Australia and New Zealand to Juan Fernandez, California and 
Hawaii. 

Amphiura otteri, occurring on both coasts of the north Atlan- 
tic and in Lower California. 

Ophiactis savignyi, occurring in shallow water in all warm seas. 

Ophiacantha vepratica, found in the West Indies and in Fiji. 

Ophiomusium lymani, occurring everywhere in water of mod- 
erate depth and temperature. 

Ophiomusium planum, found on both coasts of the middle At- 
lantic and in the Indian Ocean. 

Amphiophiura sculptilis, found in the West Indies, the Indian 
Ocean, the East Indies and Japan. 

Asteronyx loveni, found in all northern seas and southward 
to the West Indies, Lower California and Japan. 

The following 21 genera are known from the Caribbean region 
only; those marked with an asterisk (*) are monotypic. 

*Ophiobrachion *Ophioholcus 

Ophiosciasma *Ophioplus 

*Ophiophrixus *Hemieuryale 



34 IOWA STUDIES IN NATURAL HISTORY 

*astrocnida ophiomitra 

*astrophytum *ophiacanthella 

*astrogordius *mlcrophiura 

*astrocyclus *ophioblenna 

*astrocynodus *ophionema 

[ fophiochondrus] *ophiothyreus 

*Ophiochondrella *Amphipholizona 
*Ophiop^pale 

While a number of these genera will undoubtedly eventually 
be found in other parts of the world, still the fact that they 
represent 24% of the total number of genera occurring in the 
West Indies is significant, and the fact that all but three of them, 
or 83%, are monotypic is still more so. 

The existence in the West Indian region of these endemic 
genera indicates that this region constitutes a very marked 
fauna! entity, while the occurrence of so many monotypic genera 
suggests that faunal stability was attained a long while ago; in 
other words that, as compared to the other portions of the 
oceans, faunal evolution has been retarded so that the West 
Indian region may be described as faunally the most ancient 
portion of the recent seas. 

So far as we are able to judge from the geological record, 
taken in connection with the recent fauna, there are two quite 
distinct types of distribution, always, however, more or less 
superimposed, in every homogeneous animal group. 

A newly arisen animal type immediately spreads to the limits 
of its possible distribution, and within the area overrun by it all 
sorts of variants appear which may be considered as of varietal, 
subspecific or specific value. 

Thus a genus or any other homogeneous group represented in 
a given faunal district by a number of closely related types is a 
group of recent origin, or of recent introduction. 

As time passes a number of factors begin to assert themselves, 
internal and external parasitism, economic pressure of great 
numbers of individuals, and economic pressure of competing 
types, which tend to restrict the possible scope of variation and 
to confine the variants within well marked limits which con- 
stantly become narrower and narrower until only a few well 
marked and distinct types remain each of which has now ac- 
quired the status of a monotypic genus. 



BARBADOS-ANTIGUA REPORTS 35 

Thus a group of animals represented in a given region wholly 
or chiefly by a number of very distinct types, or monotypic gen- 
era, has been more or less isolated in that region for a very con- 
siderable period. 

It is interesting to compare the occurrence of the ophiurans in 
the Caribbean region with that of the crinoids. 

Total number of ophiuran families, 13 ; of crinoid families, 28. 

Total number of ophiuran genera, 192 ; of crinoid genera, 142. 

Total number of ophiuran species, 1420 ; of crinoid species, 576. 

Ophiuran families in the West Indies, 13; percent of total, 
100. 

Crinoid families in the West Indies, 16 ; percent of total, 54. 

Ophiuran genera in the West Indies, 88 ; percent of total, 46. 

Crinoid genera in the West Indies, 30; percent of total, 21. 

Ophiuran species in the West Indies, 255 ; percent of total, 18. 

Crinoid species in the West Indies, 51 ; percent of total, 9. 

Endemic ophiuran genera, 21; percent of total in West In- 
dies, 24. 

Endemic crinoid genera, 16; percent of total in West Indies, 
53. 

Monotypic ophiuran genera, 18 ; percent of total in West In- 
dies, 20. 

Monotypic crinoid genera, 11 ; percent of total in West Indies, 
37. 

The recognized families and subfamilies in the recent crinoids 
are in almost all cases better differentiated than the same divi- 
sions among the ophiurans as we understand them now. This 
indicates a phylogenetic advancement of the crinoid over the 
ophiuran fauna whereby the former has become more definitely 
crystallized into well circumscribed types. 

The relationships of the ophiuran and crinoid families, genera 
and species may be analyzed as follows : 

OPHIURANS CRINOIDS 

Number of families 13 28 

Average number of genera per family 16 5 

Average number of species per genus 7 4 



36 IOWA STUDIES IN NATURAL HISTORY 

The greater number of crinoid families indicates that the 
recent crinoid fauna, if not actually older than the recent ophi- 
uran fauna, at least developed earlier, as the various forms have 
become more definitely circumscribed and segregated into well 
differentiated units. The relative state of undevelopment of the 
ophiuran fauna is also indicated by the much larger number of 
genera in each family and of species in each genus, as well as by 
the larger number of species in each genus in any given locality. 

Only about one-half of the higher groups of crinoids are repre- 
sented in the West Indies, while all of the higher groups of 
ophiurans occur there. One crinoid family, the Holopodidae, is 
known only from the Caribbean Sea. Assuming that the Ma- 
layan region is the present center of distribution for marine 
animals and the place of origin of most recent types, this is 
easily accounted for by the much greater facilities for dispersal 
possessed by the vast majority of the ophiurans, through their 
pelagic young. 

Only 21% of the known crinoid genera are found in the West 
Indies, while 46%, or more than twice as many, of the ophiuran 
genera occur there. This also is probably due to the greater 
facilities for dispersal possessed by the ophiurans. 

Of the known ophiuran species 18% occur in the West Indies, 
as against 9%, half as many, of the known crinoids. This would 
seem to indicate that as the Caribbean crinoid fauna had grown 
old and become crystallized along definite lines no new acces- 
sions had come in from the rapidly developing fauna of the 
Malayan region, whereas the interchange of ophiurans from east 
to west has kept the ophiuran fauna younger. 

Among the crinoids 53% of the Caribbean genera are not 
represented elsewhere, while among the ophiurans the number is 
less than half as large, only 24%. This is the result of the 
crystallization of the West Indian crinoid fauna and the lack of 
interchange with other faunas, which has taken place to a much 
greater degree than in the case of the ophiurans. 

Exactly the same explanation holds for the fact that 37% of 
the endemic genera of crinoids are monotypic, while only about 
half as many of the ophiuran genera, 20%, are monotypic. 

The 192 genera of ophiurans may be classified according to 
their geographical ranges as follows: 



BARBADOS-ANTIGUA REPORTS 37 

Universally distributed, or occurring in all warm seas . . 68 

Indo-Malayan region only 57 

Caribbean region only. . . , 21 

Antarctic only 8 

South Australia, Tasmania and New Zealand 7 

Arctic and north Atlantic 6 

North Pacific 5 

North Pacific and north Atlantic 3 

Middle Atlantic 3 

Caribbean Sea and west coast of Central America 3 

Peru to southern California 3 

Caribbean Sea to Galapagos Islands * 1 

Caribbean Sea and Mediterranean 1 

Indo-Pacific and Mediterranean 1 

Southern California and New Zealand 1 

[Unclassified 4] 

In order fully to understand the affinities of the West Indian 
ophiuran fauna the following apparently anomalous ranges of 
certain genera, supplemented by similar cases among the star- 
fishes and echinoids, must be considered. 

Warmer parts of the eastern and western Atlantic; Mexico 
to Chile 

Narcissia Arbacia 

Both coasts of tropical America 

Encope Mellita 

West Indies and western coast of Central America 

Hemipholis Ophiocryptus 

Ophiozona 

West Indies and Galapagos Islands (probably in reality the 
same as the preceding) 

SlGSBEIA 

Peru to southern California (some only in part) 

Astrocaneum Paulia (Galapagos Islands 

DlOPEDERMA also) 

Gymnophiura Pharia 

Platasterias Phataria 



38 IOWA STUDIES IN NATURAL HISTORY 

Nidorellia CLenocentrotus (Galapagos 

Heliaster Islands also) 

Amphiaster Tetrapygus 

West Indies and eastern Atlantic ; Hawaiian Islands ; southern 
Japan ; Kei Islands 

CLenopedina 

Western coast of Mexico; Hawaiian Islands; Australia, Tas- 
mania and Lord Howe Island; Mediterranean Sea and eastern 
Atlantic 

Centrostephanus 

Southern and Lower California, southern Japan, and south- 
ern Australia 

Heliocidaris 

West Indies and the Hawaiian Islands 

Podocidaris 

West Indies and southern Australia 

Ophioprium 

Southern California and New Zealand 

Ophiopteris 

In view of the past intercommunication between the Caribbean 
Sea and the Pacific the similarity of certain elements of the 
Caribbean fauna and of that of the western coast of tropical 
America is not surprising; the latter, however, includes a very- 
considerable number of genera which occur nowhere else, to- 
gether with a few species of characteristic Indo-Malayan types, 
such as Mithrodia, Acanthaster, Anthenea, Leiaster, Astropyga, 
etc., which are not represented in the Caribbean Sea. 

A significantly large number of genera, including well known 
and conspicuous littoral types, inhabit a more or less extensive 
portion of the following anomalous range — Mediterranean Sea, 
Caribbean Sea, southern Australia and New Zealand, southern 
Japan, the Hawaiian Islands, and the western coast of tropical 
America. 

This discontinuous range, though indicated by very diverse 
types and only in part by each, nevertheless must be considered 
a zoogeographie unit. Its outstanding feature is the fact that it 



BARBADOS-ANTIGUA REPORTS 39 

represents the extreme outer limits of a tropical and subtropical 
f aunal region the center of which is the Indo-Malayan region. 

The types inhabiting it, that is to say occurring only on the 
extreme periphery of the Indo-Pacific f aunal area (of which the 
Mediterranean Sea was at one time a part) may be considered, 
therefore, as relics of a previous fauna at one time characteristic 
of the central Indo-Malayan region from which they have now 
been extirpated through the competition of younger and more 
efficient types. 

The same facts are brought out equally well in many other 
groups of marine animals, and are also reflected in a modified 
way in the terrestrial faunas. 

In the faunas of the colder seas all intergradations are found 
between types which are quite unique, and types differing little 
or not at all from others in the Indo-Malayan region, and this 
intergradation is complete enough so that we are justified in 
considering the fauna of the colder waters as similarly ultimately 
derived from the (past or present) fauna of the East Indian 
region largely through the intermediary of deep water forms. 
Some of these genera of the colder waters, as Astbiclypeus and 
Glyptocidaris, are extraordinarily restricted in their distribu- 
tion and rare, while others are abundant and widely spread. 

One of the peculiarities of the West Indian ophiuran fauna is 
the relatively poor representation of Ophiotrichidae. This family 
includes 13 genera and 157 species of which 126 belong to the 
genus Ophiothbix, occurring in all the warmer portions of the 
recent seas and represented by 7 species in the West Indies. One 
monotypic genus, Ophiotrichoides, is only known from the Cape 
Verde Islands, but the remaining 11 genera are exclusively 
Indo-Malayan. All of the species of this family are more or less 
conmmensal in habit, and some are almost parasitic. The species 
of four of the genera, Ophiomaza, Ophio^ethiops, Ophiophthi- 
rius and Ophiospelera, live upon comatulids. In one genus, 
Ophiopteron, the arm spines are webbed together and resemble 
little fins which has given rise to the idea that it is able to swim. 

The greatest mystery connected with the Caribbean ophiurans 
concerns the genus Ophioblenna. The only known species, 
Ophioblenna antillensis, was described in 1859 from two speci- 
mens collected at Water Island, St. Thomas. In spite of all the 



40 IOWA STUDIES IN NATURAL HISTORY 

collecting that has since been done in the West Indies, and even 
at Water Island itself, no others have ever come to light. 

THE OPHIURANS OF THE CARIBBEAN REGION 

Those designated with an asterisk (*) have been recorded 
from Barbados. 

Family Ophiomyxidae 

Ophiomyxa flaccida Ophiosciasma attenuatum 

*Ophiomyxa tumida Ophiophrixus quadrispinosus 

Ophiomyxa brevicauda Ophiodera stimpsonii 

*Ophiobyrsa serpens Ophioscolex disacanthus 

Ophiobyrsa perrieri ^Ophioscolex glacialis 

Ophiobrachion uncinatus ^Ophioscolex tropicus 
*Ophiogeron supinus Ophioscolex serratus 

* Ophiosciasma granulatum Ophioleptoplax atlantica 

Family Trichasteridae 

m Astroschema arenosum Astroschema elongatum 

Astroschema intectum Astroschema nuttingi 

Astroschema brachiatum Astroschema vicinum 

^Astroschema Iceve *Ophiocreas lumbricus 

* Astroschema oligactes Ophiocreas oedipus 

Astroschema sulcatum *Ophiocreas spinulosum 

^Astroschema tenue Asteronyx loveni 

Astroschema clavigerum Astrodia tenuispina 

Family Gorgonocephalidae 

Astrogomphus vallatus Astrospartus mucronatus 

Astrogomphus rudis Astrophytum muricatum 

* Aster opor pa annulata Astrogordius cacaoticus 
*Asteroporpa pulchra *Astrocyclus concilia 
*Astrocnida isidis Astrocynodus herrarai 

Family Hemieuryalidae 

Ophiochondrus armatus Ophiochondrella squamosa 

* Ophiochondrus convolutus *Sigsbeia murrhina 
Ophiochondrus crassispinus Ophioholcus sexradiatus 
Ophiochondrus gracilis Ophioplus tuberculosus 

*Hemieuryale pustulata 



BARBADOS-ANTIGUA REPORTS 



41 



Family Ophiacanthidae 



Ophiolebes claviger 

Ophiolebes humilis 

Ophiacantha anomala 
^Ophiacantha aspera 

Ophiacantha bidentata 

Ophiacantha cosmica 

Ophiacantha curima 

Ophiacantha echinulata 
^Ophiacantha hirsuta 

Ophiacantha lineata 
^Ophiacantha mesembria 
^Ophiacantha metallacta 

Ophiacantha oligacantha 

Ophiacantha ophiactoides 
*Ophiaoantha pentacrinus 

Ophiacantha robusta 
^Ophiacantha scutata 
^Ophiacantha stellata 
^Ophiacantha valenciennesi 

Ophiacantha affinis 

Ophiacantha levis 

Ophiacantha segesta 

Ophiacantha vepratica 

Ophiothamnus chariis 
^Ophiothamnus exiguus 

Ophiothamnus vicarius 

Ophiologimus 



Ophiomitrella Icevipellis 
Ophiomitrella glabra 

*Ophiomitra valida 
Ophiomitra ornata 

^Ophioplinthaca incisa 
Ophioplinthaca chelys 
Ophioplinthaca dipsacos 
Ophioplinthaca spinissima 

*Ophiocamax fasciculata 

*Ophiocamax hystrix 
Ophiocamax austera 

*Ophiacanthella troscheli 
Ophioprium cervicorne 
Ophioprium imperfectum 
Ophioprium permixtum 
Ophiotreta lineolata 
Ophiotreta mixta 

^Ophiotreta sertata 
Ophiotreta littoralis 
Ophialccea nuttingi 
Ophiotoma bartletti 
Ophiotoma gracilis 
Ophioconis miliaria 

*Ophiohelus umbella 
Microphiura decipiens 
Ophioblenna antillensis 

secundus 



Family Ophiomycetidae 

*Ophioniyces frutectosus Ophiomyces mirabilis 

Ophiotholia mitrephora 

Family Amphiuridae 



* Amphiura goniodes 
Amphiura grandisquamata 
Amphiura lunaris 
Amphiura otteri 
Amphiura hinbergiensis 



Ophiochytra tenuis 
Amphiodia atra 
Amphiodia gyraspis 
Amphiodia limbata 
Amphiodia planispina 



42 



IOWA STUDIES IN NATURAL HISTORY 



* Amphiura palmeri 
Amphiura semiermis 

*Amphiura stimpsonii 
Amphiura bihamula 
Amphiura complanata 
Amphiura crassipes 
Amphiura diducta 
Amphiura fibulata 
Amphiura flexuosa 
Amphiura Jciikenthali 
Amphiura rathbuni 
Amphiura vivipara 
Hemipholis elongata 
Ophiophragmus brachyactis 
Ophiophragmus pulcher 
Ophiophragmus liltkeni 
Ophiophragmus wiirdemanni 
Ophiophragmus filogranea 
Ophiophragmus septa 
Ophionephthys limicola 
Ophionema intricata 
Amphipholis abnormis 
Amphipholis gracillima 
Amphipholis pachybactra 
Amphipholis pentacantha 
Amphipolis squamata 
Amphipolis subtilis 
Ophiostigma isacanthum 

Ophiactis 



Amphiodia pulchella 
Amphiodia repens 
Amphiodia rhabdota 
Amphiodia riisei 
Amphiodia trychna 
Amphiodia lutkeni 
Amphiodia tymbara 
Ophiocnida loveni 
Ophioonida scabriuscula 
Ophiocnida cubana 
Ophiocnida scabra 
Amphioplus abditus 
Amphioplus agassizii 
Amphioplus coniortodes 
Amphioplus cuneata 
Amphioplus incisa 
Amphioplus nereis 
Amphioplus thrombodes 
Amphioplus tumida 
Amphioplus verrilli 
Amphilimna olivacea 
Amphilimna caribea 
Ophiactis cyanosticta 

*Ophiactis duplicata 

*Ophiactis miilleri 
Ophiactis plana 
Ophiactis savignyi 
Ophiactis lymani 
loricata 



Family Ophiotrichidae 

*Ophiothrix angulata Ophiothrix lineata 

Ophiothrix angulata megal- ^Ophiothrix oerstedii 

aspis Ophiothrix pallida 

Ophiothrix brachyactis ^Ophiothrix suensonii 

Ophiothrix rathbuni 

Family Ophiochitonidae 

Ophiochiton grandis *Ophionereis reticulata 



BARBADOS-ANTIGUA REPORTS 



43 



*Ophioplax ljungmani 
Ophioplax reductai 



Ophionereis olivacea 
Ophionereis squamulosa 



Family Ophiocomidae 

*Ophiocoma echinata *Ophiopsila hartmeyeri 

*Ophiocoma pumila ^Ophiopsila polysticta 

*Ophiocoma riisei ^Ophiopsila riisei 

Ophiopsila fulva Ophiopsila maculata 

Ophiopsila vittata 

Family Ophiodermatidae 



^Ophioderma appressa 


Ophioderma rubicunda 


^Ophioderma brevicauda 


Ophioderma pallidum 


*Ophioderma brevispina 


Ophiomusium rugosum 


^Ophioderma cinerea 


Ophioderma squamosissima 


Ophioderma elaps 


Ophiocryptus dubius 


Ophioderma guttatum 


Ophiarachnella angulata 


Ophioderma holmesi 


Ophiarachnella petersi 


^Ophioderma januarii 


Bathypectinura lacertosa 


Ophioderma clypeata 


Bathypectinura tessellata 



Family Ophiolepididae 



*Ophiomastus secundus 
Amphiophiura bullata 

1 Amphiophiura convexa 
Amphiophiura coronata 
Amphiophiura fasciculate 
Amphiophiura metabula 
Amphiophiura oedignatha 
Amphiophiura sculptilis 
Amphiophiura scutata 
Stegophiura macrarthra 

*Ophiura acervata 

*Ophiura falcifera 
Ophiura irrorata 
Ophiura lepida 
Ophiura ljungmani 
Ophiura tenera 

lOphioglyphina robusta 



Ophiomusium planum 
Ophiomusium dugosum 
^Ophiomusium serratum 
^Ophiomusium testudo 
^Ophiomusium validum 
Ophiomusium sculptum 
Ophiomusium stellatum 
Ophiomisidium speciosum 
Ophiomisidium pulchellum 
Ophiolipus agassizii 
Ophiophyllum petilum 
Ophiothyreus go'esii 
* Amphipholizona delicta 
*Ophioceramis albida 
*Ophioceramis januarii 
*Ophiozona impressa 
*Ophiozonella antillarum 



44 IOWA STUDIES IN NATURAL HISTORY 

Homalophiura abyssorum Ophiozonella clypeata 

Homalophiura inornata * Ophiozonella marmorea 

* Ophiomusium aeuferum * Ophiozonella nivea 

Ophiomusium armigerum Ophiozonella nivea compta 

^Ophiomusium eburneum ^Ophiozonella tessellata 

Ophiomusium lymani Ophiomidas dubius 

^Ophiomusium monoplax Ophiolepis elegans 

Ophiomusium oligoplacum *Ophiolepis paucispina 

Family Ophioleucidae 

Ophipleuce depressa Ophiopyren longispinus 

*Ophiopcepale go'esiana *Ophiernus adspersus 

The following names are based upon color varieties: 

Amphiura vivipara var. annulata H. L. Clark 
Ophiothrix oerstedii var. lutea H. L. Clark 
Ophiothrix angulata var. atrolineata H. L. Clark 
Ophiothrix angulata var. violacea Muller and Troschel 
Ophiothrix angulata var. phoinissa H. L. Clark 
Ophiothrix angulata var. phlogina H. L. Clark 
Ophiothrix angulata var. poecila H. L. Clark 

THE OCCURRENCE OF OPHIURANS AT BARBADOS 
AND AT ANTIGUA 

In his account of the natural history of Barbados published in 
1750 the Reverend Griffith Hughes wrote under the heading 
"The Sea Scorpion," "What we call here the Scorpion is by 
Petiver called Stella marina Scolopendroides. Its five rays 
might perhaps properly cause it to be called the Stella marina." 
This is the only ophiuran mentioned by Hughes. 

The Sea Scorpion, Ophiocoma echinata, still called by the same 
name, I found to be abundant in 1903, and Professor Nutting 
states that it occurs almost literally under every stone and scut- 
tles away with amazing celerity when disturbed. It was the 
most abundant and conspicuous form of animal life under the 
loose coral rocks uncovered at low tide on both sides of the labor- 
atory at Pelican Island. It is most commonly brown in color, 
with the club shaped spines almost black. The disk shows great 
variation, often having a central oval or pentagonal area of 



BARBADOS-ANTIGUA REPORTS 45 

cream color showing in sharp contrast to the dark brown spines. 
Besides Ophiocoma echinata, 0. riisei and 0. pumila were se- 
cured, but were much less abundant. Professor Nutting also 
mentions the common association of Ophiocoma echinata with 
Echinometra viridis. 

The species of Ophiocoma were the most common ophiurans 
along the shores at Barbados, although several other species were 
more or less abundant. 

Three species of Ophiothrix, 0. angulata, O. oerstedii and O. 
suensonii, the last named the most abundant, fairly swarmed 
oyer some of the gorgonians brought up near Hastings by the 
diver. Often the large profusely branched gorgonians were 
fairly covered with the wriggling ophiurans. 

Professor Nutting writes that one of the most beautiful ser- 
pent stars he ever saw was taken at Station 64, in from 60 to 70 
fathoms. It was a large specimen with a spread of about ten 
inches, with a very distinct band of vivid crimson on a back- 
ground of light pink along the dorsal surface of the arms and 
extending to the center of the disk. The spines were very slen- 
der, 8 mm. long, quite transparent, with saw-like sides and in 
three series on each side of the arms. This individual has not 
come to hand, but undoubtedly it was a particularly fine example 
of Ophiothrix suensonii. 

Of the simple armed basket fish Professor Nutting says that 
perhaps the most conspicuous and strikingly marked were Aster- 
oporpa and Astrocnida from deep water. The arms in Astero- 
porpa are unbranched, while those of Astrocnida from Stations 
55, in — fathoms, and 89, in 80 fathoms, are slightly branched at 
the tip and ornamented throughout with transverse elevated 
bands of light gray alternating with depressed bands of deep 
chocolate. These circular ridges are beset with thorny stubby 
spines. The bases of the arms are swollen, and the swellings in- 
vade the dorsal surface of the disk in the center of which is a 
star shaped area formed by similar ridges. Another simple 
armed basket fish, Astroschema oligactes, is from Station 7, and 
is orange colored and exceedingly hispid all over, feeling like 
coarse sandpaper, wiry in texture, with arms tapering to a mere 
coiled thread which can wind itself closely around a support and 
cling there most tenaciously. A certain flabellate red and white 



46 IOWA STUDIES IN NATURAL HISTORY 

gorgonian was very common in the dredging and almost always 
a species of simple armed basket fish (Astroschema, spp.) was 
coiled closely around the branches which it matched so perfectly 
in color that it was very apt to be overlooked. The protective 
coloration is so commonly found in serpent stars living as sym- 
bionts on alcyonarians that many writers have noticed it. 

Professor Nutting says that at Antigua "our favorite collect- 
ing ground was near what we called ' Rocky Point/ across from 
Barclay Point and inside of the Pillars of Hercules. . ... 
The echinoderms were perhaps the most conspicuous group at 
this place, although most of the species were the same as those 
secured at Barbados. At the foot of the Pillars of Hercules 
certain species found a refuge in the cracks of the rocks that 
were continually being scoured by the waves. On these rocky 
flats everything seemed to be stuck tight and had to be forcibly 
pried loose. There were small holothurians that wedged them- 
selves in these cracks and held on with remarkable tenacity. ' ' 

OPHIURANS PREVIOUSLY OBTAINED AT BARBADOS 

The Ophiurans collected by the "Hassler" at Barbados in 
100 fathoms 

Astroschema oligactes Ophiothrix angulata 

Astroschema tenuis Ophiothrix suensonii 

Asteroporpa annulata Ophioplax ljungmani 

Astrocnida isidis Ophiura acervata 

Ophiacantha hirsuta Ophiomusium acuferum 

Ophiacantha stellata Ophiomusium testudo 

Ophiomitra valida Ophioceramis albida 

Amphiura palmeri Ophioceramis januarii 

Ophiomyces frutectosus Ophiozonella nivea 

Ophiactis duplicata Ophiopcepale goesiana 

The Ophiurans collected at Barbados by the "Blake" 
Station 272 ; 76 fathoms 

Ophiomyxa tumida Ophiactis mulleri 

Astroschema Iceve Ophiothrix suensonii 

Astroschema oligactes Ophiomusium acuferum 

Asteroporpa annulata Ophiomusium testudo 



y 



BARBADOS-ANTIGUA REPORTS 47 

Ophiomitra valida Amphipholizona delicata 

Ophiactis duplicate, Ophiozona impressa 

Ophiopcepale goesiana 

Station 273; 103 fathoms 

Ophioscolex tropicus Ophioplax ljungmani 

Astroschema Iceve Ophiomusium acuferum 

Asteroporpa annulata Ophiomusium testudo 

Ophiacantha hirsuta Amphipholizona delicata 

Ophiacantha stellata Ophiozonella marmorea 

Ophiactis duplicata Ophiozonella nivea 
Ophiozonella tessellata 

Station 274; 209 fathoms 

Ophiocamax hystrix Ophiomusium acuferum 

Ophiotreta sertata Ophiomusium eburneum 

Ophiactis duplicata Ophiomusium serratum 

Ophiozonella nivea 

Station 275 ; 218 fathoms 

Ophiactis duplicata 

Station 276; 94 fathoms 

Ophiomyxa tumida Ophiactis duplicata 

Astroschema Iceve Ophiothrix suensonii 

Astroschema oligactes Ophionereis reticulata 

Astroschema tenue Ophiomusium acuferum 

Asteroporpa annulata Ophiomusium testudo 

Hemieuryale pustulata Ophiozona impressa 
Ophiozonella antillarum 

Station 277; 106 fathoms 

Asteroporpa annulata Ophiomitra valida 

Sigsbeia murrhina Ophiothrix suensonii 

Hemieuryale pustulata Ophioplax ljungmani 

Ophiomusium acuferum 

Station 278 ; 69 fathoms 

Ophiomyxa tumida Ophionereis reticulata 

Ophiobyrsa serpens Ophioderma cinerea 



48 IOWA STUDIES IN NATURAL HISTORY 

Astroschema oligactes Ophiomusium acuferum 

Amphiura stimpsonii Ophiomusium testudo 

Ophiactis mulleri Ophiozona impressa 

Station 279 ; 118 fathoms 

Ophiocreas spinidosum 

Station 280; 221 fathoms 

Ophiochondrus convolutus Ophiotreta sertata 

Ophiacantha pentacrinus Ophiomusium eburneum 

Ophiocamax hystrix Ophiomusium serratum 

Ophiozonella nivea 

Station 281 ; 288 fathoms 

Ophiomyxa tumida Ophiacantha scutata 

Astroschema arenosum Ophiomyces frutectosus 

Ophiocreas lumbricus Amphiophiura fasciculata 

Ophiocreas spinulosum Ophiomusium acuferum 

Station 282; 154 fathoms 

Ophiomyces frutectosus Ophiozonella tessellata 

Station 283; 237 fathoms 

Ophiacantha aspera Ophiacantha valenciennesi 

Ophiomitra valida 

Station 285 ; 13-40 fathoms 

Ophiomyxa tumida Ophiothrix suensonii 

Ophiothrix angulata Ophiopsila riisei 

Ophioderma brevispina 

Station 286 ; 7-45 fathoms 

Ophiothrix suensonii 

Station 287 ; 7y 2 -50 fathoms 

Ophiopsila polysticta 

Station 288 ; 399 fathoms 

Ophiacantha metallacta Ophiomastus secundus 

Ophiacantha pentacrinus Ophiomusium monoplax 

Ophioplinthaca incisa Ophiozonella antillarum 

Amphiura goniodes Ophiernus adspersus 



BARBADOS-ANTIGUA REPORTS 



49 



Station 290; 73 fathoms 

Ophiomyxa tumida 
Astroschema Iceve 
Astroschema oligactes 
Asteroporpa annulata 
Astrocnida isidis 
Astrocyclus ccecilia 
Ophiacantha aspera 

Ophiozonella 

Station 291; 200 fathoms 
Ophiomyxa tumida 
Ophiogeron supinus 
Ophiacantha pentacrinus 
Ophiacantha scutata 
Ophiocamax hystrix 
Ophiotreta sertata 
Station 292; 56 fathoms 
Astroschema Iceve 
Asteroporpa annulata 
Astrocnida isidis 
Ophiacantha stellata 
Station 293 ; 82 fathoms 
Ophioscolex glacialis 
Ophiacantha hirsuta 
Ophiacantha stellata 

Ophiopcepale 

Station 294; 137 fathoms 
Ophiothrix suensonii 



Ophiacantha stellata 
Ophiomitra valida 
Ophiocanthella troscheli 
Ophiactis duplicata 
Ophiothrix suensonii 
Ophiomusium acuferum 
Ophiomusium testudo 
tessellata 



Ophiura falcifera 
Ophiomusium acuferum 
Ophiomusium validum 
Ophiozonella antillarum 
Ophiozonella nivea 
Ophiernus adspersus 

Ophiothrix angulata 
Ophiothrix suensonii 
Ophiomusium acuferum 
Ophiozonella nivea 

Ophiothrix suensonii 
Ophiomusium acuferum 
Amphipholizona delicata 
go'esiana 



Ophiozonella nivea 



Station 295 ; 180 fathoms 

Ophiocamax fasciculata 

Station 296; 84 fathoms 
Ophiomyxa tumida 
Astroschema Iceve 
Astroschema oligactes 
Asteroporpa annulata 
Astrocnida isidis 



Astrocyclus ccecilia 
Hemieuryale pustulata 
Ophiothamnus exiguus 
Ophiomitra valida 
Ophiomusium acuferum 



50 IOWA STUDIES IN NATURAL HISTORY 

Station 297 ; 123 fathoms 

Astroschema oligactes Ophioplax ljungmani 

Aster oporpa annulata Ophiomusium acuferum 

Ophiomitra valida Ophiozonella tessettata 

Ophiotreta sertata Ophiopcepale goesiana 

Station 298; 120 fathoms 

Astroschema oligactes Astrocnida isidis 

Asteroporpa annulata Ophiopwpale goesiana 

Ophiozona impressa 

Station 299 ; 140 fathoms 

Ophiacantha pentacrinus Ophiomusium acuferum 

Ophiozonella tessellata 

Station 300 ; 82 fathoms 

Ophiacantha hirsuta Ophiohelas umbella 

Ophiomusium acuferum 

Ophiuran recorded as in Sir Rawson W. Rawson's collection: 
Astrocyclus ccecilia 

Ophiurans recorded from Barbados by Professor Rene Koehler 
in 1907: 

Ophioplax ljungmani Ophioscolex glacialis; 

Astrocyclus ccecilia 82 fathoms 

Ophiurans recorded from Barbados by Professor Koehler in 
1913: 

Ophioderma appressa Ophiocoma echinata 

Ophioderma brevicauda Ophiocoma riisei 

Ophioderma cinerea Ophiocoma pumila 

Ophiozona impressa Ophiothrix angulata 

Ophiolepis paucispina Ophiothrix oerstedii 

Ophionereis reticulata Ophiothrix suensonii 

Ophiurans recorded from Barbados by Professor Koehler in 
1914: 

Ophioplax ljungmani Astrocyclus ccecilia 



BARBADOS-ANTIGUA REPORTS 51 

Ophiurans recorded from Barbados by Dr. Hubert Lyman 
Clark in 1915: 

Ophiosciasma granulatum, 94 f ms. 
Asteroporpa pulchra, 56-125 fms. 
Ophiacantha mesembria, 140-221 fms. 
Amphiura palmeri, 100 fms. 
Ophiopsila polysticta, iy 2 ~50 fms. 
Ophiopsila hartmeyeri, 69 fms. 
Amphipholizona delicata, 76-103 fms. 
Ophiomusium monoplax, 399 fms. 
Ophiozonella marmorea, 103 fms. 

ANNOTATED LIST OF THE SPECIES OBTAINED 

Ophiurans collected by the Barbados- Antigua Expedition from 
the State University of Iowa, together with the collecting sta- 
tions listed by the Expedition: 

ANNOTATED LIST OF THE SPECIES OBTAINED 
Order PHRYNOPHIURIDA 

Family Ophiomyxidae 

Ophiomyxa flaccida (Say) 

Pelican Island, Barbados; tide pools. — One specimen. 
English Harbour, Antigua. — One specimen. 

Ophiosciasma granulatum Lyman 
Station 26 : One specimen. 

Family Trichasteridae 

Astroschema arenosum Lyman 
Station 46: Two specimens. 

Astroschema laeve Lyman 
Station 36 : One specimen. 

Astroschema oligactes Liitken 

Station 7 : Five specimens. 
Station 34 : One specimen. 
Station 35 : One specimen. 



52 IOWA STUDIES IN NATURAL HISTORY 

Astrochema tenue Lyman 
Station 59 : part of an arm. 

Family Gorgonocephalidae 

Aster oporpa annulata Liitken 
Station 7 : One specimen. 
Station 41 : One small specimen. 
Station 58 : One small specimen. 

Astrocnida isidis Lyman 
Station 55 : One specimen. 

Astrophytum muricatum (Lamarck) 
Carlisle Bay, Barbados; 20 feet; found on a gorgonian. — One 
small specimen with the disc 14 mm. in diameter. 

Carlisle Bay, Barbados ; 5 fathoms. — One small specimen with 
the disc 12 mm. in diameter. 

Barbados; from fish pots. — Two specimens, one with the disc 
about 50 mm., the other with the disc 30 mm. in diameter. 

Astrocyclus ccecilia (Liitken) 
Station 97: One small specimen with the disc 8 mm. in 
diameter. 

Order L^MOPHIURIDA 
Family Hemieuryalidae 

Sigsbeia murrhinu Lyman 
Station 97 : Four very small specimens, the largest with the 
disc 4 mm. in diameter. 

Ophioplus tuberculosa (Lyman) 
Barbados. — One specimen. 

Hemieuryale pustulata von Martens 
Station 2 : Two specimens. 
Station 36 : One specimen. 
Station 51: Six specimens. 
Station 57: Fifteen specimens. 
Station 64: One specimen. 
Station 70 : Six specimens. 
Station 82 : One small specimen. 



BARBADOS-ANTIGUA REPORTS 53 

Family Ophiacanthidae 

Ophiacantha mesembria H. L. Clark 
Station 9 : Two small specimens. 
Station 15: One specimen. 
Station 28: Four small specimens. 
Station 37 : Two small specimens. 
Station 59 : One specimen. 

Order GNATHOPHIURIDA 
Family Amphiuridae 

Amphiura diducta Koehler 
Station 1 : One specimen. 

Amphiura palmeri Lyman 
Station 96 : Two specimens. 

Amphipholis limbata (Grube) 
Station 79 : One specimen. 

Amphiodia planispina (von Martens) 
Station 1 : One specimen, with the disc lacking. 

Ophiactis mulleri Liitken 
Station 11: One specimen. 

Station 67: Two specimens; one of these has three mouth 
papillae. 

Station 101: Twenty-two specimens. 
No locality : Two specimens. 

Ophiactis savignyi Miiller and Troschel 
Station 1 : One specimen. 

Ophiactis duplicata (Lyman) 
Station 6 : Three specimens. 
Station 45 : One specimen. 

Family Ophiotrichidae 

Ophiothrix angulaia Ayres 
Station 1 : Six specimens. 
Station 11 : Eight specimens. 
Station 13: One specimen. 



54 IOWA STUDIES IN NATURAL HISTOPY 

Station 18 : One specimen. 
Station 51 : One specimen. 
Station 65 : One specimen. 
Station 67 : Three specimens. 
Station 70: One specimen. 
Station 78 : Two specimens. 
Station 85 : Two specimens. 
Station 96 : Three specimens. 
Station 100: Five specimens. 

Barbados; Engineers' Pier, 15-20 feet. — Fragments. 
Barbados ; off Pelican Island, 4 fathoms ; from gorgonians and 
corals. — Seven specimens. 

Barbados ; off Pelican Island, 50 feet. — One small specimen. 
Barbados; off Needham's Point; diver. — Eight specimens. 
Station 101 : Four specimens. 
Antigua ; English Harbour ; in eel grass. — Two specimens. 

Ophiothrix lineata Lyman 
Barbados ; off Pelican Island, 4 fathoms ; from gorgonians and 
corals. — One specimen. 

Ophiothrix oerstedii Liitken 
Barbados; Engineers' Pier, 15-20 feet; from gorgonians; May 
18, 1918. — Two specimens. 
Barbados; Needham's Point; diver. — Ten specimens. 
Antigua ; English Harbour ; in eel grass. — Three specimens. 
Antigua; English Harbour; rocks. — One specimen. 

Ophiothrix suensonii Liitken 

Station 53: One specimen. 

Station 59: One specimen. 

Station 62: One specimen with the disc 14 mm. in diameter; 
the spines on the disc are much more numerous and shorter than 
usual. In life the disc was olive gray with five radial red bands, 
and the arms were whitish with the dorsal arm plates dark coral 
red and the ventral plates lighter. 

Station 89: One specimen. 

Barbados; Engineers' Pier, 15-20 feet; from gorgonians; May 
18, 1918. — Fifty-four specimens. 

Barbados ; off Pelican Island. — Two specimens. 



BARBADOS-ANTIGUA REPORTS 55 

Barbados ; off Pelican Island, 4 fathoms ; from gorgonians and 
corals. — Thirteen specimens. 

Barbados; Carlisle Bay, 20 feet; on gorgonians.— Twenty-nine 
specimens. 

Barbados; off Needham's Point; diver.— Twenty specimens. 

Barbados; off Hastings; June 5, 1918.— Thirteen specimens. 

Station 101 : Two specimens. 

Antigua ; English Harbour. — Seven specimens. 

Ophiothrix pallida Ljungman 
Station 96 : Two specimens. 

Order GHILOPHIURIDA 
Family Ophiochitonidae 

Ophionereis reticulata (Say) 

Station 1 : Three specimens. 

Station 67: One specimen. 

Station 70: One specimen. 

Station 79: One small specimen. 

Station 101 : One specimen. 

Antigua; English Harbour. — Seven specimens. 

Family Ophiocomidae 

Ophiocoma echinata L. Agassiz 

Station 96: One specimen. 

Barbados ; Pelican Island ; tide pools. — One specimen. 

Barbados ; Bathsheba ; tide pools. — Eleven specimens. 

Station 101 : One specimen. 

Antigua; English Harbour; rocks. — Three specimens. 

Antigua ; English Harbour ; in eel grass. — One specimen. 

Antigua; English Harbour. — Fifteen specimens. 

Antigua. — One specimen. 

Ophiocoma pumila Liitken 

Station 96 : One specimen. 

Barbados; Pelican Island; tide pools; May 11, 1918. — Four 
specimens. 

Barbados; Pelican Island. — One specimen. 

Barbados; Needham's Point; June 8, 1918. — Four specimens. 



56 IOWA STUDIES IN NATURAL HISTORY 

Antigua; English Harbour; rocks. — Fifteen specimens. 
Antigua; English Harbour. — Ten specimens. 

Ophiocoma riisei Liitken 

Station 1 : Five specimens. 

Station 96: Two specimens; one of these, small and without 
granules on the disc, was kindly identified for me by Dr. H. L. 
Clark. 

Station 100 : Three specimens. 

Station 101 : Five specimens. 

Antigua ; English Harbour ; rocks. — Seven small specimens. 

Antigua; English Harbour. — Seven specimens. 

Antigua ; Falmouth Harbour. — One specimen which in life was 
"deep reddish brown.' y 

No label. — One specimen. 

Ophiopsila hartmeyeri Koehler 

Station 53: One specimen. 

Station 96: One specimen. 

Family Ophiodermatidae 

Ophioderma appressa (Say) 

Station 11 : One small specimen. 

Barbados; Pelican Island; tide pools; May 11, 1918. — Two 
specimens. 

Barbados ; Pelican Island. — Ten specimens. 

Barbados; off Needham's Point; June 6, 1918. — Four speci- 
mens. 

Station 101 : Three specimens. 

Station 103: Five specimens. 

Station 104 : Two specimens. 

Antigua; English Harbour; in eel grass. — Sixteen specimens. 

Antigua; English Harbour. — Sixteen specimens. 

Antigua ; Falmouth Harbour ; in eel grass ; collected by W. K. 
Fisher. — Eighteen specimens. 

Ophioderma brevicauda (Say) 

Barbados ; Pelican Island ; tide pools. — Six specimens. 

Barbados; Pelican Island. — Seventeen specimens. 

Barbados; off Needham's Point; June 8, 1918. — One specimen. 

Antigua ; English Harbour. — Nine specimens. 



BARBADOS-ANTIGUA REPORTS 57 

Ophioderma cinerea (Lyman) 
Station 78 : One specimen. 
Antigua; English Harbour. — Five specimens. 

Ophioderma rubicunda Lyman 
Station 98 : One specimen. 
Pelican Island : One specimen. 
Station 101 : Three specimens. 

Family Ophiolepididae 

Ophiura acervata Lyman 
Station 116 : One specimen. 

Ophiomusiwm testudo Lyman 
Station 2 : One small specimen. 
Station 11: One small specimen. 
Station 26 : Two small specimens. 

Station 51 : Three small specimens, kindly determined for 
me toy Dr. H. L. Clark. 

Station 79 : One small specimen. 

Ophiomusium validum Ljungman 
Station 116 : One specimen. 

Ophionmsium sculptum Verrill 
Station 4 : Three specimens. 

Station 7: One specimen; "arms banded with orange on 
whitish/ ' 

Station 15: One specimen. 
Station 28: One specimen. 
Station 44: One specimen. 
Station 49 : One specimen. 

Ophiozona impressa (Liitken) 
Station 51 : One small specimen. 

Ophiozonello; nivea (Lyman) 
Station 1: One specimen. 
Station 3: One specimen. 
Station 26 : One specimen. 

Ophiozonella tessellata (Lyman) 
Station 62: One specimen. 



58 IOWA STUDIES IN NATURAL HISTORY 

Ophiolepis elegans Liitken 
Station 11: One specimen. 
Station 18: One specimen. 
^Barbados. — Three specimens. 
Antigua; English Harbour. — Eleven specimens. 

Ophiolepis paucispina Miiller and Trosehel 
Station 1 : One specimen. 
Antigua; English Harbour; in eel grass. — Thirteen specimens. 

LIST OF THE STATIONS, WITH THE SPECIES 
REPRESENTED AT EACH 

The Crinoids collected at these Stations are also given. 

Station 1: 

Amphiura diducta Ophionereis reticulata 

Amphiodia planispina Ophiocoma riisei 

Ophiactis savignyi Ophiozonella nivea 

Ophiothrix angulata Ophiolepis paucispina 

Station 2: 

Hemieuryale pustulata Ophiomusium testudo 



Station 3 : 
Station 4 : 



Leptonemaster venustus 
Ophiomusium sculptum 



Station 7: 

Astroschema oligactes Ophiomusium sculptum 

Asteroporpa annulata Leptonemaster venustus 

Democrinus rawsonii 
Station 9: 

Ophiacantha mesembria Comactinia meridionalis 

Station 11: 

Ophiactis mulleri Ophiolepis elegans 

Ophiothrix angulata Leptonemaster vemistus 

Ophioderma appressa Comactinia meridionalis 

Ophiomusium testudo Analcidometra armata 

Station 13 : 

Ophiothrix angulata Leptonemaster venustus 



BARBADOS-ANTIGUA REPORTS 59 

Station 14: 

Comactinia meridionalis 
Station 15 : 
Ophiacantha mesembria Ophiomusium sculptum 

Coccometra hagenii 
Station 18 : 
Ophiothrix angulata Ophiolepis elegans 

Leptonemaster venustus 
Station 26 : 
Ophiosciasma granulatum Ophiomusium testudo 

Station 28 : 

Ophiacantha mesembria Ophiomusium sculptum 

Station 34: 

Astroschema oligactes 
Station 35 : 

Astroschema oligactes 
Station 36 : 

Astroschema Iceve Hemieuryale pustulata 

Station 37 : 

Ophiacantha mesembria 
Station 41 : 

Asteroporpa annulata 
Station 44 : 

Ophiomusium sculptum 
Station 46 : 

Astroschema arenosum Leptonemaster venustus 

Station 49 : 

Ophiomusium sculptum 
Station 50 : 

Nemaster discoidea 
Station 51: 

Hemieuryale pustulata Ophiozona impressa 

Ophiothrix angulata Nemaster discoidea 

Ophiomusium testudo Comactinia meridionalis 

Station 53: 

Ophiothrix suensonii Nemaster iowensis 

Station 55: 

Astrocnida isidis 



€0 IOWA STUDIES IN NATURAL HISTORY 

Station 56 : 

Leptonemaster venustus 
Station 57 : 

Hemieuryale pustulata 
Station 58 : 

Asteroporpa annulata 
Station 59 : 

Astroschema tenue Ophiothrix suensonii 

Ophiacantha mesembria Leptonemaster venustus 

Station 62 : 

Ophiothrix suensonii Ophiozonella tessellata 

Station 64 : 

Hemieuryale pustulata 
Station 65: 

Ophiothrix angulata 
Station 67 : 

Ophiactis mulleri Leptonemaster venustus 

Ophiothrix angulata Comactinia meridionalis 

Station 70 : 

Hemieuryale pustulata Ophiothrix angulata 

Ophionereis reticulata 
Station 78 : 

Ophiothrix angulata Leptonemaster venustus 

Ophioderma cinerea Comactinia meridionalis 

Station 79 : 

Amphipholis limbata Ophiomusium testudo 

Ophionereis reticulata Nemaster discoidea 

Station 82 : 

Hemieuryale pustulata 
Station 85: 
Ophiothrix angulata Comactinia meridionalis 

Station 89 : 

Ophiothrix suensonii 
Station 92: 

Nemaster discoidea 



BARBADOS-ANTIGUA REPORTS 61 

Station 96 : 

Ophiothrix angulata Ophiocoma pumila 

Ophiocoma echinata Ophiocoma riisei 

Comactinia meridionalis 
Station 97 : 
Astrocyclus ccecilia Sigsbeia murrhina 

Nemaster iowensis 
Station 98 : 

Station 99 : 



Nemaster iowensis 
Nemaster iowensis 



Station 100 : 

Ophiothrix angulata Ophiocoma riisei 

Barbados; Engineers' Pier, 15-20 feet 
Ophiothrix angulata Ophiothrix oerstedii 

Ophiothrix suensonii 

Barbados; Engineers' Pier, 25 feet 

Nemaster iowensis 
Barbados; Pelican Island, tide pools 
Ophiomyxa flaccida Ophiocoma pumila 

Ophiocoma echinata Ophioderma appressa 

Ophioderma brevicauda 

Barbados ; off Pelican Island, 4 fathoms 
Ophiothrix angulata Ophiothrix lineata 

Ophiothrix suensonii 

Barbados; off Pelican Island, 50 feet 

Ophiothrix angulata 
Barbados ; off Pelican Island 

Ophiothrix suensonii Ophioderma appressa 

Ophiocoma pumila Ophioderma brevicauda 

Barbados; Carlisle Bay, 5 fathoms 

Astrophytum muricatum 
Barbados ; Carlisle Bay, 20 feet 
Astrophytum muricatum Ophiothrix suensonii 



62 IOWA STUDIES IN NATURAL HISTORY 

Barbados; off Needham's Point 
Ophiothrix angulata Ophiocoma pumila 

Ophiothrix oerstedii Ophioderma appressa 

Ophiothrix suensonii Ophioderma brevicauda 

Barbados ; off Hastings 

Ophiothrix suensonii 

Barbados; Bathsheba 

Ophiocoma echinata 

Barbados; from fish pots 

Astrophytum muricatum 
Barbados 

Sigsbeia murrhina Nemaster discoidea 

Nemaster iowensis Comactinia meridionalis 

^Barbados 

Ophiolepis elegans 
Station 101 : 

Ophiactis mulleri Ophiocoma echinata 

Ophiothrix angulata Ophiocoma riisei 

Ophiothrix suensonii Ophioderma appressa 

Ophionereis reticulata Ophioderma rubicunda 

Nemaster iowensis 



Station 103 : 
Station 104 : 



Ophioderma appressa 
Ophioderma appressa 



Station 116: 

Ophiura acervata Ophiomusium validum 

Antigua; English Harbour, in eel grass 
Ophiothrix angulata Ophiocoma echinata 

Ophiothrix oerstedii Ophioderma appressa 

Ophiolepis paucispina 

Antigua; English Harbour, rocks 
Ophiothrix oerstedii Ophiocoma pumila 

Ophiocoma echinata Ophiocoma riisei 



BARBADOS-ANTIGUA REPORTS 



63 



Antigua; English Harbour 
Ophiomyxa flaccida 
Ophiothrix suensonii 
Ophionereis reticulata 
Ophiocoma echinata 
Ophiocoma pumila 

Antigua ; Falmouth Harbour 
Ophiocoma pumila 

Antigua 



Ophiocoma riisei 
Ophioderma appressa 
Ophioderma brevicauda 
Ophioderma cinerea 
Ophiolepis elegans 



Ophioderma appressa 



Ophiocoma echinata 



REPORT ON THE BRACHYURA 

Collected by the Barbados- Antigua Expedition 
from the University of Iowa in 1918 

Mary J. Rathbun 

Associate in Zoology, U. S. National Museum 



INTRODUCTION 

Hughes in his "Natural History of Barbados'', 1750, 1 enu- 
merates fifteen kinds of crabs, but the descriptions are so brief 
and the names so trivial that it is impossible to determine most 
of the species with any great degree of certainty. Only two of 
the brachyuran crabs are figured; one, the Horned Crab (pi. 
XXV, fig. 3) is an undoubted Stenocionops furcata, the other, 
the Lazy Crab, (pi. XXV, fig. 1) is a composite, having the 
chelipeds and ambulatory legs of Mithmx spinosissimus attached 
to the body of a Parthenopid crab, Daldorfia horrida (= Parthe- 
nope horrida of authors), an Indo-Pacific species. 

From the dredgings of the U. S. Coast Survey steamers 
"Blake" and "Hassler", A. Milne Edwards 1 in 1880 published 
a list which includes thirty-eight species of brachyuran crabs 
from the waters about Barbados. This is supplemented by the 
later report (1902) on the Oxystomes of the same collection by 
Milne Edwards and Bouvier, 1 which adds three species to the 
earlier list. 

The present expedition obtained ninety-three species of 
brachyurans of which only one species is found to be undescribed. 
The range of twenty-nine species is extended by their capture at 
Barbados. 

LIST OF SPECIES 

Tribe Brachyura 

Subtribe Oxystomata 

Family Dromiidae 

Dromia erythropus (George Edwards) 

Rathbun, Ann. Inst. Jamaica, vol. I, 1897, p. 39. 



i See bibliography on page 89. 

5 65 



66 IOWA STUDIES IN NATURAL HISTORY 

Carlisle Bay, Barbados ; in fish pot ; 1 $ . 
Brought up by diver off Pelican Island, Barbados ; 1 $ ovige- 
rous. 

Dromidia antillensis Stimpson 
Rathbun, Ann. Inst. Jamaica, vol. I, 1897, p. 39. 
Barbados ; 1 9 ovigerous. 

Family Dorippidae 
Cyclodobippe perpusilla (Rathbun) 
Clythrocerus perpusillus Rathbun, Bull. U. S. F. C, vol. XX 
for 1900, part 2, 1901, p. 90, text-fig. 4. 
One mile S. W. of Pelican Island, Barbados; 38 fathoms; 
bottom of fine coral fragments ; May 13 ; sta. 1 ; 1 $ , the same 
size as the type. 

Known only from the type specimen, off Vieques. 

Family Raninidae 

Raninoides lcevis (Latreille) 

Ranina loevis Latreille, Encyc. Meth., Entom., vol. X, 1825, p. 

268. 
Raninoides levis Milne Edwards, Hist. Nat. Crust., vol. II, 1837, 
p. 197. 

Barbados; W. by N. of Pelican Island 2% miles and drifting 
off shore ; 107 fathoms ; bottom of fine sand ; tangles ; May 16 ; 
sta. 10 ; 1 small 6 , 1 young. 

In the young specimen, carapace 6 mm. long, the supra-orbital 
margin between the two fissures is not produced in a spine but is 
obliquely truncate. 

Family Calappidae 
Calappa angusta A. Milne Edwards 
Bull. M. C. Z., vol. VIII, 1880, p. 18. 

Barbados; Lazaretto E. by N. y 2 N., Pelican Island S. E.; 
bottom of fine sand ; June 7 ; sta. 88 ; 1 juv. 

Taken at Barbados by the "Hassler," 100 fathoms, and by 
the " Blake/ ' 103 fathoms. 

Calappa gallus (Herbst) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 85. 

Pelican Island, Barbados ; in fish pot ; 1 $ . 



BARBADOS-ANTIGUA REPORTS 67 

Cycloes baibdii Stimpson 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 85. 

English Harbour, Antigua ; 1 $ , 10.4 mm. long. 

One mile S. W. of Pelican Island, Barbados ; 38 fathoms ; bot- 
tom of fine coral fragments ; May 13; sta. 1 ; 1 juv. 

In the West Indies, this species seems not to have been reported 
south of Guadeloupe ; although it occurs in the Pacific at Panama. 

Family Leucosiidae 

Ebalia stimpsonii A. Milne Edwards 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 

p. 87. 
Barbados ; Cable Station E. S. by E., Paynes Bay Church N. 

E., off shore % m ^ e ; 35-75 fathoms ; bottom alternate sand and 

rocks; sta. 78; 1 6. 
Described from off Barbados, 7 to 50 fathoms, " Blake.' ' 

Iliacantha subglobosa Stimpson 
Bull. M. C. Z., vol. II, 1871, p. 155. 

W. by N. of Pelican Island, Barbados, 2 miles ; 75-80 fathoms ; 
sand bottom ; sta. 3 ; 1 $ juv. 

S. of St. Mathias Church, Barbados, 1 mile ; 60 fathoms ; bot- 
tom of coarse sand ; May 20 ; sta. 21 ; 1 6 . 

W. by N. of Telegraph Station, Barbados, y 2 mile or more off 
shore, about edge of drop off; 50-70 fathoms; bottom rocky; 
tangles; June 1; sta. 66 and 67; 2 9 juv. 

Dredged by the " Blake" at Barbados, 56 to 94 fathoms. 
Subtribe Brachygnatha 
Superfamily Brachyrhyncha 
Family Portunidse 

Portunus (Portunus) sulcatus (A. Milne Edwards) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 45. 

English Harbour, Antigua; by electric light; July; 1 juv., 3.2 
mm. long. 

Bathsheba, Barbados; 1 6 juv. 

Pelican Island, Barbados ; tide pool ; May 13 ; 1 6 juv. 



68 IOWA STUDIES IN NATURAL HISTORY 

Portunus (Achelous) ordwayi (Stimpson) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 46. 

English Harbour, Antigua ; electric light ; July, 1918 ; 1 juv. 

Callinectes ornatus Ordway 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 48. 

Barbados ; 1 adult $ . 

Cronius ruber (Lamarck) 
Charybdella rubra Rathbun, Bull. U. S. F. C, vol. XX for 1900, 
part 2, 1901, p. 51. 
Antigua; 1 juv. 

Family Xanthidae 

Liomera longimana A. Milne Edwards 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 25. 

Barbados ; May 15 ; 10 6 9 $ ovig. On old coral ; May 31 ; 
8 6 15 $ . On old coral heads; June 4; 12 6 11 $ (1 ovig.). 

Needham Point, Barbados ; May 18 ; 3 6 1 $ . 

One mile S. of sta. 19, off Needham Point ; 84 fathoms ; rocky 
bottom ; sta. 20 ; 2 6 4 $ . 

Okra Reef, Barbados; May 13; 35 6 44 $ (35 ovig.) 8 juv. 

Not previously noted south of Guadeloupe. 
Liomera dispar (Stimpson) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 25. 

Pillars of Hercules, Antigua ; 1 $ . 

Barbados; May 15; 6 6 21 $ (8 ovig.). On old coral, May 
31; 3 6 13 $ 2 juv. On old coral heads; June 4; 4 6 4$. 

One mile S. of sta. 19, off Needham Point, Barbados; 84 
fathoms ; rocky bottom ; sta. 20 ; 2 6 4$ (2 ovig.). 

Okra Reef, Barbados; May 13; 3 $ 14 $ (7 ovig.). 

Not previously recorded south of Porto Rico. 
Platypodia spectabilis (Herbst) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 26. 

Needham 's Point, Barbados; May 18; 1 6 1 9 ovig. 



BARBADOS-ANTIGUA REPORTS 69 

Leptodius florid anus (Gibbes) 

Rathbun, Bull. U. S. F. C., vol. XX for 1900, part 2, 1901, 
p. 27. 

Pillars of Hercules, Antigua ; 1 9 . ' 

Barbados ; 8 6 3 9 ovig. 

Pelican Island, Barbados ; tide pools ; 2 6 . May 11 ; 3 6 . 
May 13; 4 9 (3 ovig.). Shallow;! 6 1 9 juv. 

Okra Reef, Barbados ; May 13 ; 1 juv. 

Xanthodius parvulus (Fabricius) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 27. 

Pelican Island, Barbados ; shallow ; 2 6 . In tide pool ; May 
11; 1 $ juv. 1 9. 

Barbados ; 1 6 . 

No label; 1 6. 

Cycloxanthops denticulatus (White) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 27. 

Pillars of Hercules, Antigua ; 1 6 juv. 
Pelican Island, Barbados; tide pool; 1 6 . 
Bathsheba, Barbados; 2 juv. 

Panopeus herbstii Milne Edwards 
Eupanopeus herbstii Rathbun, Bull. U. S. F. C, vol. XX for 
1900, part 2, 1901, p. 28. 
English Harbour, Antigua ; 1 6 juv. 
Pillars of Hercules, Antigua ; 1 6 thin shell, 2 juv. 
Barbados ; 2 6 1 9 . 

Panopeus occidentals Saussure 

Eupanopeus occidentalis Rathbun, Bull. U. S. F. C, vol. XX for 
1900, part 2, 1901, p. 29. 
Pillars of Hercules, Antigua; 1 9 . 

Panopeus americanus Saussure 

Eupanopeus americanus Rathbun, Bull. U. S. F. C, voL XX for 
1900, part 2, 1901, p. 29. 
Pillars of Hercules, Antigua ; 1 6 small. 



70 IOWA STUDIES IN NATURAL HISTORY 

Panopeus harttii Smith 
Eupanopeus harttii Rathbun, Bull. U. S. F. C., vol. XX for 1900, 
part 2, 1901, p. 29. 
Pillars of Hercules, Antigua ; 1 9 . 
Pelican Island, Barbados ; shallow ; 1 6 . 

ElJRYPANOPEUS ABBREVIATUS (Stimpson) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 30. 

Pillars of Hercules, Antigua ; 1 6 1 $ 1 juv. 

Hexapanopeus hemphillii (Benedict and Rathbun) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 31. 

Barbados ; from old coral head ; June 4 ; 1 6 of medium size, 
identified with some doubt, as both sides of the body are infested 
with an isopod parasite which has so distorted the carapace that 
the lateral teeth are abnormal and unlike on the two sides. 

Not before found south of St. Thomas and Porto Rico. 
Micropanope lobiprons A. Milne Edwards 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 32. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 
of fine coral fragments ; May 13 ; sta. 1 ; 2 6 2 9 . 

One-half mile W. of sta. 17 ; 40 fathoms ; bottom coarse sand ; 
May 18 ; sta. 18 ; 1 $ . 

W. N. W. of Lazaretto, Barbados ; N. N. W. of Pelican Island ; 
33 fathoms; bottom rocky; dredge; May 27; sta. 51; 9 $ (1 
ovig., 3 with Rhizocephalids). 

Cable station, Barbados, bears E. by S., Lazaretto, E. S. E. y 2 
S. ; 35-60 fathoms ; bottom mostly rocky, on steep slope ; tangles ; 
June 3 ; sta. 75 ; 1 6 . 

Cable station E. S. by E., Paynes Bay Church N. E., off shore 
% mile ; 35-75 fathoms ; bottom alternate sand and rocks ; June 
3 ; sta. 78 ; 1 $ with a small Rhizocephalid under the abdomen. 

W. by N. of Telegraph Station, Barbados; little more than a 
half mile off ; 30-65 fathoms ; bottom of rocks and sand ; June 5 ; 
sta. 79; 3 $ (2 with a Rhizocephalid larger than the abdomen 
but attached under it). 

Taken at Barbados by the " Blake' ' in 94 fathoms. 



BARBADOS-ANTIGUA REPORTS 71 

ACTAEA RUPOPUNCTATA NODOSA StimpSOIl 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 33. 

\y± miles due W. from white lighthouse at Needham Point, 
Barbados ; in line with red house ; 67-70 fathoms ; bottom stony ; 
May 17 ; sta. 11 ; 1 6 juv. 

Taken at Barbados by the " Blake' ' in 94 fathoms. 

Actaea setigera (Milne Edwards) 

Rathbun, Bull. U. S. P. C, vol. XX for 1900, part 2, 1901, 
p. 34. 

Pillars of Hercules, English Harbour, Antigua ; 2 6 . 

English Harbour, Antigua ; 1 6 1 juv. 

Okra Reef, Barbados ; May 13 ; 1 $ 3 juv. 

Peliean Island, Barbados; 1 9 juv. 

Needham Point, Barbados ; 1 6 juv. May 18 ; 1 $ juv. 

Barbados ; 1 6 . May 15 ; 1 6 4 juv. Prom old coral head ; 
May 31 ; 1 $ juv., 1 juv. Prom coral heads ; June 4 ; 1 6 1 $ 
juv. 

Not before recorded from so far south. 

Actaea bifrons Rathbun 

Bull. U. S. P. C, vol. XX for 1900, part 2, 1901, p. 34. 

Barbados ; 1 6 . 

Shoal Bank, Barbados ; 30 fathoms ; bottom rough ; June 12 ; 
sta. 96; 1 6. 

Shoal Bank, about 3 miles W. of Needham Point; 20-40 fath- 
oms ; sponge bottom ; sta. 101 ; 1 6 . 

This species has been found only off Porto Rico and Colon. 

Xanthias nutting Rathbun 
Bull. U. S. P. C, vol. XX for 1900, part 2, 1901, p. 35. 
Barbados ; 1 small 6 . 

Xanthiam granulimanus (Stimpson) 
Plate II, figs. 2 and 3. 
Rathbun, Bull. Lab. Nat. Hist. State Univ. Iowa, vol. IV, 
1898, p. 271. 

Barbados ; from coral heads ; June 4 ; 1 $ ovigerous. 
Known previously from Bahamas and Cuba. 



72 IOWA STUDIES IN NATURAL HISTORY 

Carapace suboval, front slightly advanced, regions indicated by shallow 
furrows; anterior and antero-lateral regions irregularly granulated, the 
coarser granules forming short lines near the lateral teeth. Edge of front 
bow-shaped, a short median slit. Upper margin of orbit transverse and a 
little sinuous. Four antero-lateral teeth beside the angle of the orbit, first 
tooth low, remote from orbit, remaining teeth sharp-pointed, edge of orbit 
and teeth granulate. Lower surface of carapace densely granulate, lower 
margin of orbit more advanced than upper, with a V-shaped outer sinus and 
a thick, triangular tooth at inner angle. 

Chelipeds unequal, exposed surfaces of carpus, manus and proximal ends 
of fingers coarsely granulate; fingers deeply grooved, the granules extend- 
ing more than half the length of the intervening ridges in the smaller chela. 
Legs hairy, especially the last three segments, upper margin of merus and 
upper surfaces of carpus and propodus denticulate. 

The above description was made from a Bahama specimen 
( $ ) in the U. S. National Museum. The Barbados specimen is 
much smaller but ovigerous. Length of carapace 3.7 mm., width 
5.2 mm. 

Chlorodiella longimana (Milne Edwards) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 36. 

Barbados; May 15; 3 6 7 $ (1 ovig.) 2 juv. 

Coral heads ; May 31 ; 1 6 . On old coral heads ; June 4 ; 3 $ 
2 9. 

Okra Reef, Barbados; May 13; 2 6 2 $ . 

One mile S. of sta. 19, off Needham Point, Barbados ; 84 fath- 
oms ; bottom rocky ; sta. 20 ; 1 6 . 

Not previously recorded from Barbados; known from Guade- 
loupe and Curagao. 

Ozius reticulatus (Desbonne and Schramm) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 

p. 37. 

Barbados ; 1 $ . 

Not previously recorded from Barbados ; the nearest points are 

Guadeloupe and Puerto Colombia. 

Pilumnus caribaeus Desbonne 
In Desbonne and Schramm, Crust. Guadeloupe, 1867, p. 32. 
Needham Point, Barbados ; May 18 ; 1 $ . 

In this species the lateral spines are 4, including the spine at the outer 



BARBADOS-ANTIGUA REPORTS 73 

angle of the orbit; the first and often the second spine is bifid. In the 
Barbados specimen, there is a spine immediately following the orbital spine, 
which is subequal to it, and the second spine also is double, composed of 2 
separate spines, the hinder of the two being smaller; in short, the margin 
appears to be 6-spined. Two spines on the dorsal surface of the hepatic 
region and one on the branchial region near by, are larger than usual. The 
outer surface of the larger as well as of the smaller palm is rough all over. 

Not previously known south of Guadeloupe. 

PlLUMNUS BARBADENSIS, Sp. nOV. 

Plate I 

Type-locality. — Barbados ; from old coral heads ; May 31 ; 3 5 
2 $ ; the largest 6 has been selected as the holotype. (Cat. No. 
, Mus. Univ. Iowa.) 

Additional lots. — Okra Reef, Barbados; May 13; 2 young. 
Barbados ; from coral heads ; June 4 ; 5 small. 

Measurements. — Male holotype, length of carapace 6.7, width 
9.4 mm. The largest $ is 12.3 mm. wide and too broken to per- 
mit measurement of the length ; figured $ , length 7.6, width 
10.7 mm. 

Description. — Carapace suboval, antero-lateral margin arched but shorter 
than the posterolateral margin. Surface covered with a short, soft, sparse 
pubescence which does not conceal the carapace. Furrows between regions 
and gastric subregions well marked. Surface minutely roughened, especially 
along the front and antero-lateral regions where the granules are acutely 
pointed. The lobes of the front are oblique, slightly convex save at outer 
end which is right angled ; edge crenulate. Inner orbital angle acute, 
elevated; upper orbital margin sloping obliquely outward and backward to 
a slight outer tooth. Edge of orbit finely denticulate. Antero-lateral 
margin armed with 3 slender, acuminate spines, each set in a stout, trian- 
gular, denticulate base. The carapace is widest at the posterior pair of 
these spines; the two interspaces are subequal; between the anterior spine 
and the orbital angle there is a spinule, little larger than the sharp denticles 
of the neighboring surface, and confused in dorsal view with several sub- 
hepatic spinules. Suborbital region covered with coarse, acute granules. 
Lower orbital region more advanced than upper, its spinules more elongate; 
spinule at inner angle a little larger and more pronounced. 

Chelipeds very unequal, thinly clothed with longer hairs than the cara- 
pace; carpus covered with acute granules, and with two spinules, one above 
the other at the inner angle. Only the proximal third or less of the major 
palm is rough with granules, the roughness forming an oblique band border- 
ing the carpus but stopping short of the lower margin; the proximal two- 



74 IOWA STUDIES IN NATURAL HISTORY 

thirds of the lower edge is separately roughened; remainder of palm smooth 
and naked ; fingers of J dark brown with light tips, color not reaching quite 
to base of immovable finger, color line vertical; a narrow interdigital gape. 
In the minor eheliped the entire outer surface of the palm is very rough, the 
granules arranged for the most part longitudinally; the fingers are less 
gaping and are deeply grooved, the ridges very rough. 

In the female, the fingers are a lighter brown and in the largest female 
the roughness on the major palm is less extensive. 

Ambulatory legs slender, bordered with long hair; merus slightly en- 
larged, upper margin edged with slender spines. Dactyli noticeably slender. 

Relationships. — Of the Pilumnus in the West Indian fauna, 
this approaches nearest to P. spinipes (= Micropanope spinipes 
A. Milne Edwards 1 ) in many details such as the ornamentation 
of the antero-lateral margin, the partial roughness of the major 
palm, the slender legs. On the other hand, the carapace of 
barbadensis is more oval and more convex, front more deflexed, 
and the minor palm rough all over, while in spinipes the granu- 
lation is similar on the two palms. 

P. andrewsii Rathbun 2 is a broad species with antero-lateral 
margin similar to that of barbadensis, but the interregional fur- 
rows are deeper, the upper orbital border has two small but dis- 
tinct emarginations, the major palm is smooth, the minor one 
nearly so. 

Pilumnus floridanus Stimpson 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 40. 

W. N. W. of Lazaretto, N. N. W. of Pelican Island, Barbados; 
dredged in from 80-100 fathoms to where rocks begin at about 35 
fathoms ; bag full of coarse sand ; sta. 53 ; 1 9 ovig. 

Not previously known south of Porto Rico and St. Thomas. 

Hetbractaea ceratopus (Stimpson) 

Pilumnus ceratopus Stimpson, Ann. Lye. Nat. Hist. N. Y., vol. 

VII, 1860, p. 215. 

Needham Point, Barbados; by diver; 1 9 . 

Barbados; May 22; 1 juv. From coral heads; June 4; 1 6 
4 $. 

Not recorded south of Guadeloupe. 



1 Crust. Reg. Mex., 1880, p. 326, pi. LIV, fig. 3. 

2 Bull. Lab. Nat. Hist. State Univ. Iowa, vol. IV, 1898, p. 266, pi. V, fig. 2. 



BARBADOS-ANTIGUA REPORTS 75 

Eriphia gonagra (Fabricius) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 42. 

Pillars of Hercules, English Harbour, Antigua ; 1 juv. 

Barbados; 1 6 3 $ (all small). 

Bathsheba, Barbados; 3 6 (the largest one with abnormal 
abdomen, which is intermediate in width between 6 and adult 

«). 
Needham Point, Barbados; 3 $ (1 ovig.). 
Pelican Island, Barbados ; tide pool ; May 11 ; 1 $ , 1 juv. 
No label; 3 $ 4 9 (3 ovig.). 

Melybia thalamita Stimpson 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 43. 

Barbados ;2 $ 1 $ ovig. From broken coral ; May 27 ; 1 $ 
ovig. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 
of fine coral fragments ; May 13 ; sta. 1 ; 1 $ ovig., 2 juv. 

Not previously recorded from Barbados ; found at Porto Rico 
and Colon. 

Domecia hispida Eydoux and Souleyet 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 43. 

Barbados ; May 15 ; 1 $ ovig. May 22 ; 1 juv. In coral heads ; 
May 31 ; 1 $ . From coral heads ; June 4 ; 1 6 . Living in Aero- 
pom; 1 $ 3 $ ovig. 1 young. 

Okra Reef, Barbados; May 13; 1 6 6 $ (4 ovig.). 

Needham Point, Barbados; May 18; 1 6 . 

One mile S. of sta. 19, off Needham Point ; 84 fathoms ; bottom 
rocky; sta. 20; 1 6 4 $ (2 ovig.). 

W. by N. of Pelican Island, iy 2 miles; 80 fathoms; bottom 
rocky ; tangles without weight ; May 16 ; sta. 7 ; 1 young. 

Family Goneplacidae 

Goneplax barbata (A. Milne Edwards) 

Rathbun, Bull. U. S. N. M., No. XCVII, 1918, p. 26, pi. IV, 
figs. 1 and 3; pi. V. 



76 IOWA STUDIES IN NATURAL HISTORY 

W. by N. of Pelican Island, Barbados, 2 miles ; 75-80 fathoms ; 
sand bottom ; May 15 ; sta. 3 ; 1 $ immature. 

This specimen unites the characters of G. barbata 1 and G. 
sigsbei, 2 as given in my monograph (pp. 26-27). It will be 
noted there that all the specimens (4) of barbata recorded are 
male, while both those of sigsbei are female. The specimen in 
hand has the lateral dentation of barbata, as shown in plate V, 
while lacking a branchial ridge, an orbital notch, and a patch of 
hair on the cheliped, which three characters link it to sigsbei. 
There is a very small but sharp spine on the upper margin of the 
arm and the inner angle of the wrist, not the prominent, curved 
spine of typical barbata, nor the blunt tooth of sigsbei. 

Both barbata and sigsbei are recorded from off Grenada, and 
barbata also from Gulf of Mexico and Straits of Florida. 

Panoplax depressa Stimpson 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 47, pL 
XII, figs. 1 and 2, text-fig. 21. 
Barbados ; 1 6 1 $ . From broken coral ; May 27 ; 1 6 . 
Not previously noted south of Porto Rico. 

Family Pinnotheridae 

Parapinnixa hendersoni Rathbun 
Bull. U. S. Nat. Mus., No. XCVII, p. 109, 1918, pi. XXVI, 

figs. 1-5. 

English Harbour, Antigua; by electric light; July; 1 5 2 $. 
This extends the range of the species, which heretofore has 

been found in N. W. Cuba and on the west coast of Florida. 

Family Cymopoliidae 

Cymopolia apfinis (A. Milne Edwards and Bouvier) 
Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 196, pi. 

XLVI, pi. XLVII, fig. 3, text-fig. 121. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 

of fine coral fragments ; May 13 ; sta. 1 ; 1 6 1 $ , both immature. 
Previously taken off Barbados in 68 fathoms by the U. S. C. S. 

Str. " Blake/ ' 



1 Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 26, pi. IV, figs. 1 and 3, 
pi. V. 

2 Op. cit., p. 26, pi. IV, figs. 2 and 4. 



BARBADOS-ANTIGUA REPORTS 77 

Cymopolia bahamensis (Rathbun) 

Rathbun, Bull. U. S. Nat. Mm, No. XCVII, 1918, p. 200, pi. 
XLVII, figs. 1 and 2. 

Barbados; Lazaretto bears S. E. by E., y 2 mile off shore; 35 
fathoms; bottom rocky; tangles; May 24; sta. 42; 1 $ ovig. 

Known only from the Bahamas. 

Cymopolia sica A. Milne Edwards 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 208, pi. 
XL, figs. 3 and 4, text-fig. 127. 

1% miles W. of Telegraph Station, Barbados; 118 fathoms; 
bottom of fine sand ; May 30 ; sta. 60 ; 1 $ ovig. 

Taken by the " Blake' ' off Barbados in 82 fathoms. 

Family Grapsidae 

Grapsus grapsus (Linnaeus) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 227, pis. 
LIII and LIV, text-fig. 135. 
Barbados; 3 6 4 $ (2 ovig.). 

Geograpsus lividus (Milne Edwards) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 232, 
pi. LV. 

Pelican Island, Barbados; May 18; 1 9 ; nocturnal; color in 
life, light olive brown, marbled on carapace with dark Van Dyke 
brown; legs faintly spotted. 

Goniopsis cruentata (Latreille) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 237, pi. 
LVII, text-fig. 136. 

Bridgetown, Barbados; mangrove swamp; 2 6 1 $ ; 1 6 is 
shedding. 

N. of Bridgetown, mangrove swamp ; 1 $ . 

Pachygrapsus transversus (Gibbes) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 244, pi. 
LVI, figs. 2 and 3. 

Pillars of Hercules, Antigua; 4 6 4 $ (3 ovig.). 
English Harbour, Antigua; 1 6 1 $ ovig. 



78 IOWA STUDIES IN NATURAL HISTORY 

Bathsheba, Barbados ; 1 6 . 
Needham Point, Barbados ; 1 $ . 
Barbados; 1 $ ovig. 

Euchirograpsus americanus A. Milne Edwards 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 282, pi. 
LXXIV, text-fig. 144. 

W. of Telegraph Station, Barbados, 1 mile; 86 fathoms; bot- 
tom rocky ; May 30 ; sta. 59 ; 1 6 . 

Cable station, Barbados, bears E. by S., Lazaretto E. S. E. 
y 2 S. ; 35-60 fathoms ; bottom mostly rocky, working on steep 
slope; tangles; June 3; sta. 75; 1 9 1 juv. 

The type-locality is off Barbados, 69 fathoms, " Blake/ ' 

Aratus pisonii (Milne Edwards) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 323, 
pi. XCVI. 

English Harbour, Antigua ; 1 $ . 

Pillars of Hercules, Antigua; 2 $ (1 ovig.). 

Plagusia depressa (Fabricius) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 332, pi. 
CI, text-fig. 154. 
Barbados; 1 old male. 
Bathsheba, Barbados ; 1 small but mature $ . 

Percnon gibbesi (Milne Edwards) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 337, 
pi. CV. 

Pillars of Hercules, Antigua ; 2 6 3 $ (1 juv.). 
English Harbour, Antigua ; 2 5 juv. 
Okra Reef, Barbados ; May 13 ; 1 6 juv. 

Family Gecarcinidae 

Cardisoma guanhumi Latreille 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 341, pis. 
CVI and CVII, text-fig. 155. 

Bridgetown, Barbados ; 1 large, well-developed 6 , 1 adult $ . 
Mangrove swamp, north of Bridgetown ; 1 young $ . 



BARBADOS-ANTIGUA REPORTS 79 

Ucides cordatus (Linnaeus) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 347, pis. 
CX-CXIII, pi. CLIX, figs. 3 and 4, text-fig. 158. 

Barbados; 1 6 small. 

Antigua ; mangrove swamp ; 2 large 6 . The larger has a 
carapace 73.7 mm. long, 100 mm. wide. The greatest width com- 
pared to the length is intermediate between that given in my 
monograph for a smaller specimen of cordatus and the width of 
occidentalis. 

This Antigua specimen lacks the first ambulatory leg on the 
right side; the first leg on the left side is shorter than the second 
leg, but may not be normal. 

The smaller specimen of the two has the ambulatory legs of the 
right side normal ; the first leg on the left side is no longer than, 
indeed, a trifle shorter than the second leg. 

Both these specimens have the palm straighter below than in 
the specimens previously described by me. In spite of these vari- 
ations in cordatus, there is no likelihood of confusion with occi- 
dentalis, as the palms of the latter are longer and slenderer than 
any of the cordatus examined, and the carapace is narrower be- 
hind in proportion to its greatest width. 

Gecabcinus lateralis (Freminville) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 355, pis. 
CXIX and CXX, text-fig. 161. 
Barbados; 1 6 1 9 1 juv. 

Family Ocypodidae 

OCYPODE ALBICANS BoSC 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 367, pis. 
CXXVII and CXXVIII. 
Barbados ; beach on south coast ; 2 6 . 
Pelican Island, Barbados ; 1 $ . 

Uca mobdax (Smith) 

Rathbun, Bull. U. S. Nat. Mus., No. XCVII, 1918, p. 391, pi. 
CXXXIV, figs. 3 and 4, text-fig. 166. 

English Harbour, Antigua ; 2 6 . In mangrove swamp ; 1 6 , 
large. 



80 IOWA STUDIES IN NATURAL HISTORY 

N. of Bridgetown, Barbados ; mangrove swamp ; 7 5 6 $ , of 
medium size. 

Superfamily Oxyrhyncha 

Family Parthenopidae 

Pabthenope (Platylambrus) fraterculus (Stimpson) 

Lambrus fraterculus Stimpson, Bull. M. C. Z., vol. II, 1871, p. 

130. 

Off Lazaretto, Barbados; 20 fathoms; bottom rough; tangles; 
June 6; sta. 87; 1 6 . 

This specimen has the dorsal projections more acute than cus- 
tomary, and the chelipeds a little longer, with sharper teeth or 
spines. 

Not before known from the West Indies. Its southern boun- 
dary has been Yucatan in the west, Miami in the east. 

SOLENOLAMBRUS TENELLUS Stimpson 

Bull. M. C. Z., vol. II, 1871, p. 134. 

Barbados; Lazaretto bears S. E. by E., y 2 mile off shore; 35 
fathoms ; bottom rocky ; tangles ; May 24 ; sta. 42 ; 1 $ ovig. 

Dredged off Barbados by the "Hassler," 100 fathoms, and by 
the " Blake' ' in 56 to 103 fathoms. 

Family Inachidae 
Subfamily Inachinae 
Stenorynchus Sagittarius (Fabrieius) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 53. 

N. W. i/ 2 N - ° f Pelican Island, Barbados, W. i/ 2 S. of Laza- 
retto ; 80 fathoms ; bottom fine sand ; May 27 ; sta. 49 ; 1 6 . 

Shoal Bank, Barbados, about 3 miles W. of Needham Point; 
20-40 fathoms ; sponge bottom ; sta. 101 ; 1 6 . 

Taken at Barbados by the " Blake' ' in 94 fathoms. 

PODOCHELA HYPOGLYPHA (Stimpson) 

Podonema hypoglypha Stimpson, Bull. M. C. Z., vol. II, 1871, 
p. 127. 
Barbados; Paynes Bay Church bears E. N. E. and the Laza- 



BARBADOS-ANTIGUA REPORTS 81 

retto S. E. by S., off shore y 2 mile ; 50 fathoms ; bottom rocky ; 
tangles ; May 31 ; sta. 64 ; 1 small but adult male. 
Not before noted south of Guadeloupe. 

PODOCHELA GRACILIPES StimpSOn 

Bull. M. C. Z., vol. II, 1871, p. 126. 

Lazaretto, Barbados, bears S. E. by E., y 2 mile off shore; 35 
fathoms ; bottom rocky ; tangles ; May 24 ; sta. 42 ; 1 6 . 

Cable station, Barbados, bears E. by S., Lazaretto E. S. E. y 2 
S. ; 35-60 fathoms ; bottom mostly rocky, working on steep slope ; 
tangles ; June 3 ; sta. 75 ; 1 6 . 

Not before found in the lesser Antilles, although off Yucatan 
and Colombia. 

Batrachonotus fragosus Stimpson 

Bull. M. C. Z., vol. II, 1871, p. 122. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 
of fine coral fragments ; May 13 ; sta. 1;1 5. 

Euprognatha gracilipes A. Milne Edwards 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 58. 

2 miles due W. of Pelican Island, Barbados ; 80 fathoms ; bot- 
tom coarse sand ; May 17 ; sta. 13 ; 1 small 6 . 

Dredged by the "Blake" at Barbados in 69 to 76 fathoms. 

Arachnopsis filipes Stimpson 

Bull. M. C. Z., vol. II, 1871, p. 121. 

Barbados ; W. N. W. of Lazaretto ; N. N. W. of Pelican Island ; 
33 fathoms ; bottom rocky ; dredge ; May 27 ; sta. 51 ; 1 $ . 

Subfamily Pisinae 
Chorinus heros (Herbst) 
Rathbun, BuU. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 61. 

Pelican Island, Barbados ; tide pool ; May 11 ; 1 $ immature. 

Herbstia depressa Stimpson 
Plate II, fig. 4. 
Ann. Lye. Nat. Hist. N. Y., vol. VII, 1860, p. 57. 

6 



82 IOWA STUDIES IN NATURAL HISTORY 

Barbados ; May 15 ; 1 $ ovig. ; median length of carapace 14, 
width 12, length to tip of rostral horns 14.8 mm. 

Besides the tubercles on the carapace mentioned by Stimpson 
there are 4 tubercles or granules forming a transverse oblong on 
the branchial region, 2 of the granules near the inner angle of this 
region and the other 2 granules in a line posterior to the middle 
of the cardiac region. There is also a granule on the dorsal sur- 
face which forms a triangle with the 2 marginal spines at the 
widest part of the carapace. The row of spines on the merus of 
the cheliped is on its upper margin. 

Not before found south of St. Thomas. 

Lissa bicarinata Aurivillius 
Plate II, fig. 1. 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 64. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 
of fine coral fragments ; May 13 ; sta. 1 ; 1 $ ovig. ; carapace con- 
cealed dorsally by a calcareous coating which does not disguise 
the characteristic elevations. 

Subfamily Schizophrysinae 

Thoe puella Stimpson 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 63. 

Pillars of Hercules, Antigua; 2 6 3 $ (1 ovig.). 

Mithrax spinosissimus (Lamarck) 
The Lazy Crab Hughes, Nat. Hist. Barbados, 1750, p. 262, pi. 

XXV, fig. 1 (part: chelipeds and legs only). 
Mithrax spinosissimus Rathbun, Bull. U. S. F. C, vol. XX for 

1900, part 2, 1901, p. 66. 

Barbados : W. N. W. of Lazaretto ; N. N. W. of Pelican Island ; 
33 fathoms ; bottom rocky ; dredge ; May 27 ; sta. 51 ; 3 young. 

The largest of these, about 9 mm. long in the median line, 
shows a small spine on the basal antennal segment at the base of 
the next segment. 

Mithrax acuticornis Stimpson? 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 66. 



BARBADOS-ANTIGUA REPORTS 83 

Barbados ; May 22 ; 1 juv. with carapace less than 6 mm. long. 
Agrees in the main with M. acuticornis but the carapace is 
smoother than usual, the tubercles being fewer and lower. 

Mithrax pilosus Rathbun 

Bull. U. S. F. C., vol. XX for 1900, part 2, 1901, p. 66. 
Pillars of Hercules, English Harbour, Antigua ; 1 6 juv. 
Barbados ; 1 6 . 

Not before noted from Barbados, but occurring at Guadeloupe 
and Caracas. 

Mithrax hemphilli Rathbun 

Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, p. 69. 
English Harbour, Antigua; shore; 1 5. 

Mithrax verrucosus Milne Edwards 

Mag. Zool., vol. II, 1832, cl. VII, pi. IV and explanation. 

Pillars of Hercules, English Harbour, Antigua ; 1 6 , medium 
size. 

Fort Barclay, English Harbour ; July 9 ; 1 $ juv. 

English Harbour ; shore ; 1 $ juv. 

Pelican Island, Barbados; 1 6 juv. 

Not previously recorded from Barbados ; occurs at Guadeloupe, 
Martinique and on the coast of Brazil. 

Mithrax depressus A. Milne Edwards 

Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, p. 68. 
English Harbour, Antigua; shore; 1 6 medium, 1 juv. 

Mithrax pleuracanthus Stimpson 

Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, p. 68. 
Barbados; 1 6 juv. From coral heads; May 27; 2 6 1 9 
ovig., all small. 

Not recorded previously from Barbados, or farther south than 
Martinique. 

Mithrax caribbaeus Rathbun 
Plate III 

Proc. Biol. Soc. Washington, vol. XXXIII, 1920, p. 23. 
Barbados ; 2 $ , one rather large, the other middling small. 



84 IOWA STUDIES IN NATURAL HISTORY 

Length of carapace of larger $ on median line 53.5, extreme 
width 71 mm. Length of smaller $ 20.8, width 24.4 mm. 

Approaches M. hispidus in its large size and general shape, 
but the carapace is a little narrower, and the crenulation of the 
prehensile edges of the fingers in the gape persists in the old, 
while it disappears in old hispidus. 

Differs from all its allies in the arrangement of tubercles or 
tubercles and spines on the postero-lateral region. There is a 
postero-lateral spine in the young and middle-sized, which be- 
comes a tubercle in the old ; it is situated not far behind the spine 
at the lateral angle of the carapace, and forms the outermost of 
a transverse row of three, which is subparallel to another row of 
three tubercles. 

Barbados is the furthest east for this species ; it has been taken 
at Porto Rico, St. Thomas and Venezuela. 

Mithrax (Mithraculus) sculptus (Lamarck) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 71. 

Pillars of Hercules, English Harbour, Antigua; 14 6 6 $ (4 
ovig.). 

English Harbour ; 1 6 . 

Pelican Island, Barbados ; 4 6 . 

Barbados ; under sea anemone ; 3 $ 1 $ . 

M. sculptus is usually olivaceous, the color persisting in alco- 
hol. The 4 specimens taken from under sea anemones are an 
exception, as they are reddish brown, in alcohol. 

Mithrax (Mithraculus) coryphe (Herbst) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 71. 

Pillars of Hercules; English Harbour, Antigua; 6 6 7 $ (4 
ovig.). 

Ft. Barclay, English Harbour ; July 9 ; 1 6 . 

Pelican Island, Barbados; 2 6 1 9 . Tide pool; May 11; 1 5 
2 $ ovig. 

Barbados; 1 $. From coral head ; June 4 ; 1 6. Shore; 1 $ 
ovig. Under sea anemones; 3 6 5 9 (4 ovig.) 1 juv. 



BARBADOS-ANTIGUA REPORTS 85 

Mithrax (Mithraculus) forceps (A. Milne Edwards) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 

p. 70. 

1 mile S. of sta. 19, off Needham Point, Barbados ; 84 fathoms ; 

bottom rocky; sta. 20; 1 9 ovig. 
Barbados; 2 6 3 juv. 

Mithrax (Mithraculus) ruber (Stimpson) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 69. 

Pelican Island, Barbados; 1 6 1 9 juv. 

Needham Point, Barbados ; May 18 ; 3 6 1 9 immature. By 
diver; 1 6 . ' 

1 mile S. of sta. 19, off Needham Point; 84 fathoms; bottom 
rocky ; sta. 20 ; 2 6 3 9 . 

Okra Reef, Barbados ; May 13 ; 6 6 6 9 , all small. 

Barbados; shore; 1 9. May 15; 7 6 4 9 (2 ovig.) 2 juv. 
May 22 ; 1 6 . On old coral ; May 31 ; 1 6 1 9 immature. From 
«oral heads ; June 4 ; 4 6 1 9 ovig. 1 juv. 

Not heretofore known south of Guadeloupe. 

Mithrax (Mithraculus) cinctimanus (Stimpson) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 70. 

English Harbour, Antigua ; shore ; 1 9 , immature. 

Microphrys bicornutus (Latreille) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 72. 

Pillars of Hercules, English Harbour, Antigua; 10 $ 5 9 (2 
ovig.) 1 juv. 

English Harbour, Antigua; shore; 4 $ 2 9 (1 ovig.). 

Antigua; 1 9 ovig., with the slender, slightly divergent, in- 
curved horns figured by A. Milne Edwards, in Crust. Reg. Mex., 
1873, pi. XIV, fig. 2. 

Bathsheba, Barbados; 3 9 ovig., 1 juv. 

Pelican Island, Barbados ; May 11 ; 3 9 (1 ovig.) 1 juv. Tide 
pool ; May 11 ; 2 6 . May 13 ; 1 6 . 

Needham Point, Barbados; May 18; 1 9 juv. 

Barbados ; 4 6 2 9 ovig. Under sea anemones : 1 6 , soft shell. 



86 IOWA STUDIES IN NATURAL HISTORY 

Microphrys interruptus Rathbun 
Plate II, fig. 5. 

Proc. Biol. Soc. Washington, vol. XXXIII, 1920, p. 24. 

Fort Barclay, English Harbour, Antigua, July 9; 1 6 1 9 
juv. 

Needham Point, Barbados ; May 18 ; 1 6 . 

Known previously only from Cuba, the type locality. 

Measurements. — The male from Needham Point is only slightly 
larger than the type male; the male from Fort Barclay is con- 
siderably larger, total length of carapace 16.7, length of horns 
2.4, width of carapace without spines 13.6, with spines 13.3 mm. 
The carapace is widest above the bases of the first ambulatory 
legs where it exceeds slightly the width between the tips of the 
postero-lateral spines, which are above the bases of the second 
ambulatory legs. The egg-bearing female is about the same size 
as the male and is concealed beneath a mass of algae and other 
small organisms. 

Relationships. — M. bicornutus is very widespread and abun- 
dant, and a very variable species, but the form which I call inter- 
ruptus appears to be consistently different. It differs from bi- 
cornutus in being wider in proportion to its length, and wider 
across the orbits in proportion to its posterior width; in the 
greater prominence of the oblique branchial protuberances which 
are in line with the postero-lateral spine ; in the more transverse 
direction of the arch of four tubercles on the intestinal region; 
in the shorter and more transverse tooth at the antero-external 
angle of the basal antenna! segment, which is very little ad- 
vanced in dorsal view beyond the preorbital angle, and in ventral 
view gives the segment much greater relative width than in 
bicornutus; in the presence of a small but well-developed tooth 
or lobe on the infra-orbital margin, just outside the antennal 
segment ; this tooth is lacking in bicornutus. 

Stenocionops furcata (Olivier) 

The Horned Crab, Nat. Hist. Barbados, 1750, p. 266, pi. XXV, 

fig. 3. 
Stenocionops furcata Rathbun, Bull. XL S. F. C, vol. XX for 

1900, part 2, 1901, p. 73. 



BARBADOS-ANTIGUA REPORTS 87 

Barbados; in shore 200 yards from sta. 22 (*4 mile E. of 
sta. 21, in shore 400 to 500 yards) ; 35 fathoms; bottom rocky; 
tangles ; May 20 ; sta. 24 ; 1 6 . 

Macrocoeloma trispinosum (Latreille) 
Milne Edwards, Hist. Nat. Crust, vol. I, 1834, p. 336. 
English Harbour, Antigua ; shore ; 1 $ ovig., overgrown with 
sponge. 

Macrocoeloma trispinosum nodipes (Desbonne) 
In Desbonne and Schramm, Crust. Guadeloupe, 1867, p. 15, 
pi. V, fig. 13. 

English Harbour, Antigua ; shore ; 1 6 , 1 juv. 

Macrocoeloma subparallelum (Stimpson) 

Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 74. 

Bathsheba, Barbados; 1 9 ovig. 

Pelican Island, Barbados ; tide pools ; May 11 ; 1 $ immature. 

Barbados ; 1 $ . Shallow water ; under large anemone ; 1 $ 
ovig. 

The specimens are almost concealed by seaweed, aleyonarians 
and other foreign substances. 

First occurrence at Barbados; known from Guadeloupe and 
Old Providence. 

Macrocoeloma eutheca (Stimpson) 
Pericera eutheca Stimpson, Bull. M. C. Z., vol. II, 1871, p. 112. 

S. W. of Pelican Island, Barbados, 1 mile ; 38 fathoms ; bottom 
of fine coral fragments ; May 13 ; sta. 1 ; 1 6 . 

W. by N. of Telegraph Station, Barbados; y 2 mile off shore 
about edge of drop off ; 60-70 fathoms ; tangles ; June 1 ; sta. 66 ; 
1 9. 

First occurrence at .Barbados, though taken at St. Croix and 
Colon. 

Macrocoeloma intermedium Rathbun 
Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, p. 75. 
Off Lazaretto, Barbados ; 20 fathoms ; bottom rough ; tangles ; 
June 6; sta. 87; 1 $ immature. 

First record at Barbados, though taken at Dominica and Colon. 



88 IOWA STUDIES IN NATURAL HISTORY 

PlCROCEROIDES TUBULARIS MierS 

Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, p. 76. 

Shoal Bank, Barbados, about 3 miles W. of Needham Point; 
20-40 fathoms ; sponge bottom ; sta. 101 ; 1 juv. 

Not before taken near Barbados, but off St. Thomas and the 
coast of Brazil. 

Pitho mirabilis (Herbst) 
Rathbun, Bull. U. S. F. C, vol. XX for 1900, part 2, 1901, 
p. 78. 

Pillars of Hercules, English Harbour, Antigua ; 1 $ . 



BIBLIOGRAPHY 

Desbonne and Schramm. Crustaces de la Guadeloupe d'apres 
un manuscrit du Docteur Isis Desbonne compare avec les 
eehantillons de crustaces de sa collection et les dernieres publi- 
cations de MM. Henri de Saussure et William Stimpson. l re 
partie. Brachyures. Basse-Terre. 1867. [Edited by Alphonse 
Schramm.] 

Edwards, A. Milne. Reports on the Results of Dredging under 
the Supervision of Alexander Agassiz, in the Gulf of Mexico, 
and in the Caribbean Sea, 1877, 78, 79, by the U. S. Coast 
Survey Steamer "Blake", Lieut.-Commander C. D. Sigsbee, 
U. S. N., and Commander J. R. Bartlett, U. S. N., Command- 
ing. VIII. Etudes preliminaires sur les Crustaces. 

Bull. Mus. Comp. Zool. at Harvard College, vol. VIII, No. 1, 
Cambridge, 1880, pp. 1-68, pis. I and II. 

Edwards, A. Milne. Reeherches Zoologiques pour servir a This- 
toire de la faune de TAmerique Centrale et du Mexique, 5 e 
partie, Paris, 1881. Etudes sur les Xiphosures et les Crustaces 
de la Region Mexicaine, 1873-1880. 368 pp., 61 pis. 

Edwards, A. Milne, and E. L. Bouvier. Reports on the Results 
of Dredging under the Supervision of Alexander Agassiz, in 
the Gulf of Mexico (1877-78), in the Caribbean Sea (1878- 
79), and along the Atlantic Coast of the United States (1880), 
by the U. S. Coast Survey Steamer "Blake", Lieut.-Com. C. D. 
Sigsbee, U. S. N., and Commander J. R. Bartlett, U. S. N., 
Commanding. XXXIX. Les Dromiaees et Oxystomes. 

Mem. Mus. Comp. Zool. at Harvard College, vol. XXVII, 
No. 1, Cambridge, 1902, pp. 1-127, pis. I-XXV. 

Edwards, H. Milne. Sur les Crustaces du genre Mithrax. 
Mag. Zool., vol. II, Paris, 1832, classe VII, pis. I-V. 

Edwards, H. Milne. Histoire Naturelle des Crustaces, vol. I, 
Paris, 1834, xxxv and 468 pp. 

7 89 



90 IOWA STUDIES IN NATURAL HISTORY 

Hughes, Griffith. The Natural History of Barbados. London, 
1750. Book IX. Of Crustaceous Animals. Pp. 261-266, pi. 
XXV. 

Rathbun, Mary J. List of the Decapod Crustacea of Jamaica. 
Ann. Inst. Jamaica, vol. I, No. 1, 1897, pp. 1-46. 

Rathbun, Mary J. The Brachyura of the Biological Expedi- 
tion to the Florida Keys and the Bahamas in 1893. 

Bull. Lab. Nat. Hist. State Univ. Iowa, vol. IV, 1898, pp. 
250-294, pis. I-IX. 

Rathbun, Mary J. The Brachyura and Macrura of Porto Rico. 
Bull. U. S. Fish Comm., vol. XX for 1900, part 2, 1901, pp. 
1-137, pis. I and II. 

Rathbun, Mary J. The Grapsoid Crabs of America. 

Bull. U. S. Nat, Mus., No. XCVII, 1918, pp. 1-461, pis. 
I-CLXI. 

Rathbun, Mary J. New species of Spider Crabs from the 
Straits of Florida and Caribbean Sea. 

Proe. Biol. Soc. Washington, vol. XXXIII, 1920, pp. 23-24. 

Stimpson, William. Notes on North American Crustacea, Nos. 
I and II. 

Ann. Lye. Nat. Hist. N. Y., vol. VII, New York, pp. 49-93 
(1859), pp. 176-246 (1860), pis. I, II and Y. 

Stimpson, William. Preliminary Report on the Crustacea 
dredged in the Gulf Stream in the Straits of Florida. 

Bull. Mus. Comp. Zool. at Harvard College, vol. II, Cam- 
bridge, 1871, pp. 109-160. 



EXPLANATION OF PLATES 

Plate III and plate II, fig. 1, are from photographs loaned by 
the U. S. National Museum. The other photographs on plate II 
were made by Mr. Clarence R. Shoemaker and retouched by Mr. 
Seward H. Rathbun who made the drawings on plate I. 

Plate I 
Pilumnus barbadensis, 9 , Barbados 
Fig. 1. Major chela, X 8. 

2. Minor chela, X 9.4. 

3. An ambulatory leg, X 8. 

4. Carapace, with eyes and antennae, X 7. 

Plate II 

Fig. 1. Lissa bicarinata, $ , Cat. No. 24120, U. S. N. M., dorsal 
view, carapace 9.6 mm. long. 

2. Xanthias granulimanus, $ , Cat. No. 20052, U. S. N. M., 
ventral view, X 3. Carapace 9.2 mm. wide. 

3. Same, dorsal view, X 3. 

4. Herbstia depressa, 9 , Barbados, X 2 2-3. 

5. Microphrys interruptus, 6 , Fort Barclay, X 3. Cara- 
pace, including horns, 16.7 mm. long. 

Plate III 

Mithrax caribbaeus, 6 holotype, Cat. No. 50363, U. S. N. M., 
dorsal view, carapace, including horns, 66.3 mm. long. 



PLATE I 








PLATE II 





PLATE III 







REPORT ON THE TANIDACEA AND 

ISOPODA 

Collected by the Barbados- Antigua Expedition 
from the University of Iowa in 1918 

Pearl L. Boone 

Aid, Division of Marine Invertebrates, U. S. National Museum 



The Isopod Crustacea of the Barbados-Antigua Expedition 
conducted by the State University of Iowa during the summer 
of 1918, though a small collection, has proven quite interesting. 
Of the six species represented, one, Exosphaeroma nuttingi, is 
new to science ; another, Porcellia parvicornis Richardson, repre- 
sents the second record of this species, which was described from 
a single specimen secured in the Bermudas in 1901. 

A single representative of the Tanaidacea was taken ; namely, 
Apsuedes espinosus Moore. 

An annotated list of the material collected and discussion of 
the new species is herewith presented. The drawing of the latter 
was made by Mr. Seward H. Rathbun under my direction. 

TANAIDACEA 

Family Apseudidae 

Genus Apseudes Leach 

Apseudes espinosus Moore 

Apseudes espinosus Moore, Bull. U. S. Fish Commission XX, 

pt. 2, 1902, pp. 165-166, pi. 7, figs. 1-6. Richardson, Bull. 54, 

U. S. Nat. Mus., 1905, p. 38, figs. 34 a-f. 

One male specimen of this species was collected at Station 1, 
Barbados, 1918, and is in the collection of the State University 
of Iowa. 

Moore described the type from a female, taken by the U. S. 
Bureau of Fisheries steamer "Fish Hawk", at Station 6079, off 
St. Thomas, Porto Rico, 20 fathoms, on coral bottom. 

91 



92 IOWA STUDIES IN NATURAL HISTORY 

Representatives of this species from the following localities 
are in the collections of the U. S. National Museum ; from among 
algae, No Name Key, Fla. ; off the Customs House, Mayaguez, 
Porto Rico, Station 6651, in 4-6 fathoms ; also from Station 6090 
off Culebra Island, S. "W. Culebrita, Porto Rico, in 16 fathoms. 

ISOPODA 
Family Cirolanidae 

Genus Cirolana Leach 

ClROLANA MAYANA Ives 

Cirolana may ana Ives, Proc. Acad. Nat. Sci. Phil., 1891, pp. 
186-187, pi. VI, fig. 6, figs. 3-10.— Richardson, Bull. 54, U. S. 
Nat. Mus., 1905, p. 87, fig. 66. 

A single adult specimen, collected in sand, June 2, 1918, 
Barbados, was secured and is in the collections of the State Uni- 
versity of Iowa. 

Type locality: Port of Silam, Yucatan, 3 specimens. Subse- 
quent records for this species are: Boqueron Bay and Culebra, 
Porto Rico (H. F. Moore). Santa Marta, U. S. Colombia (Rich- 
ardson). Brandon's, Barbados Beach; San Francisco Bay, Low- 
er California (Richardson, 1905). I doubt the validity of this 
last locality. 

There are no specimens of Cirolana may ana Ives in the collec- 
tions of the U. S. National Museum. 

Cirolana parva Hansen 

Cirolana parva Hansen, Vidensk. Selsk., Skr. (6), V, 1890, pp. 
340-341, pi. 2, figs. 6-6b, pi. 3, figs. 1-ld. Richardson, American 
Naturalist, vol. 34, 1900, p. 217. Proc. U. S. Nat. Mus., vol. 23, 
1901, p. 514. Bull. 54, U. S. Nat. Mus., 1905, p. Ill, figs. 93-94. 
Moore, Bull. U. S. Fish Com., 20, pt. 2, 1902, p. 167, pi. 8, figs. 
6-8. 

Sixteen specimens from Pelican Island, Barbados, were col- 
lected June 13, 1918, 14 of which are in the collection of the 
State University of Iowa and two in the U. S. National Museum, 
Cat. No. 53882. 

One specimen, taken with electric light at English Harbour, 
one taken at dredging station 1, Barbados, another from Station 



BARBADOS-ANTIGUA REPORTS 93 

11, Barbados, also one labeled "Barbados, May 15, 1918/ ' are in 
the collections of the State University of Iowa. 

Type localities: — Hansen states that he has examined repre- 
sentatives of the species from the following localities : St. Thomas, 
West Indies, 5 specimens (Krebs, 1867) ; St. Croix, West Indies, 
2 specimens (Oersted) ; West Indies, 1 specimen (Kroyer) ; 
without locality but probably West Indies, 1 specimen; 25° 
N. B., 34° V. L., 2 specimens (Hygom) ; Samoa Islands, 1 speci- 
men (Mus. Godeffroy). This last he offers with hesitation and 
fears the locality with specimen may be wrong, but states the 
specimens are identical with the West Indian material. 

In addition, representatives of this species from the following 
localities are in the collections of the U. S. National Museum ; 
between the delta of the Mississippi and Cedar Keys, Florida, 
Stations 2369-74, 25-74 fathoms depth; Station 2406, Gulf of 
Mexico, Lat. N. 28° 46', Long. W. 84° 49', 26 fathoms; Station 
7293, Gulf of Mexico, off Northwest Channel, 7% fathoms depth, 
off Biscayne Key, Florida, 16-34 ft. depth; Grassy Key Lake, 
off Grassy Key, Florida, Station 7431, 8 feet depth, No Name 
Key, Florida, banks, low tide ; off Knights Key Channel, N. E. 
Bahia Honda Key, Florida, Station 7411, 10 ft. depth ; Pigeon 
Key Lake, Florida, Station 7404, 10y 2 ft. depth; Key West, 
Florida, among algae, below low tide ; Key West, Florida ; speci- 
mens from sponges, Lisbon Reef, Andros Island, Bahamas; in 
algae (Panicillus capitatus), Georgetown, Great Exuma, Ba- 
hama, shallow water about the keys, Esperanza, Cuba; from 
mangrove roots, Boque Islands, Montego Bay, Jamaica; Maya- 
guez, Porto Rico; from Porto Real, Porto Rico; Ponce, Porto 
Rico; Playa de Ponce, Porto Rico, on lighthouse reef, Arroyo, 
Porto Rico; Fajardo, Porto Rico; Boqueron Bay, Porto Rico; 
Ensenada Honda, Culebra, Porto Rico; off St. Thomas, Virgin 
Islands, U. S., Station 6080, 20 fathoms depth; St. Thomas, 
Virgin Islands, U. S. 

Family Excorallanidae 

Excorallana Stebbing 2 
Excorallana subtilis (Hansen) 
Corallana subtilis Hansen, Vidensk. Selsk. Skr. (6), V, 1890, 

1 See Hansen for characters of family, Vidensk. Selsk. Skr. (6), V, 1890, pp. 311- 
313, 317, 376, Kjobenhavn. 

2 Fauna and Geography of the Maldive and Laccadive Archipelagoes, II, Pt. 3, 
1904, p. 704. 

8 



94 IOWA STUDIES IN NATURAL HISTORY 

pp. 382, 383, pi. 7, figs. 3~3c, Richardson, Proc. U. S. Nat. Mus., 
XXIII, 1901, p. 519. 

Excorallana subtilis Richardson, Bull. 54, U. S. Nat. Mus., 
1905, p. 146, fig. 130 a-d. 

A single immature specimen of this species was taken at Okra 
Reef, Barbados, May 13, 1918, and is in the collections of the 
State University of Iowa. 

Hansen described this species from a single young female spe- 
cimen in the process of ecdysis labelled "St. Thomas, Krebs, 
Aug. 24, 1858", which is in the Copenhagen Museum. 

Two male specimens collected in the harbor of Key West, 
Florida, by Dr. Edward Palmer, in 1884, Cat. No. 13581, are in 
the collections of the U. S. National Museum. These specimens 
agree with Hansen's description except that they lack the two 
large tubercles at the base of the abdomen, but it must be re- 
called that the type was an immature female in process of 
ecdysis. 

Excorallana oculata (Hansen) 

Three specimens of this species were collected with electric 
light at English Harbour, Barbados, 1918; two of these are in 
the collections of the State University of Iowa, the third is in the 
collections of the U. S. National Museum, Cat. No. 53886. 

Hansen described the species from two specimens collected in 
the West Indies, by Krebs, 1866, and deposited in the Copen- 
hagen Museum. 

Three specimens, collected by the steamer " Albatross' ' at Sta- 
tion 2758, in 20 fathoms of water, off Cape St. Roque, Brazil, 
are in the U. S. National Museum. 

Family Cymothoidae 

Genus Anilocra Leach 
Anilocra laticauda Milne Edwards 

Anilocra laticauda Milne Edwards, Hist. Nat. Crust. Ill, 1840, 
p. 259. 

Anilocra mexicana Saussure, Rev. Mag. Zool., 1857, p. 505. 

Anilocra leachii (Kroyer) Sehiodte & Meinert, Naturhistorisk 
Tidsskrift (3), XIII, 1881-83, pp. 126-131, pi. IX, figs. 1-3. 
Richardson, American Naturalist, XXXIV, 1901, p. 528. — 



BARBADOS-ANTIGUA REPORTS 95 

Moore, Report XJ. S. Com. Fisheries XX, Pt. 2, 1902, p. 172, pi. 
X, figs. 3-4. Richardson, Bull. 54, U. S. Nat. Mus., 1905, p. 227, 
fig. 230. 

Two adult and four young specimens of this well-known fish 
parasite were collected May 14, 1918, near Pelican Island, Bar- 
bados, and are in the collections of the State University of Iowa. 

The type locality of the species was described "Habitat la mer 
des Antilles". 

The species has been recorded as parasitic on Ocyurus chrys%~ 
rus, Bathystoma rimator, Haemulon plumieri, H. arcuatum, 
Upeneus martinicus, and Abudefduf saxtalis from a series of 
localities establishing a geographic range from Maryland to the 
Straits of Magellan. 

The representatives of the species from the following localities 
are in the collections of the U. S. National Museum : on " Grunt/ ' 
Jewfish Bush Lake, Florida; "on fish," Key West, Florida; 
Arroyo and Vieques, Porto Rico; West End Santa Lucia Bay, 
Cuba ; Cape Ca jon, Cuba ; on parrot-fish, Montego Bay, Jamaica ; 
on eye of yellow-tail, Ocyurus chrysurus, Montego Bay, Jamaica ; 
''from angle of mouth (external) of Bathystoma rimator 7 % Ja- 
maica; from small yellow-tail, Snug Harbor, Montego Bay, Ja- 
maica ; on head of Haemulon arcuatum, Cozumel, Yucatan ; Cat. 
No. 7660, on fish, St. Thomas, West Indies; Buck Island, near 
St. Thomas, West Indies ; 1 specimen on red-fish, St. Croix, West 
Indies; on Abudefduf saxatilis, Toso Point, Canal Zone, Panama; 
on A, saxatilis, Colon Reef, Panama; Cat. No. 20481, 2 speci- 
mens, Porlamar, Margarita Island, Venezuela; Rio de Janeiro, 
Brazil. 

Genus Cymothoa Fabricius 

Cymothoa oestrum (L.) 

Oniscus oestrum Linnaeus, Syst. Nat., 10th Ed., I, 1758, p. 
636, No. 2; Fauna suecica, 2nd ed., 1761, p. 499, No. 2053; Syst. 
Nat., 12 ed., I, 1767, pt. 2, p. 1059, No. 2. 

Asellus oestrum Olivier, Encycl. Method. IV, 1789, p. 253. 

Cymothoa oestrum Fabricius, Entom. Syst. II, 1798, p. 505, 
No. 6,— Leach, Trans. Linn. Soc. London, XI, 1815, p. 372 ; Diet. 
Sci. Nat. XII, 1818, p. 362. 

Cymothoa dufresnei Leach, Diet. Sci. Nat. XII, 1818, p. 352. 



96 IOWA STUDIES IN NATURAL HISTORY 

Cymothoa immersa Say, Journ. Acad. Nat. Sci. Phila., I, 1818, 
pp. 399-400. 

Cymothoa oestrum Desmarest, Consid. Gen. Crust., 1825, p. 
309, pi. 47, figs. 6-7, Miers, Proc. Zool. Soc., 1877, pp. 671-672,— 
Sehiodte and Meinert, Naturh. Tidsskr. (3), 14, 1883-84, pp. 
271-279, pi. 8, figs. 5-13. Richardson, American Naturalist, 34, 
1900, p. 221; U. S. Nat. Mus., 23, 1901, p. 530; Bull. 54, U. S. 
Nat. Mus., 1905, p. 254, fig. 263. 

Four adult specimens of this species were found parasitic on 
the tongue of " horse-eye cavalli" (fish), May 28, 1918, Bar- 
bados. About twenty-five very young of the second stage were 
collected in sand, Barbados, June 2, 1918. One of the adults is 
in the collections of the U. S. National Museum, Cat. No. 53883. 
The remainder are in the collections of the State University of 
Iowa. 

The type locality of this well-known parasite was recorded 
"Habitat in Oeeano". 

It has been recorded as taken from the following hosts : Caranx 
latus, C. ruber, "jack-fish", from branchial cavity; "red Fish" 
stomach, in the tongue of Scombroid fishes, parasitic on the 
mouth of Priacanthus arenatus and Trachurops crumenopthal- 
mus; Sparisoma abilgaardi, Cynocion ciorchus, on Strombus gi- 
ganteus, the various localities cited giving a geographic range 
from the shore of Virginia to the southern shores of the Carib- 
bean Sea, also the coast of Peru. 

The representatives of this species from the following localities 
are in the collections of the U. S. National Museum: from the 
mouth of Caranx ruber, Tortugas, Florida ; Key West, Florida ; 
parasitic on Trachurops crumenopthalmus, and on Priacanthus 
arenatus, Bermuda; Cat. No. 28678, from the "stomach of red- 
Fish", near Barbados; from parrot-fish, Sparisoma abUgaardi, 
Montego Bay, Jamaica; from the branchial cavity of jack fish, 
Caranx species, Jamaica; Curasao, Feb., 1884; from mouth of 
fish, St. Thomas, Virgin Islands, U. S. ; 1 young male specimen 
on the gills of Cynocion ciorchus, Colon market, Colon, Canal 
Zone, Panama; Swan Island, Caribbean Sea. 



BARBADOS-ANTIGUA REPORTS 97 

Family Sphaeromidae 

Sphaerominae hemibranchiatae 

Exosphaeroma nuttingi new species 

Figures 1-2 

Body elongate-ovate, smooth, ground color creamy yellowish, irregularly 
mottled with fine black splotches. 

Head two-thirds as long as wide with frontal margin produced to a 
median point on either side of which it is moderately excavated and thence 
recurvate for the reception of the antennal joints. Eyes large, round, occu- 
pying the entire postlateral area of the head. First antennae with the basal 
article elongate, broad, flattened, second article half as long as the first, 
very convex; the third article slender, cylindrical, two- thirds as long as the 
first, and a flagellum of eight slender subequal articles and extends almost 
to the posterior margin of the first thoracic segment. The second antennae 
have the first and second joints short, subequal, the third and fourth joints 
each slightly longer than the second, the fifth joint slightly longer than the 
fourth and a flagellum of eleven tapering subequal articles which extends 
almost to the posterior margin of the third segment. The maxillipeds have 
the lobes of the distal four joints much produced. 

The first thoracic segment is slightly longer than any of the others which 
are subequal, the epimera are easily distinguished and have their respec- 
tive lateral margins rounded and sculptured. The seven pairs of legs are 
similar, subequal, irregularly, sparsely set with spines along the inner side. 

The abdomen has the first thoracic segment a trifle longer than the sev- 
enth thoracic segment and bears three transverse lines indicating the coales- 
cence of four segments, the terminal segment is convex, domelike, with the 
posterior marginal area on a slightly lower plane than the central area; the 
posterior margin is broadly rounded, the extreme median area has a broad 
shallow excavation on the ventral surface, the distal termination of this 
ehannel causes a vague almost invisible truncation of the dorsal margin. 
The uropoda have the peduncle rounded, knob-like, its articulation with the 
inner branch being difficult to distinguish; the inner branch has the inner 
lateral margin relatively straight, the outer margin broadly rounded, the 
distal margin crenulate; the outer blade is four-fifths as long as the inner 
blade and is broadly oval with its posterior margin crenulate. 

Pleopoda one and two are subequal, similar, fringed; pleopoda three has 
the exopod two- jointed; pleopoda four and five have the endopods thick, of 
fleshy aspect, with deep, essentially transverse folds, the exopods submem- 
braneoua and rather pellucid, two jointed. 

The present species may be distinguished from Exosphaeroma crenulatum 
Uichardson* by the faet that it has three transverse lines on the first ab- 
dominal segment indicating the coalescence of four segments; these lines 



* Exosphaeroma crenulatum Richardson, Bull. 54, U. S. Nat. Mus., 1905, p. 298, 
figs. 317-318. 



98 IOWA STUDIES IN NATURAL HISTORY 

are quite differently placed from the two lines of coalescence of Exospliae- 
roma crenulatnm; the posterior margin of the telson is different, the uropoda 
have both blades slightly crenulate only on the distal end, and the lobes of 
the second, third and fourth joints of the palp of the maxilliped are much 
produced. 

The holotype and eleven paratypes are in the collections of the 
State University of Iowa. Six additional paratypes are in the 
collections of the U. S. National Museum, Cat. No. 53884. All 
were collected from among the spines of a sea-urchin, Barbados. 
Named for Professor C. C. Nutting. 

ONISCOIDEA 

Family Oniscidae 

Genus Pobcellio Latreille 

Porcellio parvicornis Richardson 

Porcellio parvicornis Richardson, Trans. Conn. Acad. Sciences, 
XI, 1902, p. 302, pi. 40, fig. 57.— Bull. 54, U. S. Nat. Mus., 1905, 
p. 616, fig. 667. 

Three specimens of this species were collected at Indian River, 
Barbados, May 21, 1918. Two specimens are in the collections 
of the State University of Iowa and one in the U. S. National 
Museum, Cat. No. 53885. These represent the second record of 
this species, which was described from a single specimen collected 
by Prof. A. E. Verrill at the Bermudas in 1901, and deposited 
in the collections of Peabody Museum, Yale University. 

EXPLANATION OF PLATE 

Pig. 1. Exosphaeroma nuitingi new species, type. 
Fig. 2. Exosphaeroma nuitingi maxilliped. 



PLATE I 




X l t'-'£*^ / - 


rl ■ •»* '^ 


& "J*vi 








•m, 





( OF ;i 



REPORT ON THE AMPHIPODS 

Collected by the Barbados- Antigua Expedition 
from the University of Iowa in 1918 

Clarence R. Shoemaker 

Aid, Division of Marine Invertebrates, U. S. National Museum 



The Amphipod collection of the expedition is represented by 
191 specimens which are included in sixteen species. The rec- 
ords are all new for Barbados and four of the species (Ampelisca 
lobata, Lembos coneavus, Chevalia aviculae, and Ampithoe inter- 
media) are reported for the first time from the east coast of 
America. 

1. Lysianopsis alba Holmes 

Station 1, one mile S. W. of Pelican Island, Barbados, 

May 13, 1918, 38 fms. 2 specimens 

This species was described by S. J. Holmes in 1905 from 
Woods Hole, Mass. It was reported by Arthur S. Pearse in 1912 
from Gulf of Mexico. J. B. Henderson and Paul Bartseh found 
it off Cape San Antonio, Cuba, in 1914, and in 1915 it was col- 
lected by myself at St. Thomas, W. I. 

2. Ampelisca lobata Holmes 

Station 1, one mile S. W. of Pelican Island, Barbados, 
May 13, 1918, 38 fms. 1 specimen 

This is the first report of the occurrence of this species upon 
the east coast of North America, the species having been de- 
scribed by S. J. Holmes off San Nicolas Island, Southern Cali- 
fornia, in 1908. 

3. Amphilochus, species 

Pelican Island, Barbados, May 13, 1918. 2 specimens 

These specimens are too imperfect for identification. 

4. Leucothoe spinicarpa (Abildgaard) 

Pelican Island, Barbados, May 13, 1918. 1 specimen (immature) 
This species is found throughout the Arctic Ocean, on the 

99 



100 IOWA STUDIES IN NATURAL HISTORY 

coast of Norway, northern coast of Europe, British Isles, Azores, 
Bermuda, Mediterranean, Ceylon, Seychelles, British East Af- 
rica, Red Sea, McMurdo Sound (Antarctic), South Georgia, 
Cape Agulhas, South Orkneys, East coast of North America, 
Gulf of Mexico, St. Thomas, Jamaica, Cuba, and South Africa. 
This is the first mention of its occurrence at Barbados. Leu- 
cothoe spinicarpa frequently lives commensal in the branchial 
chamber of Aseidians. 

5. Batea catharinensis Muller 

Pelican Island, Barbados, May 13, 1918. 3 specimens 

Batea catharinensis was discovered at Desterro, Brazil, and in 
1865 Fritz Muller created the genus for it. No members of the 
genus were again met with until 1900 when some specimens were 
found near Woods Hole, Mass., and described by S. J. Holmes as 
Batea secunda. The specific differences which this author points 
out, however, are very slight and the two species will probably 
prove to be the same. Batea catharinensis has also been found at 
Chesapeake Bay, Skull Creek, S. C, mouth of May River, S. C, 
and now at Pelican Island, Barbados. 

6. PONTOGENEIA VERRILLI Kunkel 

Pelican Island, Barbados, May 13, 1918. 1 specimen 

In 1910 B. W. Kunkel described this species from Bermuda 
and this single specimen now from Barbados marks the second 
record. 

7. Maera inaequipes (A. Costa) 

Pelican Island, Barbados, May 13, 1918. 46 specimens 

This species has been reported from the Azores, Mediterra- 
nean, Bermuda, Cuba, and South Africa ; and the present record 
is the first for Barbados. 

8. Elasmopus rap ax A. Costa 

Pelican Island, Barbados, May 13, 1918. 48 specimens 

This species has been reported from Norway, British Isles, 
France, Azores, Bermuda, Gulf of Mexico, Jamaica, Cuba, and 
now for the first time from Barbados. 



BARBADOS-ANTIGUA REPORTS 101 

9. Orchestia platensis Kroyer 
Station 1, one mile S. W. of Pelican Island, Barbados, 

May 13, 1918, 38 fms. 1 specimen 

Beach near Pelican Island, Barbados, May 27, 1918. 10 specimens 

This Amphipod has been found upon the beaches of nearly all 
the temperate and tropical regions of the earth ; this, however, is 
the first record for Barbados. 

10. Lembos concavus Stout 
Pelican Island, Barbados, May 13, 1918. 17 specimens 

In 1913 Vinnie Ream Stout described this species from Laguna 
Beach, California. The specimens taken at Barbados are smaller 
but agree very well with the description. This is the first ap- 
pearance of this species on the east coast of America. 

11. Eurystheus lin a Kunkel 
Pelican Island, Barbados, May 13, 1918. 35 specimens 

The first specimens of this species were found at Bermuda in 
1903 and described by B. W. Kunkel in 1910. Specimens have 
been taken also at Tortugas, Florida, and Porto Rico and this 
record from Barbados extends the range much to the south. 

12. Eurystheus, species 
Station 1, one mile S. W. of Pelican Island, Barbados. 

May 13, 1918, 38 fathoms. 1 specimen 

This single, female specimen is in too imperfect a condition 
for specific identification. 

13. Chevalia aviculae Walker 
Pelican Island, Barbados, May 13, 1918. 18 specimens 

This species was found by Herdman and Hornell at Ceylon in 
pearl oyster washings, and described by A. O. Walker in 1904. 
It was later taken at Saya de Malha Bank, Cargados Islands, 
and South Africa. Walker thinks this is probably a tube-build- 
ing species but nothing yet is known of its habits. The species 
described by Arthur S. Pearse as Chevalia mexicana in 1912 
from the Gulf of Mexico will probably prove to be the same as 
Walker's species. This is the first record for Barbados. 



102 IOWA STUDIES IN NATURAL HISTORY 

14. Amphithoe intermedia Walker 
Barbados, under sea anemones. 3 specimens 

A. 0. Walker described this species from Ceylon in 1904, and 
in 1905 he reported it from the Maldive Islands. Chevreux in 
1907 reported it from the Tuamotu Islands. In 1909 A. 0. 
Walker recorded it from Praslin Reef, Zanzibar, and Red Sea. 
The specimens from Barbados agree with those figured by Chev- 
reux in having the broad rounded lobe on the lower, anterior 
corner of the second joint of the second gnathopods. 

15. Orubia compta (Smith) 
Barbados, June 4, 1918 (from coral heads). 1 specimen 

This species was described by S. I. Smith in 1873 and was said 
to range from North Carolina to Cape Cod. In 1912 Arthur S. 
Pearse reported it from Harbor Key and Key West, Florida. 
The present record is the first from Barbados. 

16. Podocerus brasiliensis (Dana) 
Pelican Island, Barbados, May 13, 1918. 1 specimen 

This is a tropical Atlantic species which heretofore has been 
reported only from Rio Janeiro and Antigua. 



REPORT ON THE ECHINOIDEA 

Collected by the Barbados- Antigua Expedition 
from the University of Iowa in 1918 

Hubert Lyman Clark 

Museum of Comparative Zoology, Cambridge 



The collection of Echinoidea made by the party from the 
University of Iowa, which under the leadership of Professor 
C. C. Nutting, visited Barbados and Antigua in the summer of 
1918, is not a large one but it represents well the typical littoral 
West Indian fauna. The 229 specimens belong to 18 species, all 
but two of which are known, characteristic forms of the Carib- 
bean region. The two exceptions are notable indeed, for each 
represents a genus not hitherto reported from the West Indies: 
one (Pseudoboletia) is recorded from the eastern Atlantic (As- 
cension Island) and the other (Centrostephanus) occurs on the 
western coast of Mexico. 

Of the 229 specimens, 178 belong to three very common West 
Indian species, Eckinometra lucunter, Echinoneus cyclostomus 
and Brissus brissus. The equally common species, Centrechinus 
antillarum, Tripneustes esculentus and Lytechinus variegatus, 
are represented by very few specimens, presumably because their 
large size made extensive series undesirable and their common- 
ness made such series unnecessary. These six common species 
occurred at both Barbados and Antigua. The only other echini 
found at the latter island were Eucidaris tribuloides and Cly- 
peaster rosaceus, which are also common and widespread species. 
But no Clypeaster was taken at Barbados. 

The 18 species fall naturally into two divisions, those which 
occur along shore, or on reefs easily accessible at low tide, and 
those which are gotten only by dredging, trawling or the use of 
tangles. The former are the strictly " littoral' ' group; the latter 
belong rather to the ' ' continental ' ' fauna ; of course members of 
the littoral group are often taken in deeper water, sometimes 

103 



104 IOWA STUDIES IN NATURAL HISTORY 

down to 50 or even 100 fms., but the species of the continental 
group do not seem to ever come up into the very shallow water. 
The following list shows the echini of the present collection 
which belong to the strictly littoral group: 

Eucidaris tribuloides Echinometra lucunter 

Centrechinus antillarum Clypeaster rosaceus 

Lyt echinus variegatus Mellita sexiesperforata 

Tripneustes esculentus Echinoneus cyclostomus 

Brissus brissus 

In a recent study of the littoral eehinoderms of the West 
Indies (1919, Publ. 281, Carnegie Inst., pp. 51-74), I have re- 
corded 7 of these 9 species from Barbados and 6 from Antigua, 
relying mainly on the field notes of Dr. W. K. Fisher who was a 
member of the Iowa party. The present collection adds Lyte- 
chinus variegatus to the fauna of Barbados and Clypeaster rosa- 
ceus and Echinoneus cyclostomus to the fauna of Antigua. 

Of the remaining nine species, eight unquestionably belong to 
the continental groups. The ninth, the unique Pseudoboletia, 
may possibly prove to be littoral but the depth at which it was 
found is not recorded. The nine species are: 

Stylocidaris affinis Lytechinus callipeplus 

Tretocidaris bartletti Lytechinus euerces 

Coelopleurus floridanus Genocidaris maculatus 

Centrostephanus rubicingulus Pseudoboletia occidentalis 

Agassizia excentrica 

Excepting only the two new forms, all these species were taken 
by the " Blake" near Barbados, and also near Dominica, Mont- 
serrat or St. Cruz. Hence their occurrence in the present collec- 
tion was quite to have been expected. There are no specimens 
however of any of them from Antigua, all having been taken off 
the southwest coast of Barbados in 25-100 fms. But practically 
no dredging was done at Antigtia except in the shallow harbors 
and bays, owing to the high seas outside those sheltered areas. 

LIST OF SPECIES 

EUCIDARIS TRIBULOIDES 

Cidarites tribuloides Lamarck, 1816. Anim. s. Vert., 3, p. 56. 



BARBADOS-ANTIGUA REPORTS 105 

Cidaris tribidoides A. Agassiz, 1872. Rev. Ech., p. 253 ; pi. Id 
and pi. II, figs. 1-3. 

Eucidaris tribulaides Doderlein, 1887. Jap. Seeigel, p. 42. 

There are three specimens of this well-known sea-urchin at 
hand; one, 38 mm. in diameter with primary spines 35-38 mm. 
long, from Falmouth Harbor, Antigua ; one 25 mm. with spines 
of about that length, from Carlisle Bay, Barbados, 30 f ms. ; and 
an interesting young individual, about 16 mm. in diameter, with- 
out a locality label but apparently from Barbados. This last 
specimen has the primary spines very stout (15 mm. long by 2.5 
mm. in thickness) and more or less flaring at tip. Owing to the 
unusually well developed longitudinal ridges, the tips are quite 
florescent. The peculiarities of this specimen are probably asso- 
ciated with its youth, as the wear on the spines during maturity 
and their tendency to become the abiding-place of bryozoans and 
other fixed animals in their old age usually obliterate such fea- 
tures as are here noted. 

STYLOCIDARIS AFFINIS 

Cidaris affinis Philippi, 1845. Arch. Naturg., jhg. 11, 1, p. 351. 
See Mortensen, 1903, Ingolf Ech., pt. 1, pi. I, fig. 1. 

Dorocidaris papillata A. Agassiz, 1872. Rev. Ech., p. 254 (in 
part) ; pi. I, fig. 5. 

Stylocidaris affinis Mortensen, 1909. Ech. Deutsch. Siidpolar- 
Exp., p. 52. 

All of the 5 specimens of this cidarid in the present collection 
are young, the largest being scarcely half grown. The diameter 
of the test is 9-17 mm. and the primary spines are 2-2.3 times as 
much, as a rule. In one specimen, however, 11 mm. in diameter, 
the primaries are scarcely 15 mm. long. There is some diversity 
in the coloration of these individuals, for in some the brownish- 
red lines and markings in the interambulaca and on the abae- 
tinal system are quite distinct and in others they are nearly or 
quite wanting. The youngest primaries (i. e., those on the upper- 
most coronal plates) are normally quite different from the typ- 
ical spines of the midzone, lacking the longitudinal dentate 
ridges. Occasionally the difference is emphasized by color; in 



106 IOWA STUDIES IN NATURAL HISTORY 

one of the present series, these young spines are distinctly pink 
and unhanded. Fully developed primaries are more than twice 
the test-diameter, nearly cylindrical or terete, with the distinct, 
dentate, longitudinal ridges equally developed on all sides. In 
specimens less than half grown they are often conspicuously 
banded with 5-8 ill-defined reddish-brown zones. 

The specimens in the present collection were taken at the fol- 
lowing stations off the southwestern coast of Barbados. 

Station 9. May 16, 1918. W. by N. Pelican Island, 2y 2 miles, 

100 fms. Rocky bottom. Tangles. 2 specimens. 
Station 34. May 23, 1918. S. E. of Hastings, 2 miles off shore, 

80-90 fms. Rocky bottom. Tangles. 1 specimen. 
Station 36. May 23, 1918. S. W. of Carlisle Bay, 2 miles off 
shore, 80-90 fms. Rocky bottom. Tangles. 1 specimen. 
Station 46. May 25, 1918. N. N. W. Pelican Island, due west 
of Prospect, 2 miles off shore, 100 fms. Tangles. Bottom 
not recorded. 1 specimen. 

TRETOCIDABIS BARTLETTI 

Dorocidaris bartletti A. Agassiz, 1880. Bull. M. C. Z., 8, p. 69. 
Tretocidaris bartletti Mortensen, 1903. Ingolf Ech., p. 16. 1910, 

Bull. 74 U. S. Nat. Mus., pis. 2 and 3. 

As with the preceding cidarid, all of the half-dozen individuals 
of this fine species are young, not nearly half grown, the test 
diameter ranging from 10 to 17 mm., with the primary spines 
15-27 mm. The color is commonly brighter than in affinis, the 
reddish tints being usually quite red and the test and small 
spines being often quite greenish. The bands on the spines are 
generally distinct and their number may be 8 or 9, although the 
spines are shorter than in affinis. The two species seem to occur 
together and the young are easily confused. But aside from any 
matters of coloration, the form of the primary spines is sufficient 
for separating the two species, even if the very different glob- 
iferous pedicellariae cannot be found. In bartletti, the typical 
primaries are flattened and the lateral dentate ridges are more 
conspicuous, with bigger dentations, than those of either dorsal 
or lower surface. This makes a noticeable contrast to the cylin- 
drical, uniformly ridged and generally longer spines of affinis. 



BARBADOS-ANTIGUA REPORTS 107 

Barbados is the type-locality for bartletti and all of the speci- 
mens at hand came from there. At two of the following stations 
Stylocidaris was also taken. 

Station 7. May 16, 1918. W. by N. Pelican Island, 2 miles, 80 
fms. Rocky bottom. Tangles. 1 specimen. 

Station 34. May 23, 1918. S. E. of Hastings, 2 miles off shore, 
80-90 fms. Rocky bottom. Tangles. 1 specimen. 

Station 35. May 23, 1918. S. W. of Needham Point, 2y 2 
miles off shore, 80-90 fms. Rocky bottom. Tangles. 1 
specimen. 

Station 36. May 23, 1918. S. W. of Carlisle Bay, 2 miles off 
shore, 80-90 fms. Rocky bottom. Tangles. 1 specimen. 

Station 37. May 23, 1918. Off Pelican Island, 2% miles, 100 
fms. Rocky bottom. Tangles. 1 specimen. 

Station 44. May 25, 1918. N. W. Pelican Island and S. W. 
Lazaretto, 2y 2 miles off shore, 90-100 fms. Medium coarse 
sand. Dredge. 1 specimen. 

CENTRECHINUS ANTILLARUM 

{Jidaris (Diadema) antillarum Philippi, 1845. Arch. Naturg., 
jhg. 11, 1, p. 355. 

Diadema setosum A. Agassiz, 1872. Rev. Ech., p. 274 (in part). 
Centrechinus antillarum H. L. Clark, 1918. Bull. Lab. Nat. Hist. 
Iowa, 7, No. 5, p. 24. 

Only a single small specimen of this most characteristic West 
Indian sea-urchin is in the present collection. It has the test 
about 30 mm. in diameter while the primary spines are some 55 
mm. in length. They still show traces of the youthful banding, 
so striking a feature of much smaller specimens, but the general 
impression of this specimen is unicolor, though it is by no means 
really black. 

In the "Narrative", Professor Nutting says this "black nui- 
sance" is found "almost everywhere in shallow water, both on 
sandy and rocky bottom", about Barbados, while it is also 
"abundant" at Antigua. Apparently it is abundant wherever 
it occurs, for it is very common at the Tortugas and along the 



108 IOWA STUDIES IN NATURAL HISTORY 

southern Florida coast, while at the other extreme of the West 
Indian region, on Buccoo Reef, Tobago, it is more abundant than 
at any other place where I have personally seen it. 



CENTROSTEPHANUS RUBICINGULUS* Sp. nOV. 

Plate I, figs 1 and 2. 

Test 12 mm. in horizontal diameter, 5 mm. high, decidedly 
flattened both above and below. Coronal plates 8 or 9 in each 
column, with no essential difference between ambulacra and 
interambulacra in this particular, but the interambulacra are 
about 4 mm. wide at ambitus while the ambulacra are scarcely 
3.5. Abactinal system large, 5 mm. in diameter, covered with 
a fairly thick skin; all the oculars are insert; genital plates 
large, each with a long genital papilla, the length of which about 
equals the width of the plate; periproct about 2.3 mm. across, 
covered with small roundish plates, set in thick skin. Uppermost 
abactinal primary spines, usually two of each vertical series, 
very small (1 mm. long, more or less), smooth and club-shaped; 
all the other primaries, especially those of midzone which are the 
longest (12-14 mm.), very rough with the usual rings of minute 
spinelets. Peristome 7 mm. in diameter, quite closely covered 
with non-ambulaeral plates among which the five pairs of buccal 
plates are easily distinguished by their larger size and their 
clusters of pedicellariae and the spinelets so characteristic of 
Centrostephanus. 

Pedicellariae of only two kinds so far as observed, ophiceph- 
alous and globiferous. The former have valves .25-.40 mm. 
long, with the loops 10-30 per cent more. These pedicellariae 
occur on the buccal plates and scattered about sparsely on the 
test ; those on the test are considerably larger than those on the 
peristome. The globiferous pedicellariae, as in the other mem- 
bers of the genus, have the valves imbedded in heavily pigmented 
glands; these pedicellariae therefore, though very small, are 
made conspicuous by their black tips ; the valves are .22-32 mm. 
long and terminate in 4 short, subequal, somewhat spreading 



1 Rubus =r red -j- cingulus — a zone or band, in reference to the banded spines. 



BARBADOS-ANTIGUA REPORTS 109 

teeth; the general form of the valves is very similar to that 
found in C. rodgersii (See Mortensen, 1904. Siam Ech., pi. IV, 
fig. 19) except that in the Australian species there are six ter- 
minal teeth. 

Peristome nearly white, but thick skin near mouth, tube-feet 
and gills yellowish. Pedicellariae pale reddish-yellow. From 
below ambitus upward the epidermis becomes thicker and stead- 
ily more and more pigmented until on the periproct it is quite 
black, especially at center. Primary spines whitish or glassy 
with 2-5 ill-defined but very distinct bands of red ; the shade of 
red is between nopal-red and garnet-brown of Ridgway's pi. 1 
(Color Standards and Nomenclature, 1912), and is quite free 
from any violet or purple tinge. The little club-shaped prima- 
ries on the abactinal plates have their distal halves bright rose- 
purple in striking contrast to their surroundings; the shade is 
very near the rhodamine purple of Ridgway's pi. XII. 

Holotype from Station 101. June 13, 1918. On Shoal Bank, 
about 3 miles W. of Needham Point, 25-40 fms. Sponge bottom. 
Dredge. 

It is a great pity that only a single specimen of this pretty 
little urchin was taken, for the genus, although occurring on the 
western coast of Mexico and also in the Mediterranean, has never 
been found hitherto in the West Indian region. Moreover it is 
probable that this is a very young specimen and it would be 
interesting to know to how large a size the species grows. The 
Australian species, rodgersii, is the largest, reaching a diameter 
of 100 mm., while the Mediterranean and Mexican species attain 
less than half that size, so far as we yet know. Neither species is 
at all well known. In every way, the West Indian species is 
nearest to that of the Mexican coast (coronatus) but it differs in 
several minor particulars. The coloration is noticeably different 
for in coronatus, the red which bands the spines is distinctly 
purplish and there is no trace of purple on the primaries of 
rubicingulus. More important is the difference in the globif erous 
pedicellariae ; in coronatus, the narrow part of the blade is short 
and the terminal teeth are very long (see A. Agassiz and H. L. 
Clark, 1908, Mem. M. C. Z., 34, pi. 51, figs. 18, 19) while in 
rubicingulus, the narrow part of the blade is longer and the 
teeth are very much shorter. Of course, more material is needed 



110 IOWA STUDIES IN NATURAL HISTORY 

before all the differences between the two species can be clearly 
set forth. 

COELOPLEURUS FLORIDANUS 

A. Agassiz, 1872. Rev. Ech., p. 102. 1883, " Blake' ' Ech., pi. 
VII. 

The specimens of this fine sea-urchin are all from the deeper 
water off southwestern Barbados. All are very young, the tests 
measuring only 6-13 mm. in horizontal diameter. The spines 
are generally more or less badly broken but when these are intact 
they are usually 4-4.5 times the test diameter. The only diver- 
sity these individuals show is in the degree of brightness of their 
coloration. Some have no trace of blue or lavender abactinally 
while others, larger ones, have it quite well marked. The 7 speci- 
mens were taken at the following stations : 

Station 7. May 16, 1918. W. by N. Pelican Island, 2 miles, 
80 fms. Rocky bottom. Tangles. 1 specimen. 

Station 19. May 18, 1918. iy 2 miles west of Needham Point, 
80 fms. Rocky bottom. Dredge. 1 specimen. 

Station 26. May 20, 1918. Due W. of Pelican Island, 75 fms. 
Rough, stony bottom. Dredge. 1 specimen. 

Station 34. May 23, 1918. S. E. of Hastings, 2 miles off 
shore, 80-90 fms. Rocky bottom. Tangles. 1 specimen. 

Station 36. May 23, 1918. S. W. of Carlisle Bay, 2 miles off 
shore, 80-90 fms. Rocky bottom. Tangles. 2 specimens. 

Station 88. June 7, 1918. Lazaretto E. by N. y 2 N., Pelican 
Island S. E. Depth (?). Fine sandy bottom. Dredge. 
1 specimen. 

LYTECHINUS CALLIPEPLUS 

H. L. Clark, 1912. Mem. M. C. Z., 34, p. 251 ; pi. 96, figs. 4-6. 
The rediscovery of this interesting little species by Professor 
Nutting's party is of real importance and the five specimens ob- 
tained throw a great deal of light on the specific characters, for 
the holotype was only 8.5 mm. in diameter and the largest known 
specimen was only 11.5 mm., while the largest in the present 
series is 20 mm. and another is 17. These larger specimens show 



BARBADOS-ANTIGUA REPORTS 111 

that the coloration is more striking and more distinctive than 
was suggested by the types. Each of the five specimens deserves 
separate consideration. 

The smallest is only 7 mm. in diameter and 4 mm. high. The 
whole abactinal surface is more or less reddish with indefinite 
and inconspicuous blotches in the ambulacra and interambulacra. 
The periproct, the proximal part of the oculo-genital ring and a 
large blotch at upper end of each interambulacrum are greenish- 
white. The abactinal spines are nearly all coral-red, but some 
have whitish tips. 

The next specimen is 9 mm. by 5, and has a somewhat different 
coloration, very similar to that of a third specimen, 11 mm. by 
6.75. In these individuals, the general color abactinally is green- 
ish-white but this is largely obliterated by the development of 
the red blotches in both the ambulacra and interambulacra. 
These blotches are more or less coalesced so that the median two- 
thirds of each interambulacrum and about half of each ambu- 
lacrum are quite reddish. The larger spines are greenish with 
red only at the base but the small spines are often tinged with 
red throughout. 

The specimen 17 mm. in diameter is 10 mm. high and its 
coloration is much like that of the largest specimen but it is 
somewhat greener, the red shades are paler, the markings are 
less distinct and all the spines, even the actinal, have a reddish 
tinge. 

The superb specimen from station 35 is 20 mm. in diameter 
and 12 mm. high ; the abactinal system is not quite 6 mm. across 
but the heavily plated peristome is 9 ; the primary spines are 4-5 
mm. long. There are 14 interambulacral and 15 ambulacral 
plates in each column. Ocular I is broadly insert but the other 
oculars are completely excluded from contact with the periproct. 
The test is greenish-white, nearly white abactinally, with large, 
squarish but irregular blotches of orange-brown or rusty-red at 
and above the ambitus. The shade varies according to moisture; 
it is brightest when wet. There are typically three blotches in 
each interambulacrum but the one at ambitus is low and im- 
perfect. There are four in each ambulacrum but the one at 
ambitus is rather faint. In both series, the next to the lowest is 
largest and brightest. The periproctal plates are nearly white 



112 IOWA STUDIES IN NATURAL HISTORY 

but the plates of the oeulo-genital ring are variegated with 
greenish and reddish tints. Most of the abaetinal tubercles are 
pale red. The actinal spines are nearly white but the bases of 
the larger ones and more or less of the entire length of small 
ones have a more or less marked greenish tinge. At and above 
the ambitus some of the spines become more or less pale red, 
the color being confined to the base of the spine or extending its 
whole length. The pedicellariae are white, as are the plates 
which cover the peristome. 

The additional data which these Barbadian specimens furnish 
show that callipeplus is a very well marked species quite distinct 
from any other member of the genus. In its coloration, it is 
more like pictus and anamesus of the western coast of Mexico, or 
verruculatas of the Indo-Paeific region, than it is like its West 
Indian congeners but the shade of red shown by the tubercles, 
spines and abaetinal spots is entirely different from anything 
exhibited by the other spotted species. 

Station 7. May 16, 1918. W. by N. Pelican Island, 2 miles, 
80 fms. Rocky bottom. Tangles. 1 specimen. 

Station 11. May 17, 1918. V/^ miles due west from white 
lighthouse at Needham Point, in line with red house, 67- 
70 fms. Stony bottom. Dredge. 1 specimen. 

Station 35. May 23, 1918. S. W. of Needham Point, 2y 2 
miles off shore, 80-90 fms. Rocky bottom. Tangles. 1 
specimen. 

Station 36. May 23, 1918. S. W. of Carlisle Bay, 2 miles off 
shore, 80-90 fms. Rocky bottom. Tangles. 2 specimens. 

LYTECHINUS EUERCES 

H. L. Clark, 1912. Mem. M. C. Z., 34, p. 247; pi. 107, figs. 4-6. 

This typically West Indian sea-urchin is represented in the 
present collection by only a single specimen. It is 11 mm. in 
diameter, with the abaetinal system Sy 2 mm. across, and ocular I 
nearly or quite insert. A few of the actinal spines show traces 
of red. The periproctal plates are light apple-green, but else- 
where both test and spines are white or whitish. 



BARBADOS-ANTIGUA REPORTS 113 

Station 6. May 15, 1918. North of Insane Asylum off spring 
garden or freshwater bathing place, 100 fms. Rough 
bottom. 1 specimen. 

LYTECHINUS VARIEGATUS 

Cidaris variegata Leske, 1778. Add. ad Klein, p. 85. 
Lytechinus variegatus A. Agassiz, 1863. Bull. M. C. Z., 1, p. 24. 
Toxopneustes variegatus A. Agassiz, 1872. Rev. Ech., pt. 1, p. 
298; pi. IVa, figs. 5, 6. 

In the Narrative of the expedition, Professor Nutting refers to 
the occurrence of this well-known species at several places in 
Antigua but does not speak of finding it at Barbados. Yet the 
only two specimens in the collection bear the label "Barbados". 
They are of about equal size (78 mm. in diameter with primary 
spines 13-15 mm. long) but differ strikingly in color and were 
evidently selected as examples of the extremes in coloration. 
One has the test pale brownish-white with only traces of green ; 
the tubef eet are very pale brown ; the pedicellariae, muscles and 
small spines are whitish; the peristome, heavily plated, is pale 
brownish with traces of green ; the primary spines are light 
green, whitish at base, dark at tip ; many have one or two faint 
dusky bands close to the tip ; of many, the tips are regenerating. 
The other specimen has the test dull light green and whitish; 
the tubef eet are pale brown ; the pedicellariae, muscles and mili- 
ary spines are white or whitish ; the heavily plated peristome is 
dull greenish ; the primary spines are deep, dark green, the tips 
becoming purplish but not markedly so; the secondary spines 
are pale yellow-green. In the Narrative (p. 189), Professor 
Nutting makes the interesting suggestion that the habit which 
both this species and Tripneustes esculentus have, of holding 
bits of sea-weed and other rubbish all over the dorsal surface, 
may be for the purpose of protection from the sun. It would be 
easy to ascertain whether this is the case and the habits of these 
sea-urchins would well repay careful investigation. 

TRIPNEUSTES ESCULENTUS 

Cidaris esculenta Leske, 1778. Add. ad Klein, p. XVII. 
Hippono'e esculenta A. Agassiz, 1872. Rev. Ech., pt. 1, pp. 135, 
301; pi. Via, figs. 1-3. 



114 IOWA STUDIES IN NATURAL HISTORY 

Tripneustes esculentus Bell, 1879. Proc. Zool. Soc. London, 
p. 657. 

In the Narrative, Professor Nutting refers often to this well- 
known "sea-egg", one of the very few sea-urchins which have 
any economic importance. In some cases, the sea-egg is called 
Hipponoe and in others, the correct name Tripneustes is used. 
Complaint is made (p. 188) that I have given no clue to the 
reason for abandoning Hipponoe, but this is hardly fair since I 
have given the full reference to Bell's paper where the matter 
was amply elucidated over forty years ago. It is no innovation 
of mine, to make use of Tripneustes. Hipponoe is preoccupied 
and there is no good reason for persisting in its use. 

Professor Nutting calls attention (pp. 80, 188) to two inter- 
esting color forms of the sea-egg, and both are represented 
among the eight specimens in the present collection. The two 
forms seem to be reasonably distinct and further investigation of 
their differences and the causes thereof is worth while. Ap- 
parently in the pallid form the development of pigment is inhib- 
ited, only a little on the triphyllous pedicellariae being visible, 
while the peristome and gills are brown. In the melanistic form, 
pigment is markedly developed, especially on the peristome (par- 
ticularly, close to the teeth), in the pedicellariae, in the tube-feet 
(except the white tips), in the tips of the branches of the gills 
and even to some extent in the epidermis of the test. The devel- 
opment of the pigment is not correlated with size but whether it 
is correlated with age is as yet unknown. 

The specimens at hand range from 34 mm. in diameter to 132 
mm. The primary spines on the smallest specimen are notably 
long (9 mm.), more than one-fourth the test-diameter. As a 
rule, they are hardly half as much as that. 

Of the eight specimens, seven are from Barbados and one is 
from English Harbour, Antigua. 

GENOCIDARIS MACULATA 

A. Agassiz, 1869. Bull. M. C. Z., 1, p. 262. 1872, Rev. Ech., pi. 
VIII, figs. 1-18 (as Temnechinus maculatus). 

Two bare, dead tests, without buccal membrane or periproctal 
plates, are the only representatives of this little sea-urchin in the 



BARBADOS-ANTIGUA REPORTS 115 

collection. Both the "Hassler" and the " Blake' ' took Geno- 
cidaris off Barbados, but in each case three specimens taken to- 
gether was the total capture, so it is obviously not common in 
that region. One of the bare tests of the present collection is 7 
mm. in diameter but the other is only 3.5. 

Station 84. June 6, 1918. Spring Garden bears E. N. E., 
Needham Point Light, S. E. Off shore V/ 2 miles, 100 
fms. Fine, sandy bottom. Dredge. 2 specimens. 

PSEUDOBOLETIA OCCIDENTALS, Sp. nOV. 

Plate II, figs. 1 and 2 

Test 54 mm. in diameter, 27 mm. high, only a little concave 
orally and rather flat abactinally. Coronal plates 25 in each 
interambulacral column and 30 in the ambulacra; the inter- 
ambulacra are about 19 mm. wide at ambitus and the ambulacra 
about 14. Each interambulacral plate in the midzone has 4 
large primary tubercles, the outermost is slightly the largest, the 
innermost is smallest; a large secondary tubercle occupies the 
outer end of the plate, encroaching on the ambulacra ; there are 
8-10 much smaller secondary tubercles, chiefly along upper mar- 
gin of plate, and about a dozen irregularly scattered miliaries; 
orally the number of primary tubercles becomes reduced to 3 
and then to 2 and on the lowest plate to one ; the gill slits are 
very deep, reaching up between the tubercles of the third plate 
(from the peristome) ; aborally there are 4 primaries to the 
tenth plate (from the genital), 3 to the seventh' and 2 to the 
fourth or fifth. Each ambulacral plate in the midzone has 2 
primary tubercles and a secondary tubercle at each end; the 
outer secondary encroaches much on the poriferous area; it is 
wanting only on the lowest two plates and on the uppermost 
three or four; the inner secondary occurs only in the midzone; 
the inner primary occurs first on about the twelfth plate from 
the ocular. Pore-pairs in strongly curved arcs of four, the low- 
est distinctly nearer the ambulacral mid-line than the upper- 
most. 

Abactinal system small, only 9 mm. across, the periproct only 
4 mm. ; oculars I and V broadly insert, the others not nearly so j 



116 IOWA STUDIES IN NATURAL HISTORY 

genital pores large near outer end of plate; ocular pores very 
small, about half way between center and distal margin ; genital 
plates each with a large secondary tubercle, 3-6 large miliaries, 
and half a dozen or more minute miliaries; oculars with 3-6 
large, and a number of minute miliaries. Periproet covered with 
about 20 plates, among which the suranal is scarcely distinguish- 
able ; the larger plates each carry 1-3 large miliaries. 

Peristome large, about 22 mm. across, with deep gill-slits ; it is 
well plated but not heavily so ; buccal plates large, nearly circu- 
lar, the two of a pair close together, the pairs separated from 
each other by about a millimeter. Bach buccal plate carries 
about half a dozen slightly club-shaped miliary spines, besides 
numerous small stout tridentate pedicellariae. Most of the non- 
ambulacral plates of the peristome carry one or more miliary 
spines besides small stout tridentate pedicellariae. 

Primary spines about 12 mm. long at ambitus, terete basally 
and becoming flattened only slightly near tip; the tip itself is 
concave, not pointed; each spine has 20-22 well marked stria- 
tions. Secondary and miliary spines, slender, cylindrical, bluntly 
pointed. 

Pedicellariae numerous and diversified but only the small stout 
tridentate are at all common. In size and form the pedicellariae 
offer no characters by which they can certainly be distinguished 
from those of P. macidata. Olobiferous pedicellariae rare, of 
two sizes, one with valves about .80 mm. in length, the other 
with valves about half as large. Ophicephalous pedicellariae 
rare, with valves about .50 mm. long and loops .15 mm. more. 
Tridentate pedicellariae in at least three forms: (a) slender, 
with valves, 1.25 mm. long; (b) small stout, with valves about 
.50 mm. long; and (c) big, stout, with valves over a millimeter 
long, half a millimeter wide and very serrate margins ; only one 
of these big pedicellariae was noted. Triphyllous pedicellariae 
with valves .22 mm. long and about .18 mm. wide near tip. 

Color (in alcohol) pale brown with a distinctly greenish cast, 
the midzone with about 20 large irregular blotches of a dis- 
tinctly darker shade; there are two of these blotches in each 
ambulacrum and interambulacrum but they vary in size and 
distinctness. Primary spines pale fawn-color, decidedly greenish 
basally and very faintly pinkish at tips; on the dark blotches 



BARBADOS-ANTIGUA REPORTS 117 

the primaries are deep brownish-green, light only at the tips, but 
there is much diversity in the relative proportions of green and 
pale fawn-color. 

Holotype labelled only "Barbados", but Professor Nutting 
tells me that "in all probability it came from a depth of be- 
tween 30 and 100 fms." 

The discovery of Pseudoboletia in the West Indian region is 
certainly one of the most noteworthy results of the Barbados- 
Antigua Expedition, for the genus is not known on the western 
coast of tropical America and is really characteristic of the 
Indo-Paciflc fauna. On June 10, 1904, the " Scotia' ' took two 
specimens of a Pseudoboletia in 40 fms. off the island of Ascen- 
sion, in mid- Atlantic but well south of the equator. It is re- 
markable that the new species from Barbados is not very close to 
this Atlantic species, 1 which has five pairs of pores to an arc and 
banded actinal spines, but is so very close to P. maeulata of the 
Philippines that one hesitates to call them distinct. The follow- 
ing differences however warrant keeping them separate, at least 
until more material is available. In maeulata, the inner primary 
tubercle of the ambulacra appears first on the seventh, eighth or 
ninth plate from the ocular, in specimens 52-55 mm. in diameter, 
while in occidentalis it occurs first on the tenth-twelfth plate; 
this is not an important character and will probably prove in- 
constant and unreliable. In maeulata the periproct is covered by 
about 30 plates and the oculo-genital ring is more granulated, 
than in occidentalis. The primary spines of the midzone in 
maeulata are markedly flattened, with bluntly chisel-shaped tips 
(though with a terminal concavity), and are 14r-16 mm. long. 
Their color too, green at base and red-purple or reddish at tip, is 
quite different from the pale colors of occidentalis. 

In view of the insignificance of these differences, the question 
naturally arises whether the Barbados specimen was not acci- 
dentally brought from the East Indian region (or possibly from 
Hawaii). Professor Nutting assures me there is no doubt what- 
ever that the specimen at hand was collected at Barbados. It is 
not inconceivable that a small specimen of maeulata might have 
been brought on a very foul ship bottom through the Panama 



1 Kcehler called the specimens from Ascension P. maeulata but they really represent 
quite a different species, which I have proposed (1912, Mem. C. Z., 34, p. 344) to 
call atlantica. 



118 IOWA STUDIES IN NATURAL HISTORY 

Canal to Barbados, but that seems so highly improbable that we 
are better justified in believing that Pseudoboletia is a natural 
member of the Barbadian fauna. It is strange that neither the 
"Blake", the "Hassler", nor the "Albatross", nor any other 
collector in the West Indies, has met with the genus but the 
reason may be that the vessels mentioned did nearly all their 
collecting outside the 100 fms. line while the other collectors 
have done very little dredging at any depth. The teeming area 
between 10 and 100 fms. has scarcely been touched as yet. 

ECHINOMETRA LUCUNTER 

Echinus lucunter Linne, 1758. Sys. Nat. ed. 10, p. 665. 

Echinametra subangularis A. Agassiz, 1872. Rev. Ech., p. 283, 
pi. Xa, figs. 2-4. 

Echinometra lucunter Loven, 1887. Ech. Linnaeus, p. 157. 

Of this very common species, there are 94 specimens in the 
collection, of which 7 are bleached bare tests. Only three are 
from Barbados, the remaining 91 being from the Pillars of Her- 
cules and English Harbour, Antigua. The largest specimen is 
53 mm. long, 43 mm. wide and 28 mm. high, while the smallest is 
about 9X8X4.5. Some of the specimens from English Harbour 
are very dark-colored, a very dark purple-drab or a violet-black. 
They are also quite wide in proportion to the length and look 
as though the ambitus were a circle, but examination shows the 
width is always 1.5-3 mm. less than the length. The Barbados 
specimens are of two types of coloration: 2 are fawn-color be- 
coming purplish-red at spine tips, while the third is dark olive, 
the primaries with purple tips. 

At English Harbour, specimens taken from the rocks near the 
entrance show the effects of the heavy surf in which they spend 
so much of their lives. The primary spines are nearly all dis- 
torted or regenerating at the tip. In the Narrative (p. 189), 
Professor Nutting describes the conditions under which the 
Eehinometras flourish at Antigua. In speaking of their occur- 
rence at Barbados (p. 83) he says that E. viridis is a "very com- 
mon form" and that E. lucunter is "less common". As there 
are no specimens of viridis in the collection and both Barbados 



BARBADOS-ANTIGUA REPORTS 119 

and Antigua are well outside its known range, I think dark 
greenish specimens of lucunter have been mistaken for viridis. 

CLYPEASTER ROSACEUS 

Echinus rosaceus Linne, 1758. Syst. Nat. ed. 10, p. 665. 

Clypeaster rosaceus Lamarck, 1801. Syst. Anim. s. Vert., p. 349. 

Echinanthus rosaceus A. Agassiz, 1872. Rev. Bch., p. 311; pL 
Xld, figs. 1, 2. 

The only evidence of the occurrence of this well known species 
in the region visited by the Iowa party, is a group of fragments 
of a bare test about 80 mm. long, taken at English Harbour, 
Antigua. 

MELLITA SEXIESPERFORATA 

Echinodiscus sexiesperforata Leske, 1778. Add. ad Klein, p. 
135. 

Mellita sexiesperforata Meissner, 1904. Bronn's Thierreichs, 2 y 
abb. 3, buch 4, p. 1384. 

There are three fine specimens of this well-known "key-hole 
urchin" from Barbados. Their color in alcohol is bright yellow- 
brown. While one specimen is longer than wide, 78X76 mm., 
the other two are distinctly wider than long, 80X82 mm. and 
66X69 mm. The labels do not indicate just where or under 
what conditions these urchins were taken, and there is no men- 
tion of them in the " Narrative". 

ECHINOEUS CYCLOSTOMUS 

Leske, 1778. Add. ad Klein, p. 109. 

This well-known cosmopolitan echinoid has taken on new in- 
terest recently from the fact that it is now fairly well demon- 
strated that it is a Holectypoid, the genus Echinoneus and its 
near relative Micropetalon being the only living representatives 
of that order (See Hawkins, 1920, Phil. Trans. Roy. Soc. (B), 
209, p. 442). Both at Barbados and Antigua, Echinoneus was 
found in its customary habitat, in the sand beneath rock frag- 
ments. There are 3 specimens in the collection from Barbados: 



120 IOWA STUDIES IN NATURAL HISTORY 

and 33 (of which 18 are bleached, bare tests) from English Har- 
bour, Antigua. The smallest specimen is 7 mm. long by 5 mm. 
wide; the largest is 35X29 mm. The form of the test shows 
much diversity, the width ranging from .66 to .77 of the length 
and the height from .39 to .48. 

AGASSIZIA EXCENTRICA 

A. Agassiz, 1869. Bull. M. C. Z., 1, p. 276. 1883, Mem. M. C. Z., 
10, pi. XXV. 

Twice during the dredging off Barbados, the bare dead tests of 
this species were met with. All are small, ranging from 5.5 to 
9.5 mm. in length; the largest is 8.5 mm. wide and 8 mm. high. 

Station 48. May 27, 1918. S. W. of Lazaretto, W. by N. of 
Pelican Island, 25-72 fms. Coarse coral sand. Dredge. 
3 specimens. 

Station 77. June 3, 1918. Cable station bears Sy 2 S. 1 mile 
off shore. 40-50 fms. Dead bottom — coarse sand. 2 
specimens. 

BRISSUS BRISSUS 

Spatangus brissus (var. unicolor) Leske, 1778. Add. ad Klein, 
pp. xx, 182. 

Brissus brissus H. L. Clark, 1917. Mem. M. C. Z., 46, p. 218. 

This spatangoid, almost always found associated with Echino- 
neus, was not taken at Barbados, although it is recorded from 
that island and probably occurs there. From Antigua there are 
48 specimens, of which 4 are bare tests. One was taken at the 
Pillars of Hercules but all the others are from English Harbour. 
The smallest specimen is 22 mm. long, 17 mm. wide and 11 mm. 
high, while the largest is 61X45X36 mm. One specimen is 
peculiarly deformed, as a result of a serious injury at some time 
in interambulaerum 4, which is now entirely healed; this speci- 
men measures 42X35X25 mm. In the Narrative (pp. 190-192), 
Professor Nutting discusses in a very interesting way the pecu- 
liar subsurface habits of Brissus and Echinon'eus. My own ob- 
servations of these species agree well with those of the Iowa 



BARBADOS-ANTIGUA REPORTS 121 

party, but I have not noted that the depth below the surface was 
as great as six inches. In many cases the animals are just below 
the surface. As a rule the larger the animal the more deeply it 
is buried. Probably the animals move up and down in the sand 
with changes in temperature and tidal conditions, and no doubt 
the larger individuals move more rapidly and greater distances 
than the smaller ones. The food is certainly in large part di- 
atoms and other unicellular organisms. 

Museum of Comparative Zoology 

Cambridge, Mass. 

May 28, 1920 



PLATE 1 




Centrostephanus rubicingulus. X-3. 
1. Oral view. 2. Aboral view. 



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PLATE il 






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Pseudoboletia occidentalis. Nat. size 

1. Side view. 2. Aboral view. 






* > >? finable from the University 

i. :})!•;} ri.-m ; Price, $1.50 



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