Received in Exchange
from
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
i^
o +^
c „
= 3
___^ 1
Is
o
U o
fl
w^
Q e8
is
O «J
l53c=
1-3 ^
H^ivi
si
ftv*'*}l
si
m Pi
fflp '''**
2 P
^3 <u
^
iS-y
o
^i^'%'
«.s
^S tt i
03
-t-> to
(0
g o
ft
— o
-T* P<
WM
s -S
>
3^
jD
jflffiUH-";A
co co
wn-Til— ^
c~
m&MZi
-H
liRIp
J4 P!
CO CO
wSf
lfi-afti
o.S
'42 o
8^
£2-
^ 0) !fl
5 2 ^
1*1
CO «
CD P
§-M
?J C c
&8"3
8 fl ft
ft o ^
-S Q J>
4?o^
CO O CD
SrO bO
p cO'-O
U^JO
copq°
e <d^
•tig 8
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
■-»m;l#
p* ;■■;■": /,.,;.;,,,;.;;::■■
'" " ^- 'Z
.:■■■■»::;■%
■■'" ■■ - ' ■■■■■■ -.*■ 5 : ..;;i ■! .-
fie
'.'■(■i'f^lOSS'-
;;.:, . ■ ■
*;*-<# ■
,...■: t ;^% iA
Sppft*^ ;, >*< " "' -^» .*v** "^^^^^PP*WWwB^||HB^B^^B
H&&S&- J, $ &* '*± ** "ft "i ' * ' ■ . > L . :•'"
* ,»«*><+* * * ' * f *fr iViift»iMM|
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
6uicur
wqsunp u
uojfio(o|
&mqu»v»n<)\
J»A;y fi«i|ioi
fflB
g
I .9
3$ V
AS
4 i
'•tn wd
JZ£
a be
i* O bo
3 0)
1- w d
j! « «
o e
0> id
biJT-i
-a .2
c
a ft
li&
enA3 fl 3
05 K
3 2
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
**2
-S.SS
o 3J .
~*K
£ 0) .
.2 w £
12 !h
« 'cfi o
^1
oj +j <D
" o=r!
o-o?
,■, :tf:- J.'-:
§ s£
fto >>
Ǥ*
^hJ
>> o
^
cm a: a
.- S -~
cjj m &
£ £S
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.
,*h
PLATE il
tftSSfei^
^^^ L
^\sMji
:-:^Mf;W$M
Pseudoboletia occidentalis. Nat. size
1. Side view. 2. Aboral view.
* > >? finable from the University
i. :})!•;} ri.-m ; Price, $1.50
THE UNIVERSITY OF MICHIGAN
GRADUATE LIBRARY
DATE DUE
**■•;■■■ "
eiOUNfi
UNiv. „-. ..wH,
LIBRARY
UNtVERSI'
XV
7
' 1-,-v- ..
%
&*
ffySs
tew
DO NOT REMOVE
OR
MUTILATE CARD
Live Music Archive
Librivox Free Audio
Metropolitan Museum
Cleveland Museum of Art
Internet Arcade
Console Living Room
Books to Borrow
Open Library
TV News
Understanding 9/11