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Full text of "Report of the state entomologist on the noxious and beneficial insects of the state of Illinois"

LIBRARY OF 




IS85-IQ56 



EIGHTEENTH REPORT 



State Entomologist 



ON THE 



Noxious and Beneficial Insects 



State of Illinois 



SEVENTH REPORT OF S. A. FORBES 
For the Years 1891 and 1892 



Reprinted by authority of the State of Illinois. 



1920 



Springfield, III. 

Illinois State Journal Co., State Printers. 

19 2 



CONTENTS. 

PAGE. 

List of Descriptions V 

Letter of Transmittal VI 

General Record for 1891 and 1892 .VII 

Insect Injuries to Indian Corn. 1 1 

Introductory 3 

Classificaiion of Injuries 6 

Injuries to the Seed in the Earth 6 

Injuries by Ants 7 

Solenopsis debilts 8 

Myrmica scabrinodis lobicornis 9 

Injuries by Beetles 10 

Agonodertts pallipes 11 

Aphodius granarius 12 

Clivina impressifrons 13 

Injuries by Footless Maggots 14 

' Phorbia fttsciceps (The Seed-corn Maggot) 14 

Sciara sp. (The Black-headed Grass Maggot) 16 

Injuries by Six-legged Larvae 18 

Systena taniata (The Pale-striped Flea-beetle) 18 

Ipsfasciatus (The Banded Ips) 20 

Wireworms 24 

Synopsis of Genera 27 

Cardiophorus sp 28 

Drasterius elegans 29 

Agriotes mancus (The Wheat Wireworm) 32 

Agriotes pubescens ..: 34 

Melatiotus communis 34 

Melanotus jissilis 36. 

Melanotics infanstus 36 

Melanotus cribulosus (The Corn Wireworm) 37 

Asaphes decoloratus 39 

Natural Enemies 41 

Prevention and Remedy 42 

Injuries to the Roots 45 

Injuries by Plant Lice and Mealy Bugs 48 

Aphis maidiradicis (The Corn Root Aphis) 50 

Injury to Corn 51 

Injury to other Plants 52 

Life History 54 

Relation to Ants 57 

Relation to Corn Lt.af Aphis 60 

Natural Enemies 65 

Economic Procedure 65 

Description 70 

On the Ants Attendant on the Corn Root Aphis 72 

Schizoneura panicola (The Grass Root Louse) 75 

Life History 77 

Relations to Ants 79 

Description • 79 

Trama erigeronensis 82 

Description 82 

Forda occidentalis, n. sp 84 

Description 84 

Tychea brevicornis, n. sp 88 

Description 86 



PAGE. 

Geoica squamosa, n. gen. et sp • 87 

Description 89 

Rhizobius spicatus, n sp. (The- Woolly Grass Root Louse) 92 

Description 93 

Dactylopius sorghiellus (The Corn Mealy Bug) 94 

Description 95 

Injuries by White Grubs 96 

Lachnosterna and Cyclocephala (Common White Grubs) 96 

Injuries to Corn and other Vegetation 97 

Life History and Habits 102 

Lachnosterna, Imago 102 

The Egg 104 

Larval Period 105 

Pupation and Formation of Beetle 106 

Cyclocephala 107 

Natural Enemies 107 

Preventive and Remedial Measures 112 

Local Prevention 112 

General Prevention 113 

Remedial Measures 116 

The Contagious Diseases of the White Grubs 117 

Description of Grubs I ;• 121 

List of Illinois Species of Lachnosterna 122 

Key to the Illinois Species of Lachnosterna 123 

Allorhina nitida (The Green June Beetle) 127 

Prionus 128 

Injuries by Root Worms., 129 

Diabrotica 12-punctata (The Southern Corn Root Worm) 129 

Life History 131 

Natural Enemies 132 

Remedial Measures 134 

Description 134 

Diabrotica longicornis (The Northern Corn Root Worm) 135 

Injuries to Corn 136 

Food of the Beetle 138 

Life History 139 

Habits of Beetle and Larva 140 

Natural Enemies 142 

Prevention and Remedy 142 

Description I 43 

Explanation of Plates I* 6 



LIST OF DESCRIPTIONS. 



1. Solenopsis debilis, Mayr: worker, p. 9; female, p. 9; male, p. 9. 

2. Myrmica scabrinodis lobicotnis, Nyl.: worker, p. 10; female, p. 10; male, p. 10. 

3. Agonoderus pa/lipes, Fab., imago, p. 12. 

4. Aphodius granarius, Linn., imago, p. 13. 

5. Clivina impressifrons, Lee imago, p. 13. 

6. Phorbiafuscieeps, Zett. (The Seed-corn Maggot): larva, p. 15; puparium, p. 16; imago, p. 16. 

7. Sciara sp.: egg, p. IT, larva, p. IT: pup;!, p. 18; imago (female), p. 18. 

tna tmniata, Say (The Pale-striped Flea-beetle): larva, p. 19; pupa. p. 20; imago, p. 20. 
9. Ips fascia/us, Oliv. (The Banded Ips.): larva, p. 22: pupa. p. 23; imago, p. 24. 

10. Elaterida\ generic synopsis of larvse, p. 27. 

11. Melanotus, larval characters, p. 28. 

12. Cardiophorus sp.. larva, p. 28. 

13. Drasieriits elegans. Fab.: larva, p. 30; imago, p. 31. 

14. Agriotes mancus. Say (The Wheat Wireworm): larva, p. 33; pupa. p. 33; imago, p. 34. 

15. Melanotus communis, QryW.: larva, p. 35; imago, p 35. 

16. Melanotus fissilis. Say. imago, p. 36. 

17. Melanotus infaustus, Lee, imago, p. 36. 

18. Melanotus cribulosus, Lee. (The Corn Wireworm), larva, p. 38; imago, p. 39. 

19. Asaphes decoloratus. Say: larva, p. 40; imago, p. 41. 

20. Corn Root Lice, table of species, p. 50. 

21. Aphis maidiradicis , Forbes (The Corn Root Aphis): wingless viviparous female, p. 70; pupa 

of winged viviparous female, p. 71; winged viviparous female, p. 71; oviparous female, 
p. 71; 3gg, p. 71; male, p. 71. 

22. Lasius niger, Linn., and its variety alienus, Forst., worker, p. 74. 

23. Scliizoneura panicola, Thos. (The Grass Root Louse): wingless viviparous female, p. 79; 

pupa. p. 80; winged viviparous female, p. 81. 

24. Trama erigeronensis, Thos., wingless viviparous female, p. 83. 

25. Forda occidentahs, n. sp., wingless viviparous female, p. 84. 

26. Tychea brevicomis, n. sp., wingless viviparous female, p. 86. 

27. Geoica squamosa, n. gen et sp.: genus, p. 89; wingless viviparous female, p. 90: pupa, p. 91; 

winged viviparous female, p. 91; wingless oviparous lemale (?), p. 92; male (?), p. 92. 

28. Rhizobius spicatus, n. sp., (The Woolly Grass Root Louse), wingless viviparous female. 

p. 93. 

29. Dactylopius sorghiellus, Forbes (The Corn Mealy Bug): adult female, p. 95; egg, p. 95. 

30. Genus Cyclocephala, larva, p. 121. 

31. Cyclocephala immaculaia, Oliv., larva, p. 121. 

32. Genus Lachnosterna. larva, p. 121. 

33. Lachnosterna fusca, Froh., and inversa, Horn, larva?, p. 121. 

34. Lachnosterna hirticula , Knoch, and rugosa, Mels., larva?, p. 122. 

35. Lachnosterna gibbosa, Burm., larva, p. 122. 

36. Lachnosterna. key to Illinois species, p. 123. 

37. Allorhiua nitida, Linn. (The Green June Beetle), larva, p. 128. 

38. Bacillus ru/ans, a. sp., p. 133. 

39. Diabrotica 12-punctata, Oliv. (The Southern Corn Root Worm): egg, p. 134; larva, p. 134; 

pupa, p. 135; imago, p. 135. 

40. Diabrotica longicomis. Say (The Northern Corn Root Worm): larva, p. 143; pupa, p. 144; 

imago, p. 144; egg, p. 145. 



LETTER OF TRANSMITTAL. 



Office of State Entomologist, 

Champaign, III., Dec. 21, 1892. 
To His Excellency, Joseph W. Fifer, Governor of the State of Illinois. 

Sir: I have the honor to transmit herewith rny seventh report as 
State Entomologist of Illinois, — the eighteenth from this office, — apply- 
ing to the years 1891 and 1892. 

I have had for some time the intention to present in my ento- 
mological reports a complete monograph of all insect injuries to Indian 
corn, to contain, when completed, not only an abstract of all published 
knowledge on the subject, but likewise all our own unpublished observa- 
tions accumulated during the past ten years. Believing that I could 
at present do the agriculture of this State no other service approaching 
this in value, I have prepared, as the greater part of this report, a first 
instalment of this treatise, consisting of a discussion of all insects 
injuring the planted seed and the roots of Indian corn. 

Respectfully submitted. 

S. A. Forbes, State Entomologist. 



VII 



GENERAL RECORD FOR 1891 AND 1892. 



The economic entomology of the years 1891 and 1892 has presented 
in Illinois scarcely a single notable feature, all crops having been, on 
the whole, unusually free from insect injury, and no very serious danger 
threatening at any time. 

The most interesting item of our record was the attack on young 
corn made in May and June, 1891, throughout the greater part of the 
State, from extreme Northern Illinois to Bunker Hill, but especially in 
the central and southern counties, by a small black jumping flea-beetle, 
ChcBt&cnema puMcaria, previously wholly insignificant as a corn insect. 
From live to ten or more of these beetles might sometimes be found on a 
single blade of young corn not more than five or six inches high, and the 
damage done was often so great as to give a yellow look to the entire 
field, due to the deadening of the terminal part of the leaf beyond the 
spots affected by the microscopic gnawing of those beetles. The injury 
was magnified by the cold weather of the season, during which the corn 
made very little growth; and it practically vanished with the advent of 
good growing weather. 

The chinch bug, which in 1889 and 1890 had very nearly disap- 
peared as an important factor in the agriculture of this State, has begun 
during the two years just passed again to take the upward turn. 

The almost uniformly high temperature of the spring and summer 
of 1890 and 1891 in northern and in southern Central Illinois, combined 
with light rainfall, amounting in some counties to little less than con- 
tinuous drouth, favored its development unusually in these sections. 

South of Central Illinois, the region affected in 1891 was a belt 
of counties extending from about the line of the Ohio & Mississippi Bail- 
road northward to the latitude of Spring-field, and local injury seemed 
likely for some distance north of this. In the north, the infested district 
was a roughly . triangular area in the northeastern corner of the State, 
of which Stephenson county marks the western angle and Kankakee 
county the southern. The distribution of injury within these limits was, 
of course, extremely variable, as is shown by the following examples of 
field notes and correspondence for 1891 ; first for Southern Illinois, and 
then for the northern part of the State. 

Washington. — Nashville, July 8. "Very destructive to corn in places." 
Dec. 7. Bugs generally diffused in limited numbers. Ashley, Dec. 7. Bugs 
generally diffused. Injury to wheat slight; corn more hurt. 

Clinton. — Carh/le. April 8 and 9. Hibernating in rail fences, corn shocks, 
etc. Second year here. Corn and wheat suffered some in 1890. Dec. 11. 
A few bugs. No harm done. 

Marion. — Vernon, July 1. "Leaving wheat for corn. Threaten injury." 
Salem, Dec. 9. A few bugs in corn. Odin. Sept. 27. In large quantities 
in one field of corn. Dec. 10. Locally abundant. 

Bond. — Greenville, June 27. "Corn alive with them." Dec. 3. Reported 
present in limited numbers last season. Effects seen mostly on corn; 



VIII 

some wheat light weight. Xmithboro. July 10. "Destroying corn." Dec. 4. 
Report similar to that at Greenville. Chief injury to corn. 

Montgomery. — Litchfield. May 27. Found bugs in most wheat fields 
along the road for four miles south of town. Wheat damaged most on 
corn ground and in the vicinity of places where corn shocks had stood 
over winter. Eggs abundant; a few young bugs. June 2. Few eggs seen; 
young bugs very numerous. From ten to fifteen per cent, of wheat in 
vicinity where corn shocks stood is ruined. July IS. Chinch bugs very 
abundant in and near woodlands on gray soil. Scarce on black lands 
north of them. Several rows of corn killed in many fields adjoining small 
grains. Scattered traces of insect disease, but not sufficient to promise 
any important aid. Sept. 23. Bugs collected in corn fields. Every field 
entered contained bugs enough to excite apprehension for next year. 

Shelby. — Herriek. Aug. 24. Second brood of chinch bugs will seriously 
damage corn; many stalks completely covered. Shelbyville, Nov. 15. Bugs 
present in considerable numbers. Injuries mostly confined to corn. 

Christian. — Morrissonviil&, July 4. "Leaving wheat for corn. Threaten 
great damage." Taylorville, Nov. 17. General diffusion of bugs reported. 
Some wheat reduced to light weight; corn next wheat fields injured. 

Macon. — Blue Mound, May 25. Corn and wheat infested by chinch bugs. 
June 27. Bugs of all ages, mostly young, present. A quart can nearly 
full of them sent to the office. 

In addition to the above list, a general diffusion of chinch hugs was 
also reported, at this time, with little or no injury, from the counties of 
Brown, Champaign, Coles, Macon, Sangamon. Effingham, Macoupin, St. 
Clair, Jefferson, Wayne, Clark. Lawrence. Edwards, White. Hamilton, 
Eandolph, Pope, and Johnson. 

St. Clair, Washington, Clinton, and Montgomery counties reported 
the bugs as being present in small numbers in 1890 also. A noticeable 
feature of the injury to wheat in this part of the State is that it suffered 
greater damage in the immediate vicinity of corn shocks, where the 
shocks were permitted to remain over winter. 

In northern Illinois trips of investigation made later in 1891 
showed the bugs to have been destructive locally in some nine counties 
for two years, and in a few places for three. Spring wheat, rye, and 
barley have afforded them the most acceptable breeding places. Destruc- 
tion of these grains in areas varying from a fraction of an acre up to 
two, three, or more, acres was common all through the infested region; 
and spring wheat was frequently light in weight because of the attacks 
of the bugs. Oats were quite generally infested, but did not suffer so 
severely as the other small grains, only now and then a small area show- 
ing noticeable injury. Corn next to spring wheat, rye, or barley, suffered 
considerable damage, several rows next such fields often being almost 
wholly worthless. Fields at a distance from the small grains contained 
bugs in limited numbers scattered all through them, but were not com- 
monly damaged noticeably. The situation in these northern counties 
in the summer and fall of 1891 is shown more specifically in the fol- 
lowing brief abstracts of field notes and correspondence : 

McHexry. — Marengo. Oct. 15. Second year of appearance. Great dam- 
age to rye, oats, and corn; some rye and corn not harvested. Woodstock, 
Oct. 16. Abundant all over the county. Wheat, corn, and barley attacked; 
corn not much hurt. Damage greater than last year. 

Booxe. — Belvidere, Oct. 15. Bugs reported five miles from town, where 
rye was being plowed up because of them. 

Wixxebago. — Rockford, Oct. 17. Abundant all through this region. Rye 
not much harmed; barley severely attacked; wheat and corn attacked vari- 



ously. One crop of corn reported not worth gathering: another piece was 
half destroyed; and one field of seven acres of wheat yielded fifteen bushels 
gross. Pecatonit a, Oct. IS. The bugs are in corn nearly a mile from the 
nearest stubble. Twenty acres of corn two miles north of town quite 
spoiled by bugs coming out of rye. 

Stephenson. — Ridott, Oct. 19. Bugs passed from rye to corn, doin,^ no 
very marked damage to either. On bottom-land found bugs on corn with 
no stubble near. Lena, Oct. 20. Bugs generally present, but little com- 
plaint of injury. One farmer reports bugs in wheat, going thence into corn 
and damaging it seriously. Warren, Oct. 20. Traces of chinch bugs only. 

Kane. — Hampshire, Oct. 14. Chinch bugs appeared here two years ago; 
lasi year in greater numbers than the year before. This year, barley, 
wheat, and corn damaged. Wm. Warrington had three acres of wheat de- 
stroyed, and H. Gilkerson had fifteen acres of wheat injured and three 
acres of corn destroyed. A neighbor of his had three or four acres of spring 
Wheal and two or three acres of corn destroyed. 

Hi: Kaxb. — New Lebanon, June 2. "Abundant in wheat and barley." 
(ji noa Oct. 15. Chinch bugs reported in wheat, Hungarian, and corn. They 
are also found in the vicinity of Sycamore. Shatibona, Oct. 20. Chinch bugs 
common in corn. Somewhat injurious. 

Ooi.e. — Davis Junction, Oct. 14. Traces of bugs all along the road from 
here to Stillman's Valley. 8tillman x s Valley, Oct. 14. A few rows of corn 
next rye and spring wheat injured. Paine' s Point, Oct. 15. Bugs went from 
rye into corn; both damaged some. Barley injured also, one acre of corn 
destroyed, and seven acres badly damaged. Oregon, Oct. 15. Five acres of 
corn east of town reported destroyed. Chana, Oct. 15. Bugs generally 
diffused between here and Paine's Point. Two or three acres of corn de- 
stroyed by bugs coming from rye. Forreston. Oct. 15. Bugs were flying 
thickly about this time last year. Hibernated abundantly in woods. Rye, 
barley, spring wheat, and corn hurt about as badly last year as this. North 
of town ten acres of rye was so badly damaged as to be plowed up. Five 
acres of corn badly damaged; much rye, barley, and spring wheat cut before 
it ripened to save it from the bugs. Reports from Mt. Morris, Baileyville, 
and Roclielle show the bugs to be generally distributed over the county. 

Whiteside. — Sterling, Oct. 21. Chinch bugs few, no important damage. 

Warning of possible danger impending was widely distributed by 
me through the bulletins of the State Agricultural Experiment Station 
in February, 1892,* accompanied by a brief program of general defence. 
In the northern part of the State, the presence of insect diseases, 
especially of the one known as the "white fungus" of the chinch bug, was 
repeatedly noticed by us in the fall of 1891 and the spring of 1892, but 
only where local rains gave it an opportunity for development. In 
Southern Illinois, however, nothing of the kind was found. Singularly 
in accord with these observations, the chinch bug in Northern Illinois 
multiplied less rapidly in 1892 than in the southern part of the State, 
but from both sections numerous calls came to the office for assistance 
and advice, usually in the form of requests for infected material with 
which to start "the chinch bug disease." Although convinced by my 
previous observations of these diseases and by laboratory and field ex- 
periments, conducted by us but not yet reported, that there was under 
the circumstances existing, very little probability of a valuable outcome 
to these experiments, I did what I could to supply the spontaneous de- 
mand by making artificial cultures and sending out both spores and 
infected insects. Every such sending was, however, accompanied with a 

* The Chinch Bug in Illinois, 1S91-1S92. Bull. Agr. Exper. Station No. 19 
(Feb., 1892), p. 44. 



warning intended to prevent the recipient from taking the experiment 
too seriously, believing, as I did, that harm was likely to result from a 
dependence upon this still problematical method to the neglect of older 
and more laborious and costly precautions. 

Another extraordinary occurrence in a minor field was the appear- 
ance in extreme Northern Illinois of two forest caterpillars almost 
unknown to the economic entomology of the State, which occurred in 
the summer and fall of 1892 upon the oak and hickory in such numbers 
as to completely defoliate these trees over large areas. My attention 
was especially called to them by correspondents in Freeport, Bockford, 
and Argyle, and an assistant was sent from the office to investigate the 
outbreak. The caterpillars responsible for the injury were Edema albi- 
frons and Halesidota carycc. The same injury, due to the same insects, 
spread widely northward into Wisconsin, but was not heard of by us 
south of the latitude of Chicago. 

An interesting investigation of injuries to books and papers by 
white ants was made in the winter and spring of 1892, in response to 
a request from the State Department at Springfield. Several rooms in 
the basement of the State House were found infested; cases in which 
books and documents were stored were hollowed out by these ants; and 
in many instances considerable injury had been done to the contents of 
the cases. 

Matters of minor interest and importance were the appearance of 
small outbreaks of the army worm in Central Illinois ; the occurrence 
of the meal moth (Pyralis farinalis) in potatoes; the extraordinary 
abundance in Cook county, for two or three years, of the cecropia moth, 
the larva of which does some damage in nurseries by defoliating young 
apple trees; the excessive abundance during both years covered by this 
report of, an injurious grass insect, Crambus camwellvs, which did 
noticeable damage to lawns ; and the first report of the arrival in the 
State of the notorious horn-fly, which since its advent from Europe 
had been confined to eastern localities. 

The clover seed midge (Cecidomyia leguminicola) , was found 
abundant in 1891 and 1892 throughout the northern half of the State, 
from Ogle county to Champaign, and it is very probably still more 
widely distributed. 

Specimens of a large flea-beetle, Disonyclia pennsylvanica, sent 
me from Griggsville, in Pike county, with the information that they 
were injurious to apples, were confined under a bell jar with, cut pieces 
of apple, upon which they fed very freely. They were, however, proven 
by experiment to be entirely unable to bite through the skin of unin- 
jured fruit. In the numbers in which they were found at Griggsville, 
hibernating in the apple orchard under bark, and especially under bands 
used as traps for the codling moth, they might easily do considerable 
injury by gnawing and holloAving out specked apples upon the trees. 



A Monograph of 

Insect Injuries to Indian Corn 



PART I 



INTRODUCTORY. 

For the past teii years the economic entomology of the corn plant 
has been made a leading subject of investigation in this Stale by the 
official entomologist, and in the course of these original studies a large 
mass of published matter has been scanned ami summarized. The 
preseni report has been prepared in the hope (I) of finally bringing to 
bear on the practice of the corn farmer in- Illinois all the' entomological 
matter that ought to affect his procedure, and (2) of so massing and 
condensing the data from which practical and theoretical conclusions 
are to be drawn as to make it unnecessary for the investigating ento- 
mologist to cover the same ground again. 

To the first end I have prepared descriptions and classifications of 
insect injuries to corn which I venture to hope will be found intelligible 
and practically useful to the actual tiller of the soil as well as to the 
economic entomologist ; and secondly, I have incorporated with this, for 
the especial benefit of the entomologist, more detailed and thoroughgoing 
discussions of the insects themselves and of their life histories, habits, 
and injuries, together with descriptions of the species in all stages as yet 
recognized. This report is thus written from both the agricultural and 
the entomological standpoints. 

The corn insects now recognized as in some way and to some extent 
injurious to some part of the plant number 214 species, of which 18 are 
known to infest the seed. 27 the root and the subterranean part of the 
stalk, 76 the stalk above ground, 118 the leaf, 10 the blossom. — that 
is the tassel and the silk, — 42 the ear in the field, 2 the stacked fodder, 
and 24 the corn in store, either whole or ground. The greater part of 
this long list, which is doubtless by no means really complete, is com- 
posed of those whose injuries are now so slight or rare as to constitute 
a possible menace rather than to cause a serious loss; but the history of 
economic entomology, and even of the entomology of this one plant, 
teaches us that we can rarely tell in advance what to expect of any pos- 
sibly injurious species. In fact, some of the insect enemies of corn now 
most destructive were not many years ago almost unknown even to the 
entomologist — the northern corn root worm and the corn root aphis, for 
example. 

The principal insect species infesting this plant are the seed-corn 
maggot and the wireworms, attacking the seed ; these latter insects, the 
white grubs, the corn root worms, and the root aphis, affecting the roots ; 
the cutworms and root web-worms, the army worm, the stalk-borer, the 
corn worm, the bill bugs, the chinch bug, the corn flea-beetle, and the 
grasshoppers, injuring stalk and leaf ; the corn worm, the corn root 
worms, and the grasshoppers, eating the flower structures and the ear; 
and the meal-moth and the weevils devouring the kernel in the granary 
or the meal in the bin. Of these, by far the worst at present are the 
wireworms, the corn root worms, the white grubs, the root lice, the cut- 
worms, the chinch bug, the grasshoppers, and the army worm. 



These major injuries have naturally received here the greatest share 
of attention, but a discussion of the minor and insignificant injuries 
which at first blush seem to have little or no agricultural importance, 
will nevertheless be of practical utility as indicating the probabilities 
with reference to the amount of injury to be anticipated when these 
minor attacks are noticed. 

For convenience of treatment, the general subject of insect injuries 
to corn will be divided, in discussion, into those to the seed, the root, 
the stalk, the leaf, the blossom, the ear, and the stored grain, whole and 
ground. 

The most serious ordinary injuries to corn, those which the plant 
is least able to sustain, are injuries to the seed and root, particularly 
those occurring early in the year ; but they are, fortunately, those against 
which precautionary or preventive measures may be most readily taken, 
and with the best effect. 

GENERAL INDICATIONS OP INJURY. 

Before beginning a description of injuries to each part of the plant, 
a few practical hints may be given which will aid to a recognition of 
insect attack from the general aspect of the field or from the appearance 
of the entire plant. 

1. If corn largely fails to appear in due time after planting, the 
farmer need not content himself with a surmise that his seed was poor 
or that the weather has been unfavorable, but should examine the seed 
itself for evidence of the work of one of several insects {ivireworms, 
seed-corn maggots, grass maggots, etc.) attacking it in the earth. 

2. If the young plants make an unequal start, some hills appearing 
earlier and growing more thriftily than others at the very first, the 
roots should be searched for the corn root louse; and even those hills 
should be examined in which the corn has not yet come up, as this louse 
sometimes infests the sprouting plant before it appears above ground. 

3. The abundant occurrence of ants in the corn field, sinking 
their burrows among the stalks of the hill, is evidence of the presence 
of the corn root louse in their company. 

4. If the growth of the corn is arrested or retarded in patches 
throughout the field, the leaves turning first yellow and then red, it is 
likely that the roots are infested by the same root louse, to be discovered 
by carefully digging up the hill and picking or gently shaking off the 
earth to expose the roots at their origin. If no insect enemy is found, 
the difficulty is quite likely to be due to a fungus attach known as the 
root blight of corn, a discussion of which does not come within the 
scope of this article. [See page -16, b.] 

5. If single stalks or entire hills are killed or withered when a 
foot high or less, search should be made among the roots and on the 
stalk below the surface for the wireworms and the white grubs. 

6. If the corn falls readily in a windy storm and does not after- 
ward rise, and if it may be pulled out easily after the ear has begun 
to form, it is probable that the roots are infested by the corn root worms 
or that they have been eaten by white grubs. 

7. If the plant remains green too long, maturing slowly, and if 
the field contains many sterile stalks or soft, imperfect nubbins, it is 
likely that the common 'com root worm, in some of its stages, will be 



found in or among the roots if search be made before September 1. If 
large numbers of grass-green beetles one fifth of an inch in Length 
(about the size of a common red lady bug) are seen on the silks and 
tassels of the corn, or feeding upon the fallen pollen collected at the 
bases of the Leaves, 01 upon the blossoms of ragweed or other flowering 
plants in the Held, the crop has suffered from an attack of the com root 
worm, of which these beetles are the adult, and the ground should be 
planted to some other crop the following year. 

8. A deformed and unequal growth of the foliage, especially of 
that unfolding from the roll of leaves at the growing tip of the plant, 
with more or less irregular and ragged injury, when the corn is from 
one to two feet high, is often due to an attack by the first generation 
of the corn worm, the second generation of which burrows in the kernels 
of the ear of corn during late summer and early fall. 

9. On the other hand, the presence of elongate holes, placed side 
by side in an orderly manner, in short rows extending across the well- 
opened leaf, is commonly the mark of an injury done when the corn was 
smaller by the corn bill bugs, several species of which will be described 
when injuries to the leaf are under discussion. 

10. An irregular eating away of the leaves of young corn, and 
a similarly irregular gnawing of the stalk near the ground when the 
plant is less than a foot in height, should lead to an examination of the 
earth about the base of the hill. If fine particles and small lumps of 
earth are found more or less closely webbed together in a mass approxi- 
mating the size of a hickory nut, some one or more of the species of root 
web-worms are doubtless at work in the field. 

11. The cutting of the young corn at or below the surface of the 
ground is an. injury too well known as the work of the cutworms to 
require more than bare mention here. 

12. The appearance in the side of the stalk of a hole about the 
size of a straw, with a brown moist powder exuding, is evidence of the 
presence of the stalk-borer, an insect which often does a great and prac- 
tically irremediable damage to young corn in early spring, especially in 
low grounds, by burrowing the stalk, pushing more or less of its excre- 
ment out at the mouth of its burrow. 

13. A similar, equally evident burrowing of the ear, the excre- 
ment from which escapes by a hole through the green husks or becomes 
mixed through the silks at the tip of the ear, betrays the presence of the 
corn worm already mentioned under 8. 

14. The eating away of the blade of the leaf in late summer and 
autumn so as to make large irregular holes, which may multiply and 
increase in size until they finally leave only the stripped midrib and the 
bare stalk — the injury being commonly very much worst along the edges 
of the field — is commonly due to grasshoppers. 

15. In the corn crib or granary, the commonest serious mischief 
is the peppering of the kernel with little round holes, each the diameter 
of the head of a pin. the first suspicion of which will frequently be 
aroused by the appearance of fine particles of meal sifting down some- 
where within sight. The insect most likely to be responsible for this 
mischief is the grain mofli : but various weevil species may also be 
involved. 



INJURIES TO THE CORN PLANT AND ITS PRODUCTS. 

CLASSIFICATION OF IXJUEIES. 

A. Injuries to the seed in the earth. 

B. Injuries to the roots. 

C. Injuries to the stalk. 

D. Injuries to the leaves. 

E. Injuries to the tassel and the silk. 

F. Injuries to the ear in the field. 
(I. Injuries to dry fodder. 

H. Injuries to stored corn and meal. 



A. Injuries to the seed in the earth.* 

Seed corn in the earth may he destroyed by being devoured at once, 
kernel by kernel ; by being bored through from side to side ; by being 
penetrated at some point and hollowed out in a way to leave an empty 
shell; or by being eaten away gradually from without. It need hardly 
be said that injuries of the first class are unknown to entomology, birds 
and mammals being the only corn-field pests which are capable of them. 

A kernel which has been smoothly perforated by a cylindrical chan- 
nel has probably been visited by a wireworm — a slender, cylindrical or 
flatfish, smooth, brown or brownish white, six-legged larva, likely to be 
found still working on the seed, the roots, or the underground part of 
the stalk. 

One which shows a round or oval hole at the surface, with no exit, 
will probably be found to contain either the seed-corn maggot — a white, 
soft, worm-like larva, without legs or distinct head, blunt at one end 
and pointed at the other — or the black-headed grass maggot — also a 
small footless white worm, but distinguished by its shining black head. 

If the grain has been gnawed away from without, the injury will 
commonly have begun with the germ or the softer part of the kernel 
about it, and the insect responsible will frequently be found more or 
less completely imbedded in the cavity which it has excavated. It may, 
in this case, be either one of the wireworms, as already mentioned; a 
small red or yellowish ant ; or one of at least three species of small hard- 
shelled beetles. 

If the damage has been done by ants, mealy particles are likely 
to be strewn through the dirt, as these insects do not devour the sub- 
stance of the grain, but tear it to pieces merely to lick up the fluids it 
contains ; but injuries due to the various beetles referred to do not differ 
in a way to suggest the species responsible. 

* For Injuries to the Roots, see p. 45. 



SYNOPSIS OF INJURIES TO SEED IN THE EARTH, AND 
ORDER OF DISCUSSION. 

1. Injuries by ants (Myrmicidae), which hollow out the kernel, com- 

monly scattering the meal through the dirt. Page 7. 
Solerwypsis debilis. (Plate IP, Fig. 2.) Page 8. 
Myrmica scabrinodis lobicornis. (Plate I., and Plate II., Fig. 

1.) Page 9. 

2. Injuries by small beetles, which gnaw the kernel from without, 

commonly beginning at the germ. Page 10. 
Agonoderus pallip&s. (Plate II., Fig. 3.) Page 11. 
Aphodius (jranarius. (Plate II., Fig. 4.) Page 12. 
Clivina impressifrons. (Plate II., Fig. 5.) Page 13. 

3. Injuries by footless maggots, which bury themselves in the seed. 

Page 14. 
Phorbia fusciceps (Seed-corn Maggot). (Plate II., Fig. 6 and 7; 

and Plate III., Fig. 1 and 2.) Page 14. 
Sciara sp. (Black-headed Grass Maggot). (Plate III., Fig. 3-7.) 

Page 16. 

4. Injuries by six-legged larvae, which gnaw or bore through the kernel. 

Page '18. 
Si/s!r/),i ianiata (Pale-striped Flea-beetle). (Plate III., Fig. 8; 

'and Plate IV., Fig. 1 and 2.) Page 18. 
Ips fasciatus (The Banded Ips) . (Plate IV., Fig. 3-5.) Page 20. 
Wireworms: Pages 24, 41, 42. 

Cardiophorus sp. (Plate IV., Fig. 6.) Page 28. 

Drasterius elegans. (Plate V., Fig. 1-3.) Page 29. 

Agriotes mancus (The Wheat Wireworm). (Plate V., Fig. 
4-6.) Page 32. 

Agriotes pubescens. (Plate VI., Fig. 1.) Page 34. 

Melanotus communis. (Plate VI., Fig. 3-5.) Page 34. 

Melanotus fjssilis. (Plate VI., Fig. 2.) Page 36. 

Mclanoltvs infaustus. Page 36. 

Melanotus cribulosus (The Corn Wireworm). (Plate VI., Fig. 
6-8; and Plate VII., Fig. 1.) Page 37. 

Asaphes decoloratus. (Plate VII., Fig. 2-4.) Page 39. 

DETAILED DISCUSSION OF INJURIES TO THE SEED. 

1. Injuries by ants (Mi/rmicidec), which hollow out the kernel, com- 
monly scattering the meal through the dirt. 

Injuries to corn by ants are of two kinds ; one indirect but serious ; 
the other direct, but of little importance because quite rare. The former 
will be treated in connection with insects affecting the root, since it is 
by rearing, transporting, and fostering the root lice of corn that ants 
are most injurious ; and the latter is given here in its place as an injury 
to the seed in the earth. 

Occasionally in searching for the causes of the failure of corn to 

germinate, or to grow thriftily after making its appearance, a kernel 

may be found wholly or partly hollowed out, the mealy interior being 

not devoured, but scattered about in the earth, while the cuticle or outer 

— 2 E 



8 

shell of the seed remains but little disturbed. The agents of this small 
mischief will frequently be found still buried in the cavities they have 
excavated — most commonly ants of a minute pale yellow species, a little 
more than a sixteenth of an inch in length, and very similar in size and 
general appearance to the minute "red ant" which often infests the 
pantry. This injury to corn requires no treatment so far as is now 
known, and, indeed, admits of none; but consistently with the plan of 
this treatise, which is intended not only to summarize existing knowl- 
edge but still more to serve as a basis for future investigation, the two 
species thus far connected by us with this injury to corn are here briefly 
treated. 

Solenopsis d'ebilis, Mayr.* 

(Plate II., Fig. 2.) 

This ant is but little known, either to farmers or entomologists, 
having, in fact, not been discriminated as a species until 1886, in which 
year it was described by Mayr,f of Vienna, from specimens sent him 
from North America. His description, with the appended remarks, is 
the only definite mention of it which I have found in the literature of 
entomology, with the exception of my own reference (under the name 
of 8. fugax) to its injuries to strawberries and kernels of corn in the 
earth in the Thirteenth Report of the State Entomologist of Illinois, 
published, in 1884 (p. 112). It is, however, probable that a reference 
under the same name made in 1889 by Mr. F. M. Webster^ to injuries 
to corn by ants in Indiana should really be applied to this species. 

Mayr reports the species from the District of Columbia, New Jersey, 
and Virginia, under stones and in a stump under ground, and from 
Texas and New York. Winged males and females appear in July and 
August. 

It was first found by us June 1-12, 1883, at Normal, Illinois, 
abundant in many fields of corn, both new and old, and afterwards, May 
14-24, 1886, infesting seed corn in the fields at Champaign. In the 
corn field these ants were usually collected about the kernels in the 
earth, and frequently more or less hidden in little cavities excavated in 
the softened grain. May 19, 1887, they were very abundant in a field 
of corn on sod in Champaign county, eating out the planted kernels. In 
autumn the same species has been detected by us indulging a similar 
appetite, but in a way to do no harm. September 11-21, 1893, it was 
found feeding on and within kernels of corn at the tips of ears, which 
had evidently been injured previously by crickets and grasshoppers. The 
solid substance of the grain is not actually eaten by these ants, — a fact 
which I demonstrated by dissection of the ants — but it is simply gnawed 
away, doubtless for the sake of the sweetish and oily fluids of the softened 
kernels. If plants start from seeds thus injured, they are shorter than 
others adjacent, and have a stunted, weak appearance. 

This species has also been several times noticed by us in September 
in attendance upon the root louse of corn, Aphis maidiradicis, sharing 
with several other species of ants the cares and benefits of this associa- 
tion. It occurs more frequently, according to our observations, at this 

* [=S. molesta Say wherever used in this report.] 

f Die Formiciden der Vereinigteli Staaten von Nord-america in Verhandlungen 
der k. k. zool-botan. Gesellschaft in Wien, XXXVI (1886), p. 461. 
t "Insect Life," Vol. II., p. 257. 



season of the year, with the corn root lice infesting purslane than with 
those upon the corn itself. 

Description. — This species of ant. and also the one following, belong 
to the family Myrmicidse, in which there are two nodes or thickened 
joints in the peduncle of the abdomen instead of a single node or scale- 
like joint, as in the large family of FormicicUe. Solenopsis is readily 
distinguishable by its peculiar antenna}, terminating, except in the male, 
in an enlarged club consisting of but two joints, the outer greatly 
elongate. 

The worker, which is the commonest form, is very small, about 1.5 
to 1.8 mm. in length, yellow or brownish yellow, the margins of the 
abdominal segments paler. The antennae are ten-jointed, and between 
them arc two longitudinal carinse which end in front in two small teeth. 
The metathorax is not armed with spines behind. The second joint of 
the peduncle of the abdomen is distinctly broader than the node of the 
first, and also much broader in front than behind. 

The female is 4.2 to 4.8 mm. in length. General color reddish 
yellow, the mandibles, head, thorax above, and abdomen, excepting 
margins of segments, yellow-brown. Antenna? as in worker, but with 
eleven joints. Frontal carinse as in worker, ending in two teeth. Meta- 
thorax without spines behind. Second joint of abdominal peduncle 
somewhat broader than first, and twice as broad as long. Abdomen 
polished. Wings hyaline, with pale veins and stigma. 

The male is 3.5 to 3.6 mm. long, shining dark brown, head black- 
brown; mandibles, antennae, and legs yellow. The antennas have a 
short scape and no distinct club; third joint about one and a third times 
as long as thick. Metathorax entirely unarmed. Wings hyaline. 

Myrmica scabrinodis lolicornis, Kyi.* 

(Plate I.; and Plate II., Fig. 1.) 

On the strength of a single observation, made in 1887, I mention 
here a second species of ant as injurious to seed corn in the ground, 
more commonly known, however, to economic entomologists because 
of its association with injurious plant lice. This is one of the most 
abundant of our smaller species, occurring very commonly in the 
food of the smaller insectivorous birds. It may be at once distin- 
guished from our other very abundant ants by the fact that, like the 
other members of its family, the stem or peduncle of the abdomen has 
two distinct, rounded joints instead of one, and by the presence of two 
conspicuous stout spines or thorns projecting backward from the pos- 
terior upper part of the thorax, which is itself finely lined and grooved 
longitudinally. 

This species extends around the world in the northern hemisphere, 
and it is scattered in North America from ocean to ocean. Its habits 
in Europe, as reported by Dr. Auguste Forel,f are notably different from 
those of the same variety in Illinois. There it is subalpine in range, and 
breeds in July and August; while with us it is universally distributed, 
and the sexes appear in September and October. 

* Determined by Mr. Theodore Pergande, of the United States Department of 
Agriculture, from a large number of specimens collected in Illinois, 
f Les Fourmis de la Suisse. 



10 

In Champaign, 111., May 13, 1887, about a dozen workers of this 
ant were seen tearing off fragments from a kernel of sprouted corn just 
below the surface of the soil, disposing of them much as does the species 
mentioned above. Many other grains were found in different parts of 
the same field similarly injured, being sometimes, indeed, completely 
excavated. The abundance of this species and the obscurity of the in- 
jury suggest that it may do greater mischief than would appear from 
this statement. 

This species, like the preceding, feeds in fall upon kernels of corn 
at the tip of -the ear in the field, most frequently following injuries by 
other insects, but certainly sometimes hollowing out the grain without 
their aid. 

Its relations to the corn plant louse will be described in another 
article. * 

Description. — This is a rather large ant, the worker (Plate II., Fig. 
1) being about three sixteenths of an inch in length, reddish in color, 
tinted above with brownish, or even blackish, especially on the head and 
abdomen, the legs a little paler. The body is deeply ridged and grooved 
lengthwise, excepting the abdomen, which is smooth and polished. Long 
hairs are scattered sparsely over the body. The long first joint of the 
antenna is bent nearly at right angles near the base, and sharply pointed 
on the outer side of the angle. The club at the end of the antenna is 
formed of three large joints. The thighs are thick, and the spurs at the 
end of the tibiae have a row of slender teeth on each side. There are 
two spines projecting backwards from the thorax. The males (Plate 
I., Fig. 2) and females (Plate 1., Fig. 1) are winged, a little larger 
than the workers, and are similar in size and general appearance. The 
males are the darker and the more slender, especially as to the abdomen ; 
the ridges on the thorax are also smoother, and run in various, direc- 
tions; and the spines on the thorax are very short and thick. In the 
wings the large cell adjoining the stigma is invaded from the middle of 
its further side by the stump of a vein. 

The sexes were noticed swarming September 14, 1893, after a rain 
following upon a long period of drouth. September 21 a nest was found 
at the foot of a stalk of corn (on which were aerial corn lice attended by 
this ant), this nest containing eggs, larvae of several sizes, pupae, and 
worker ants, in a chamber about half an inch high and three quarters of 
an inch in horizontal diameter, placed no more than three and a half 
inches below the surface of the ground. 

2. Injuries by small beetles* which gnaw away the kernel from without, 
commonly beginning at the germ. 

Three common beetles have been detected by us and reported by 
others as engaged in a somewhat noticeable injury to seed corn in the 

* Beetles commonly have four wings, the front pair of which are usually hard, 
thick, and opaque, fitting more or less closely upon the hinder part of the hody 
above, and similar in appearance to the rest of the upper surface. Beneath these, 
and next to the body, may be found the membranous hind wings, generally entirely 
concealed except during flight. The segment bearing the hind legs is fixedly attached 
to the hind body, but by a movable articulation. They also have a biting mouth 
furnished with two pairs of jaws. 



11 

earth, two of thorn among the most abundant of our Illinois insects, and 
the third also common, but too small to be noticed frequently by the 
ordinary observer. 

Agonoderus pallipes, Fab. 

(Plate II., Fig. 3.) 

This oblong, pale brown beetle, with a blackish cloud on the back, 
is a species of common notoriety (although it has never received an 
English name) because of its annoying abundance at lights in early 
spring. Hibernating as an adult, it leaves its winter quarters with the 
first warm sunny days, and flies abroad at night in countless myriads. 
Shortly afterwards the eggs are laid in the earth, and a new generation 
comes forth abundantly in June and July. The adults themselves may 
be found, however, throughout the year. It is possible that more than 
One generation occurs in a season. We have noticed, in fact, a disagree- 
able abundance of these. beetles at lights on warm September evenings. 
The species ranges throughout all. or the greater part, of the United 
States and Canada. 

It was first made known to me as injurious to seed corn in the 
ground by a note from Mr. Thomas Huber, of Illinois City, Eock Is- 
land count)*, dated June 4, 1883, and accompanied by a specimen of the 
beetle "found in seed corn, buried in the kernel, eating the germ and 
part of the inside." In Bulletin No. 12 of the U. S. Department of 
Agriculture, Division of Entomology (p. 44), Professor Eiley reports 
the receipt of this beetle during the summer of 1885, with the informa- 
tion that it was injuring young corn by gnawing into the seed and by 
eating the sprouting roots. One of these observations was confirmed by 
the sending of a specimen together with an injured grain. The exact 
amount of damage was not stated, but it was said to be quite extensive. 
Even before these observations I had myself detected this beetle injur- 
ing the roots of corn to some small extent;* a point determined by the 
dissection of specimens taken in corn fields, among the roots. Nearly 
half the food of these dissected specimens, however, consisted of frag- 
ments of chinch bugs, ■ and other insect remains. The character and 
amount of this injury to corn have not heretofore been such as to call 
for protective treatment, but if the beetle should become sufficiently de- 
structive to make such measures profitable, it is likely that "a satisfactory 
remedy will be found in soaking all seed corn for a short time before 
planting in some arsenical solution, such as Paris green or London pur- 
ple, in water. Such a course will not injure the germinative quality 
of the seed, and will probably result in the death of all beetles which 
attempt to gnaw the seed/'f 

This species was described by Pabricius in 1792}, but its economic 
record did not begin till 1882, when, in treating of the food relations of 
predaceous beetles in my "Twelfth Eeport of the State Entomologist" 
(p. Ill), I discussed its food under the name of Agonoderus comma. In 
May, 1883, I also treated the food of the specie? in an article on the 
"Food Eelations of the Carabidae and Coccinellida?.'^ Professor Eiley, 

♦Twelfth Report State Entomologist of Illinois, p. 43. 

f Bulletin No. 12, U. S. Department of Agriculture, Division of Entomology, p. 45. 

t Ent. Syst. I., p. 159. 

§ Bull. 111. State Lab. Nat. Hist., Vol. I, No. 6 (1883), pp. 43, 50. 



12 

in Bulletin 12 of the U. S. Department of Agriculture, Division of En- 
tomology (1886, p. 41), records an injury to seed Corn by this beetle, 
and figures the beetle and a grain of injured corn. He had previously 
published the same observation in the ''Daily Gate City" of Keokuk, 
Iowa, for June 28, 1885, 

Description. — Length, 6-8 mm., about three times as long as wide, 
a little depressed. Color black, shining, extensively marked with brown- 
ish or reddish yellow; legs, palpi, and base of antennas pale brownish 
yellow. Head etnirely black, thorax and wing covers widely margined 
with brownish yellow, the wing covers also narrowly margined on the 
inner edge, and often in front. Disk of prothorax often more or less 
brownish yellow. Beneath black, the prothorax and tip of abdomen 
more or less brownish or yellowish. Mentum not toothed at middle, 
antennas with two basal joints smooth. Prothorax a little broader than 
long, much narrowed behind, hind angles rounded, adjacent impressions 
feeble and punctate. Wing covers with distinct scutellar strise, a sin- 
gle hair-bearing puncture on the inner edge of the third interval behind 
the middle. 

Apliodius granarius, Linn.* 

(Plate II., Fig. 4.) 

The fact that a common small shining black clung beetle, very 
abundant in stable manure, where it feeds in part on particles of undi- 
gested grain, may under favoring conditions transfer its attentions to 
seed corn in the hill, gives occasion for brief mention of this insect here. 

Our only knowledge of this injury comes from Professor C. H. Fer- 
nald of the Massachusetts Agricultural College^ who received speci- 
mens of this beetle from Lancaster, Massachusetts, with the statement 
that they had been found destroying seed corn in the ground before it 
sprouted. 

"This insect," he says, "has long been known in America, having 
found its way here many years ago from Europe, its native country. 
The different species of Aphodins, while in the larva state, feed in sta- 
ble manure, and if this be used as a fertilizer in the hills these insects 
will emerge at the very place where they can do great damage. They 
are also liable to attack the various kinds of seed grain which have been 
sown on lands where stable manure is used. In this case, however, the 
loss is not so noticeable, since the destruction of a few kernels of wheat 
usually provokes only the remark that It did not come up/ But when 
the manure infested with these beetles is put into hills, and a few 
kernels of seed only put into each. They may be able to destroy the whole 
crop. 

"It is recommended, when these beetles are troublesome, to soak 
the seed in water for a short time, and then after pouring off the water 

* Ajihoclins lutulentus is pometimes included in lists of corn insects on the 
strength of the following observation contained in the Report of the Entomologist of 
the U. S. Department of Agriculture for 1881 (p. 65) : 

"On January 8, J. G. Barlow, Cadet, Washington county, Missouri, sent speci- 
mens of Aphodius lutulentus which had been injuring grains of corn contained in 
cow-dung." 

This species may evidently infest corn in the hill under circumstances like those 
given above. 

f Bull. No. 1. Hatch Experiment Station, Mass. Agr. Coll., p. 3. 



to stir in with it a mixture composed of one pari of I 'a ris green to twenty 
parts of flour. The reason why we recommend Hour instead of plaster, 
or other substances, as a diluent, is that lour is attractive as food for 
the beetles, and they will eat the poisonous mixture more readily/' 

Description. — The beetle is from I mm. to 6 mm. in length, ob- 
long and very convex. Color deep shining black, beneath brownish, 
legs dark reddish brown. The head has three frontal tubercles, very dis- 
tinct in the male, less so in the female. Clypcus projecting over and 
concealing mouth pails, front margin broadly emarginate at middle, 
without angulation. Antennas nine-jointed, with a three-jointed club. 
Thorax convex, rather finely and sparsely punctured. Wing covers with 
closely punctured striae, intervals feebly convex and with few minute 
punctures, the first interval broad, a little wider than those adjoining, 
instead of being distinctly narrower, as in other species of similar ap- 
pearance. Tilda' two-spurred, abdomen with six free ventral segments. 

Clivina impressifrons, Lee. 

(Plate II., Fig. 5.) 

This beetle is included among insects injurious to seed corn upon 
the evidence of a single observation made by Mr. F. M. Webster in In- 
diana. It is not uncommon in Illinois, and is found from New York 
and the north Atlantic States to Kansas and Kentucky. 

Nothing is known of its earlier stages. Most of our specimens are 
from electric-light and miscellaneous sweep-net collections, ranging 
from May 6 to November 15. 

The only recorded case of injury to vegetation by this beetle is re- 
ported by Mr. Webster in "Insect Life," Vol. III., p. 159. Under date 
of June 11, 1890, he says, "I received from Whitley county, Indiana, a 
considerable number of these beetles, with the statement that they were 
found m a piece of ground which had been broken the preceding spring. 
the field being swampy and of a black soil, like those infested by wire- 
worms. The beetles attacked the seed grains as soon as the latter be- 
came moistened. When received, one of the beetles had burrowed into a 
kernel of corn in the vicinity of the germ, and was engaged in devouring 
the substance/' 

In all probability this species, like others of the family, is essen- 
tially carnivorous in its ordinary habits. 

Description. — This beetle is 6 to 7 mm. long, and about one fourth 
as wide. It is rather depressed and elongate, shining dark red in color, 
tinged partly with blackish. The prothorax is not applied closely to the 
hinder part of the body, being connected with it by a short peduncle. 
The fore legs are very thick and strong, and the fore tibiae strongly 
toothed. In the row of spines on the outer edge of the middle tibia, is 
one of double thickness near the tip of the tibia. The prothorax and 
wing covers are parallel-sided, the former squarish, the latter sud- 
denly rounded off at tip, and with punctured striae. 



14 

3. Injuries by footless maggots, which burn themselves in the seed 

grain. 
Two rather common injuries to seed corn in the ground are due to 
small white maggots without legs, one apparently headless, with much 
the form and general appearance of a very small blow-fly larva, and 
the other with a smooth, conspicuous head of a shining jet black color. 
The first is known as the seed-corn maggot, and infests corn only, as 
at present understood; and the second is the black-headed grass mag- 
got, normally a grass insect, as its name implies, and injurious to corn 
only when this follows grass. Both these maggots penetrate the kernel, 
feeding on the mealy inner part, and leaving the outer shell. The first 
changes in the course of the summer to a small two-winged fly of the 
general form of the house-fly, and the second becomes a slender, small 
black gnat, roughly resembling the mosquito. The fly of the seed-corn 
maggot is little likely to be noticed in its winged state, but the gnat of 
the grass maggot is frequently seen in very large numbers on and near 
the ground in early spring. 

The Seed-Corn Maggot. 

(Phorbia fusciceps, Zett.*J 

(Plate II., Fig. 6 and 7 ; and Plate' III., Fig. 1 and 2.) 

This maggot penetrates the grain commonly after it sprouts but 
before it appears above ground, killing the germ or the growing shoot 
and finally hollowing out the interior so as to leave only the harder, 
outer parts of the kernel. In specimens of injured seed received by us 
from Altamont, Illinois, the larva had bored a round hole in the grain 
near the edge, and mined in a circular direction around the germ. In 
other grains it had entered at the tip of the germ, and in some beside 
the sprout. In one plant containing a full-grown maggot about two- 
thirds imbedded in the kernel, a rout about three indies long had form- 
ed, and a yellowish stalk had grown two inches in height. Still other 
grains had almost the whole interior eaten out. Unsprouted kernels, 
softened by lying in the earth, are also frequently penetrated in a way 
to destroy the grain. Commonly these injuries are trivial in amount, 
but in at least one instance mentioned by Dr. Riley in his First Report 
as State Entomologist of Missouri (p. 154), the crop of a field in New 
Jersey was practically destroyed. 

The adult of this insect is a small two-win sred fly. not unlike a 
house-fly in general appearance, but more diminutive and of a lighter 
form. The species is known at times to do considerable injury over 
limited areas. It is widely distributed, having been reported from New 
Jersey and New York to Indiana, Illinois, and Missouri. It was first 
described under the name Anthomyia zeas by Dr. Rilev, in his First 
Report as State Entomologist of Missouri (p. 154), his specimens hav- 
ing been reared from maggots sent him from New Jersey in 1868. 

Mr. B. D. Walsh next refers to this species in the American En- 
tomologist, Vol. I., 1869, (p. 224), maggots having been sent him from 
Eureka, Missouri. 

* Much additional information concerning this species has been lately pub- 
lished in Bulletin 78 of the Cornell University Experiment Station, Nov., 1894, 
p. 499. 



15 

In his First Keport on the Insects of New York (1888, p. 199), 
Professor J. A. Lintner gives a brief bibliography of the species and an 
economic treatment, following Riley j and Mr. F. M. Webster treats the 
species briefly in the Eeport of the Indiana Agricultural Society for 
1885 (p. 181). 

Life History. — The life history of this insect is as yet incomplete, 
no continuous experimental work having been done upon the subject 
throughout the year. Miscellanous observations and breeding-cage work 
at my office give us, however, evidence fairly complete that only a sin- 
gle brood occurs in normal conditions, the larva? of which have been 
observed from May 1? to June 13, and pupae from June 7 to 15, images 
emerging from June 11 to August 7. 

Description. Larva. (Plate II., Pig. 6.) — The mature larva is 
about 6 mm. long and 1 mm. thick at the widest part, which is near 
tiie truncate posterior extremity, the body nearly cylindrical from this to 
near the middle, thence tapering with increasing rapidity to the pointed 
anterior end. It is dirty whitish or yellowish white in color, the last 
segment darker. Twelve segments are distinctly seen, the surface of 
all except the first and last smooth and shining, concave, rising at either 
end into the sutural line, which is elevated into a ridge, especially thick- 
ened and prominent beneath, and provided throughout with numerous 
short transverse rows of minute scabrous points. 

The head is comparatively short and small, white and of a mem- 
branous appearance, alutaceous and transversely striated. The vertex 
is gibbous, but the front is deeply bifid. Each lobe bears at its apex a 
small sensory area in a dark ring, probably a rudimentary palpus; a 
short distance back of this is the antenna, which is two- jointed, the first 
joint tawny, about as long as thick, the second glassy and smaller. Be- 
neath, each lobe ensheathes the basal part of a long and slender black 
claw-like mouth-hook, curved strongly downwards and a little outwards. 
The black color of their adjacent bases shows through the skin of the 
posterior ventral surface of the head. The mouth opening is between 
the bases of these mouth-hooks. Between the lobes below, and extending 
forward into the mouth opening is an oblong body, with a small lobe 
lying parallel to it on each side, suggesting an imperfect labium with 
its palpi. 

The anterior stigmata are situated at the base of the second seg- 
ment on each side. The peduncle seems to be often drawn into the fold 
of the suture. It is short, and expands into a fan-shaped transverse di- 
lation, bearing on its outer margin six small globose lobes in a semi- 
circular row. In alcoholic specimens this segment is uniformly more 
than twice as long on the dorsal median line as on the ventral, causing 
the head to be directed downwards and forwards. 

The last segment is somewhat obliquely and sharply truncate, short- 
er above than beneath, less smooth than the preceding segments. Be- 
low is a large wrinkled dark tawny prominence, surrounding the trans- 
versely arcuate anal opening. The truncation is surrounded by twelve 
small pointed fleshy tubercles, disposed as follows: four equidistant 
larger ones on the lower margin, the middle pair the largest and trian- 



16 

gular; above these four on each side at about equal distances. The 
upper pair, one on each side, are slender and more distant from each 
other. Of the remaining three on each side the middle ones are on the 
margin of the truncation, but the other two are nearer the anterior mar- 
gin of the segment, and may easily be overlooked. On the ventral sur- 
face of the segment are four more; two distant ones just behind the 
anal prominence, and two placed close together in the concavity just 
in front of the large middle pair of the marginal series. 

The posterior stigmata are situated on a pair of flat-topped tawny 
tubercles lying near each other, a little above the center of the trunca- 
tion. There are three slits on each tubercle, radiating outwardly from 
a point near the inner margin. 

Puparium. (Plate II., Fig. 7.) — The puparium is shorter and 
thicker than the larva, being four to five mm. long and about 1.5 broad. 
It is fusiform, about equally and narrowly rounded at each end and 
reddish brown in color. The first two segments of the larval skin form 
a dark rugose convexity between the two anterior spiracles, which are 
as in the larva. The posterior tubercles are all present, but shrunken, 
surrounding the posterior stigmata, which become a little more promi- 
nent. 

Imago. (Plate III., Fig. 1.) — The following is the description of 
the female as given by Dr.Kiley: 

"Length 0.20 [inch (5 mm.)], alar expanse 0.38 [inch (9.5 mm.)]. 
Antennae black; style microscopically pubescent; front, fulvous, with a 
distinct, rather narrow, brownish cinereous margin; face and orbits 
brownish white; palpi and proboscis black; ocellar area somewhat 
heart-shaped; thorax and abdomen pale yellow-brownish cinereous, with 
minute black points at the insertion of the bristles; thorax with an in- 
distinct middle stripe of brown; legs black, tinted with cinereous ; poisers 
pale ochre-yellow; scales small, the upper valve larger than the lower." 

The Blach-headed Grass Maggot. 
(Sciara sp.) 

(Plate III., Fig. 3-7.) 

When the spring is cool and wet after corn-planting, so that the 
softened seed lies long in the ground without sprouting, this is especial- 
ly liable to certain kinds of injury: and it is under these conditions 
that the black-headed maggot seems most likely to affect it injuriously. 
Potting grain is, indeed, undoubtedly preferred by this insect, but it 
has occasionally been seen to infest kernels which had begun to grow. 
It lives normally in old sod, feeding chiefly, or perhaps altogether, on 
decaying vegetation there, and will be found in noticeable numbers in 
corn fields only where the field was in grass the preceding year. These 
maggots penetrate and hollow out the kernel, often leaving nothing 
more than an empty hull. A score or more of them may infest a single 
grain. 

They are also frequently noticed in rich garden ground and among 
potted plants, where they are accused by gardeners of eating the roots 
and hollowing out the bulbs. 



17 

The species is very commoi] throughout the State, and, doubt- 
less, throughout the country al Large, but it Has been noticed in its re- 
lation to grass and corn only in an article in my Thirteenth Report 
(p. 5;). 

Xu serious attempts have been made to determine the history of 
this species, but the following data from our scattered notes concerning 
the time of occurrence of its various stages art; worthy of permanent 
record. 

In hothouse and other indoor cultures it may continue to breed 
and grow the winter through. January 8, L889, imagos were observed 
living about a flower pot in my office which contained growing corn 
and wheat, and January 18 one fly was found with a string of sev- 
eral eggs yet attached to her ovipositor. On the same day nearly full- 
grown larva) and pupa? were found a little below the surface of the earth 
in the pot. Pupa? were noticed again February 11, these having come 
from larvae previously noticed feeding on rotting grains of corn. Feb. 
1, 1892, larvae of tins species were received from Mr. Benjamin Buck- 
man, of Farmingdale, Illinois, with the statement that they had mined 
nearly all his flower bulbs. The adult fly, he says, "seems to be a small 
fly or gnat, as this has been quite numerous about the pots all winter." 

The larva was first brought to my notice as a corn insect in May, 
1883, through Dr. Boardman of Stark county, who forwarded specimens 
to my office with the information that this insect was destroying newly 
planted corn in that county by eating out the substance of the germ, 
sometimes as many as three or four larva? to a single kernel. The field 
had been to pasture previously — partly blue grass and partly timothy. 
Other fields of the neighborhood were abundantly infested, but only 
wdiere the ground had been in grass the preceding year. 

May 30, 1883, the same larva was observed at Towanda, McLean 
county, abundantly infesting corn on old sod, and other similar ob- 
servations were made to July 10 of that year. 

Description. Egg. — Length, .31 mm. Oval, white, smooth, slightly 
flattened at the ends when they are pressed one against another. Ex- 
truded by the female in strings. 

Larva. — The larva is cylindrical, smooth, white, except the head, 
which is jet-black. The body is divided into twelve segments, not in- 
cluding the head, the three anterior of which are shortest, and are fre- 
quently somewhat retracted within each other. The terminal segment 
of the body is bent abruptly downward beyond the middle and con- 
stricted before the tip. The body is soft and flexible, and the move- 
ments of the maggot are sluggish. 

The head, viewed from above, is broad-ovate in outline, narrowing 
forwards, and somewhat abruptly rounded in front. It is smooth and 
shining, about as long as the first segment, within which it is frequently 
more or less retracted. Its width is about three fourths its length. The 
entire larva is one third of an inch in length when full grown, and ahout 
one fortieth of an inch in transverse diameter, and of nearly uniform 
size throughout, only the first two or three segments being slightly nar- 



18 

rower than those succeeding them. It is marked with neither hairs nor 
punctures, and provided with no locomotor structures whatever. 

Pupa. — Length 3.6 mm. ; greatest width, one third the length. In 
general color the pupa is yellowish white, the yellow predominating on 
the head and thorax. The eyes are black; antennae tinged with brown, 
which is darkest towards the base ; the front has two rather large prom- 
inent brownish tubercles or projections, one on each side of the median 
line, just above the base of the antenna?. A brownish bristle arises 
from each of the tubercles. Prothorax and anterior margins of the wing 
pads tinged with brown. The anterior stigmata are on the sides of the 
thorax, over the eyes, the antennas intervening in a broad transparent 
tubercle which contains in the center an oblong elevation with four 
elongate transverse black spots. Dorsum of thorax and abdomen with 
microscopically minute brown points. The penultimate segment has a 
lateral plication on each side, and the last segment is bilobed beneath, 
with a pair of conical prolongations, thickly beset with scabrous points, 
extending backward from each side. 

Female. — Length 3 mm. exclusive of ovipositor, which is about .6 
mm. in length. General color blackish. The head is black; antennas 
brownish black, with sixteen cylindrical joints united by very short 
pedicels, and covered with short white pubescence; occiput and front 
black ; palpi and proboscis dusky yellow. Thorax black and moderately 
shining; pleura? brownish black; halteres pale yellowish; legs yellow, 
with black hairs; coxse with golden hairs; femora with black spot on 
the under side at base, tips of tibiae and tarsi dusky, hinder tarsi almost 
black; middle and hind tibia? with yellow spurs at tip; wings hyaline, 
veins brownish yellow, branches of fork almost equally curved. Abdo- 
men dusky blackish, paler on ventral surface. Ovipositor dusky, with 
two pale yellowish lamella? at tip. 

Described from alcoholic specimens. 

4. Injuries by six-legged larvae which gnaw or bore 
through the kernel. 
The six-legged insect larva? which infest corn in the earth arc of 
very unequal importance, the so-called wireworms being found more 
injurious to seed corn than all other insects taken together, the larva 
of the banded Ips being only occasionally reported to infest corn in the 
earth, and the other — that of the pale-striped flea-beetle — having been 
seen but once in this situation. Probably ninety-nine per cent, of the 
six-legged kernel-eating insect larva? will be found to be wireworms of 
one or another species; and the greater part of these will usually be- 
long, in Illinois at least, to a single species (Melan&ius rrihuUsus), 
which may well be called the corn wireworm. 

Pale-striped Plea-beetle. 

(Sysiena twniuhi, Say.) 

(Plate III., Fig. S; and Plate IV., Fig. 1 and 2.) 

The larva of the pale-striped flea-beetle is a stiff, sluggish insect, 
slender and small, less than a fourth of an inch in length and about one 
eighth as wide, dull, of a very pale yellowish color, minutely roughened 



19 

and hairy, the thoracic segments with a regular geometrical pattern of 
longitudinal depressed lines. It is also distinguished by its peculiar form, 
which narrows noticeably from behind forward, the head being very small. 
In the only case in which it was found infesting growing corn 
(Champaign, May 17, 188G)* the larva had partly buried itself in the 
kernel beside the sprout. This and others of the species found among 
the roots were bred to the beetle stage on sprouting com, pupating May 
26 to June 7 and emerging as adults on the 17th of June. The great 
abundance of this insect in the beetle stage — so common as often to 
keep the leaves of the cocklebur peppered with small holes where these 
beetles have fed— makes even so slight a hint of its capacity for mis- 
chief both interest in-- and important. The adult insect also feeds on 
corn, as reported by Gloverf on the authority of a correspondent, ac- 
cording to whom these beetles nearly destroyed a field of corn at Cham- 
bersburg, Pa., eating the leaves and leaving the bare stalks standing. 
The edges of the leaves may be gnawed away, sometimes nothing bin the 
midrib being left, or the leaf may be riddled with small holes. 

The agricultural injuries of the beetle are not confined to the corn 
plant, however, but it has been found by various entomologists to feed 
on beans, potatoes, beets, clover, strawberry and blackberry leaves, and 
the muskmelon, among useful plants; and also on purslane, cockle- 
bur, plantain, ragweed (Ambrosia), pigweed (Amarantus) and lamb's- 
quarter s ( Chenopodium ) . 

Adults of this species have been taken by us at frequent intervals 
from April 8 to September 2, much the most abundantly in June and 
July. Our substantial knowledge of its life history depends, however, 
on the single breeding experiment already mentioned. Four larvee were 
collected May 17, 1886, and placed at once in breeding cages with 
sprouting corn. May 26 a pupa was found lying on the earth in the 
cage. June 7 another pupa was noticed yet in the earth, and on the 
17th of June three adults had emerged, and one pupa about mature 
was taken from the cage. 

Description. Larva, (Plate IV., Fig. 1 and 2.)— Length 5 mm., 
greatest width about .6 mm. Slender, widening gradually to the 11th 
segment, thence tapering quite rapidly. General'" color pale yellow or 
brownish yellow, paler towards the posterior end. Head yellowish 
brown, with numerous stiff hairs; jaws darker brown. Antennse three- 
jointed, pale, short, and thick. The thorax and abdomen are darkest on 
the dorsum, fading to paler on the margins and ventral surface, and the 
latter very pale yellowish at the end. The first thoracic segment has 
two longitudinal curved impressed lines on the dorsum; segments two 
and three have longitudinal impressed lines on each side near the border, 
between which is a transverse curved line crossing each segment near 
its anterior margin, from which two oblique straight lines extend to the 
posterior margins of the segments. The legs have stout, blunt, spine-like 
processes on their anterior surfaces, and stiff hairs on the posterior. The 
abdominal segments are transversely wrinkled on both anterior and pos- 
terior marg ins. The skin is shagreened, and the whole body is evip- 

Dec.,* mT a Vo1 n Il Ent0 ' 1 7 ! 4° giSt '" 1SS6 ' V ° L 1S< P - 177; " Entom °Sica Americana," 
t Hep. Com. Agr.,' 1873, p. 152. 



20 

plied with stiff, spine-like hairs of various lengths. The anal segment 
has a single fleshy proleg. When seen from above this segment rapidly 
narrows to midway its length, the posterior half forming a rounded, 
lobe-like projection of about one half the width of the anterior portion 
of the segment. On the projection are four long, stiff, spine-like hairs 
and a marginal crown of shorter spine-like processes, each of which 
ends in a fine, curved, hair-like lash. (Described from two specimens.) 

Pupa, — The pupa is 3.5 to 4 mm. in length. It is pale yellowish 
in color, naked, and furnished with scattered stiff hairs of considerable 
length. The wing-pads, antenna?, and legs are folded obliquely over the 
ventral surface. The abdomen ends in a pair of rather long, tapering, 
brown spines, which are very thick at the base. In the older specimen 
the black eyes and dusky marking of the wing-covers show through the 
thin pupal skin. (Described from two specimens.) 

Imago. (Plate III., Fig. 8.) — Length 3-4.5 mm. Elongate oval 
in shape, with a shining surface. Color very variable, ranging from 
almost black to entirely pale brownish, the pale variety being the com- 
mon form in Illinois. The head is dull rufous, with a few punctures; 
antenna black. The thorax is pale, with a few faint punctures on the 
surface, a distinct posterior transverse impression, not limited at the 
ends. 

The legs are dull reddish or testaceous, the hind legs fitted for leap- 
ing. The wing-covers are finely densely punctured, not striate, and 
each has a whitish longitudinal stripe on the middle, extending nearly 
to the apex. These stripes are visible on even the palest specimens. 
The variety blanda- has the under side of the body and the sides of the 
thorax narrowly piceous. 

The preceding descriptions of larva and pupa were drawn up by an 
assistant, Mr. John Marten, from the office specimens, not accessible 
as I write. 

The Banded Ips. 

(Ips fasdatus, Oliv.) 

(Plate IV., Fig. 3-5.) 

Among the insects attacking the kernel in the earth, is the hitherto 
unclescribed larva* of a beetle, Ips fasciatus, which in the adult state 
is abundant everywhere, feeding upon a great variety of vegetable sub- 
stances, fresh or in a state of decay. The adult beetle has long been 
known as occasionally and slightly injurious to corn in the ear; but the 
fact that the larva may infest seed corn after planting, although first 
noted by us in 1883, has not hitherto been published. 

My first observation to this effect was made at Normal, 111., June 
18 of the above year. In a field of corn a part of which had been in 
pasture for fifteen years preceding, while the remainder had grown 
turnips the year before — which, however, had not been removed from 
the ground — large numbers of these larva? were found in and about 
the seed kernels.f From the first, stalks were growing fully two inches 
high. Occasionally a larva was seen in the space between the rows, but 

* Although the larva of this beetle was rudely figured many years ago (Pack- 
ard's Guide to the Study of Insects, p. 4 44), the immature stages of the species have 
not anywhere been described. 

t The field had been twice planted because of a partial failure of the first seed, 
and the kernels of both plantings were infested. 



21 

nearly all were concent rated in the hills of corn. Considering the ordi- 
nary habit of the species, it is quite likely that the beetles were attracted 
to this tield by rotten turnips remaining- in the ground. 

June 16, L885, Laivse were very abundant at Mt. Pulaski, in Central 
Illinois, in the kernels of ears left in the field which had been turned 
under by the plow and had commenced to grow. May 16, 1887, a num- 
ber were taken in a similar situation from a mass of sprouting corn at 
Urbana, 111. 

As an adult, this species was reported by Walsh in 1867,* on the 
testimony of an anonymous correspondent, to have done an extensive 
injury some years before to sweet corn in Minnesota by burrowing in 
the ear; and Dr. John Hamilton, of Toronto, Canada, saysf that it is 
often found in the green ears of maize, but only in such as have been 
injured by birds or other animals. September 13, 189)3, it was brought 
to my office by an assistant, Mr. Marten, with several injured kernels 
of corn, from the exposed tip of the ear, which the beetle had burrowed 
into or eaten away irregularly. In one other case reported under this 
same date it was found burrowing into doughy grains beneath the husk, 
more than an inch from the nearest exposed kernels, the natural in- 
ference being that the grains had not been previously injured. This 
very common species must consequently be classed as one of the minor 
insect enemies of corn, which it injures both as larva and adult — much 
more seriously, however, in the former stage. 

Injuries to other valuable plants and fruits were first reported by 
Walsh in 1867,J to whom a correspondent sent the beetle with the state- 
ment that it had eaten into apples and pears, apparently burrowing in 
holes made by some other insect or a bird, as many as ten or twelve 
occurring in a single hole. A similar report as to the pear was made 
in 1870 by a correspondent of Dr. Eiley, who found the beetle entering 
the fruit by way of the calyx. § 

By Dr. Cyrus Thomas, State Entomologist of Illinois, it is said** — 
again on the authority of a correspondent — to have injured apples in 
1876 — principally the early varieties, puncturing the skin, and eating 
its way to the center, dozens of them being sometimes found in a single 
apple. By one of my most valued correspondents, Mr. Benjamin Buck- 
man, of Farmingdale, 111., this beetle was reported to me July 14, 1884, 
as a "never-ending nuisance from eating into ripe apples, pears, rasp- 
berries, blackberries, etc.," on his place. 

By Packard it was said in 1883 to occur in the roots of the squash, 
seemingly in both larva and imago states ;ff and Dr. Lintner, State 
Entomologist of New York, mentions in his Sixth Eeport (p. 188) the 
receipt from Prof. C. H. Peck of several examples of this species taken 
July 4, eating into squash vines. Other foods of the adult are decaying 
corn stalks, cabbage, and other plants, the oozing sap of trees, the blos- 
soms of composite plants, and the pollen and anthers of corn.- It fre- 
quently follows the corn worm and other burrowing larvae into corn and 
other vegetation, feeding probably upon exuding sap and excrement ; 

* Prae. Ent. Vol. II., p. 56. 

f Can. Ent. Vol. XVII. OSS5). p. 16. 

t Prac. Ent. Vol. II., p. 56. 

§ Araer. Ent. Vol. II., 1870. p. 308. 
** Sixth Rep. State Ent. 111.. 1875-76, p. 91. 
tt Guide to Study of Insects, 1883, p. 445. 



22 

and it occurs in the apple in the burrows of codling moths. It is also 
an occasional pest in the pantry, infesting bread and other cooked foods. 

The feeding habits of the larva are much less known, the single 
doubtful statement of Peck as to its occurrence in squash vines being 
the only published record I have seen. Our own notes show, besides its 
occurrence in corn, that the larvae breed in rotten apples, specimens 
having been reared by us from crab apples in 1885. 

The annual number of its generations has not been determined, but 
our breeding notes tend strongly to establish the occurrence of more 
than one brood in a year. Adults have been collected by us as early as 
March 10 to 14 (1885), at which time they were hibernating under 
leaves, and as late as November 15 (1884), when they were taken from 
piled-up driftwood and leaves near a slough. In both cases the beetles 
were evidently in winter quarters. Our numerous collection records 
show that the species is common in the adult stage in Central Illinois 
through April and May and until about the middle of June. May 16 
is our earliest date for the observation of the larva, other examples 
occurring from June 16 to 20. By the middle of July the beetles again 
become abundant, continuing common throughout the remainder of the 
year, our dates of capture at this season ranging from July 10 to No- 
vember 15. Larvse of what is probably a different generation from those 
mentioned above were collected by us in crab apples and transferred to a 
breeding cage. October 6 larvge, pupse, and imasros were taken from this 
cage, and by the 16th others had completed their transformations, and 
still others by the 21st. 

It appears from these observations that the species hibernates as an 
adult, and that it gives origin during the year to at least two genera- 
tions,* breeding in corn, apples, and doubtless other vegetable sub- 
stances. 

The larva enters the earth to transform, making a friable earthen 
cell. 

Description. Larva. (Plate IV., Fig. 3.) — Length 5 to 6 mm., 
width slightly less than 2 mm. Elongate, oblong, depressed, sides nearly 
parallel; general color brownish testaceous, surface minutely granulate, 
the more exposed portions above and below finely punctate; covered with 
dense short grayish pubescence except the head and the greater part 
of the first and last segments, which are smooth. Twelve distinct seg- 
ments besides the head. 

Head four fifths as wide as the first thoracic segment, and four 
fifths as long as broad, dark red-brown. Front with two sulci arising 
at the bases of the mandibles, converging slightly posteriorly, and united 
behind by a transverse sulcus. Four shallow impressions are grouped 
about the center of the space included by the sulci. The clyneus is 
indistinctly separated from the front, deeply impressed at middle : the 
labrum transverse, concave, elevated at sides, emarginate in front, it 
and the clvpeus with a setigerous puncture on each side. The mandi- 
bles are rather long and not stronglv curved, broadlv emarginate near 
middle of exterior margin. The maxillary palpi have three nearly equal 
joints, about as long as thick, except the last, which is a little longer 

* See also Caulfield, Can. Ent., XX., p. 198. 



and slenderer. The maxillary lobe is short and thick, the end rounded, 
fringed with a dense brush of shorl erect hairs. The ligula is small 
and short, the labial Dalpi small, of two joints, the first shorl and thick, 
the second more slender, nearly three limes as long as thick. The gular 
sutures, mentum, and base of maxillae, are usually outlined in darker- 
color. The antenna' are four-jointed, the first short and very broad at 
basej the next two about equal in length, the second a little longer than 
thick, the third more slender, the fourth subulate, shorter, home at the 
upper side of the apex of the third, which also hears below this a small 
accessory article ahont hall' the length of the fourth. Eyes wanting. 

First thoracic segment reddish brown, with the posterior border 
minutely rugose-granulate, extending forwards in a point upon the 
median line: anterior margin narrowly rugose, remaining surface smooth 
and shining; one half longer than the next segment on mesal line; this 
latter and the following segments, except the last, similar in size and 
vestiture. The surface of the abdominal segments is varied by naked 
impressed lines, finely transversely ridged, as follows: a dorsal row of 
Y-shaped impressions, one at the anterior edge of each segment; a sub- 
dorsal row of oblique impressions; and a lateral impressed line, inter- 
rupted at the sutures. Beneath is a similar pattern of sculpture. The 
spiracles are raised upon short subcylindrical shining tubercles. The 
first pair are at the extreme anterior lateral angle of the second thoracic 
segment. The remaining nine pairs are upon the abdominal segments, 
a little higher upon the sides. The first ones are nearer the anterior 
margin of the segment, hut posteriorly they approach the hind margin, 
and those on the penultimate segment are longer and project backwards 
beyond the posterior margin of the segment. On the last segment they 
a pi iea i' as two slender black-tipped tubercles on the upper surface. 
Beneath the tubercles, and nearer the hind margin of each segment, is 
a pubescent tubercle. The last segment is about two thirds as wide as 
the preceding one, semicircular, shining, colored like the head, bearing 
posteriorly a pair of stout hooks projected backwards and curved up- 
wards, with a strong inner seta-hearing tooth near tip, not as long as the 
tip itself, which also hears setae. Legs rather short, four-jointed, with 
a single claw. Anal proleg short, cylindrical. 

Pupa. (Plate IY., Fig. 4.) — Length 5 mm., greatest width 2.2 mm. 
Elongate-oval, tapering posteriorly, brownish testaceous; head, wing- 
pads, and legs usually paler. Surface subopaque, minutely and densely 
punctate, and very minutely pubescent, with smooth spaces at bases of 
wing-pads and on metathorax. 

Vertex of head with a pair of large spines on each side. Just over 
each eve is a pair of minute spines, and in front of these another pair 
on each side. The labrum is rather strongly notched. 

Prothorax with four spines on the anterior margin; the inner 
largest of all ; four spines on each side, one at each angle, and the re- 
maining two nearer the angles than to each other. Within the line of 
marginal spines are three smaller ones on each side of the disk. The 
scutellum is three fourths as long as the metathorax, which is as long as 
the first three abdominal seo-ments, and is longitudinally sulcate at 
middle. The elvtra reach to the hind knees, and the hind tarsi reach 
—3 E 



2i 

the posterior margin of the fifth segment. The wings attain the middle 
of the sixth segment. 

Each abdominal segment bears on each side a long spine on its 
lateral edge, situated near the middle on the first seven, and at the 
posterior angles of the last two, pointed directly backwards on the last 
segment. The spiracles are rather large, circular, slightly elevated on 
broad tubercles, darker colored and conspicuous on the first five seg- 
ments, indistinctly visible on the remainder. Just above these on each 
segment, is a strongly elevated carinate ridge, also bearing a spine, 
except on the last segment. The spines are small, except on the seventh 
and eighth segments, where the ridge becomes enlarged and overhanging, 
and the spines large. The first four segments are short, nearly equal, 
about twelve times as wide as long; the fifth and sixth are each about 
twice as long as the second, the sixth a little the longest. The seventh 
segmenth is subtrigonal above, with curving sides; the eighth conse- 
quently arcuate and narrow, obtusely pointed behind at middle; the 
ninth a little longer, less than 'half the width of the seventh, and trun- 
cate posteriorly. Beneath, the seventh segment is the longest, and the 
eighth is very short, especially at middle. 

Adult. (Plate IV., Fig. 5.) — Length 5 to 6 mm. Body elongate- 
oval, smooth, moderately shining, black, evenly and finely, but not 
densely, punctured. Wing-covers with four yellowish spots, one at the 
base and one near the tip of each. These vary in extent and color. The 
wing-covers are subtruncate at apex, exposing the tip of the abdomen 
above. 

WIREWORMS. 

(Elatekid^e.) 

Failure of the seed to start, or a sudden withering of the corn plant 
when a foot or two in height, especially if the field was broken up from 
grass one or two years preceding, are always sufficient to warrant a sus- 
picion of injury by wireworms. These hard, smooth, shining, reddish 
or yellowish brown cylindrical six-legged larva?* are indeed much more 
destructive to seed-corn, under ground, in Illinois than all other insects 
taken together. They may begin their injuries to the seed almost im- 
mediately after planting, commonly burying their heads in it at first, 
sometimes eating entirely through the kernel, and even devouring it 
completely. If they attack the growing plant they are likely to eat the 
smaller roots, or to penetrate or bore through the larger ones, dwarfing 
or killing the corn; and later, when the young nlant is several inches 
high, they frequently kill it outright by boring their cylindrical channels 
directly through the underground part of the stalk. They are far the 
commonest in corn on ground which has lain for several years in grass, 
and are much more likely to do serious mischief the second year after 
the breaking up of the sod. They should be sought for diligently on 
such lands whenever the seed fails to grow, or when the sudden wither- 
ing of the plant hints at a serious damage to it under ground. At such 
times practically all the wireworms in the field will be found in the hills 

* This general description of the wireworms does not apply to one very peculiar 
form (Cardiophorus) taken but once in Illinois, and described on pages 28-29. 



of corn or in their immediate vicinity, sometimes as many as ten or a 
dozen in each hill. 

Although wixeworms are rarely distinguished by farmers as of 
different kinds, there are no less than one hundred species of these 
insects known to occur in Illinois in the adult, -or beetle, stage, and 
eight species of the larva? (the so-called "wireworms" themselves) have 
been found by us here injurious to corn. These corn wireworms have, 
however, so strong a family resemblance that they are little likely to be 
confused with any other insect by the fairly good observer who has once 
learned to recognize any one of them. They vary in length, when full 
grown, from half an inch to an inch and a quarter, but agree in their 
hard, crust-like surface, nearly destitute of hairs; their brownish color, 
varying from yellowish to reddish; their slender bodies, distinctly seg- 
mented, and of about equal diameter throughout their length; their 
flattened heads, with jaws borne in front and extending horizontally 
forward ; the six pairs of short, stout, jointed legs on the three segments 
following the head; the absence of legs of any kind on the eight seg- 
ments thereafter; and the single sucker-like proleg on the under surface 
of the last segment of the body — the thirteenth, counting the head as 
one. This terminal segment is often peculiarly finished above — concave 
or convex, notched, toothed or lobed at the sides and end, or, in one 
species, with a pair of conspicuous round openings on the upper surface. 
Taken in the fingers, the wireworms bend and wriggle with surprising 
strength, and easily slip out of the grasp. 

They live regularly and normally in grass lands, feeding on roots 
of grass, where, however, their numbers are rarely sufficient to produce 
any notable effect upon the sod. It is only when concentrated in the 
comparatively scanty vegetation of a field of young corn in spring, or 
occasionally in young wheat or other small grain, that they do any very 
marked or important harm. They are to be found in grass of every 
description, from prairie sod and the coarse and rank sedges along the 
borders of marshes, to the cultivated grass of our pastures and meadows. 

The commonest form of attack on the corn, as seen by the farmer, 
is, perhaps, the burrowing of the worm into the seed kernel, either before 
or after it has sprouted. All the species treated in this paper have been 
seen with their heads buried in the kernels, either in the field or in 
breeding cages. Frequently attacks in the field have been so severe, par- 
ticularly the first or second year after the sod has been broken, as to 
require planting a second or third time. Drasterius el e guns and Melano- 
sis fissilis have been taken in the act of perforating stalks just above 
the root. In a field at Peru, Illinois, examined in July, 1883, as much as 
six per cent, of the corn in the field had been killed in this way, some- 
times two or three larva? being found in a single stem. 

The roots of the corn are also eaten to a greater or less extent by 
all the species, the damage from this cause being sometimes quite con- 
siderable. A field in Alexander county visited in June, 1886, bad spots 
of one hundred to two hundred hills not more than a foot high, while 
the balance of the field was four or five feet high. Many hills in these 
spots were gone. In the smaller hills many, small, slender, peculiar- 
looking larvae of an unknown species of Oardiophorus were found. Tn 



26 

some instances they had almost completely destroyed the roots of the 
corn; in others the roots were bored through and the outer surface eaten 
away so as to almost destroy their usefulness. 

Agriotes mancus is so destructive to wheat as to be known as the 
"wheat wireworm." - Drast&rius elegans is also known to infest this 
crop, as do other species as well. Rye, barley, and oats also suffer from 
wireworm attacks. Dr. Fitch also found them burrowing in timothy 
bulbs. Larvae taken from a dense clover sod and placed in our breeding 
cages, where they were supplied only with grass and clover, gave us 
imagos of Asaph&s decoloraius. 

Among root crops, potatoes often suffer from being bored into and 
by having the surface gnawed and corroded by the worms; but turnips, 
it is said, appear to be more infested by them than any other root crop. 

Besides the crops already mentioned Dr. Fitch names the following, 
which the wireworms are known to attack or are recorded as attacking: 
mangel-wurzel, cabbage, carrots, beets, onions, lettuce, rape, hops, straw- 
berries, pinks, carnations, dahlias, lobelias, and numerous other garden 
flowers. They have also been reported to me by a horticultural friend 
as destroying planted peach pits in the earth. 

The injurious species agree fairly well in the main features of their 
life history, changing to the dormant pupaa in the earth in July or 
sometimes in August, and changing again some three or four weeks 
later to the brown or reddish beetles commonly known as "click beetles" 
or "jumping jacks'' — hard, somewhat hairy insects, of slender oval 
form, distinguished at once by their peculiar habit of springing into the 
air with a sudden click when placed upon their backs. A large part of 
these fully developed beetles remain under ground until spring, enjoying 
there the protection of the oval earthen cavity or cell formed by the 
larva as a preparation for pupation. A part, however, come forth from 
the ground in fall, passing the winter in sheltered places, and the re- 
mainder emerge in spring, laying their eggs most commonly in grass 
lands in the earth. Of their subseqnent life history little is yet definitely 
known. It seems certain that all live more than one year as wireworms 
in the earth, and observation of the various sizes of larva? of the same 
species to be found in the field at once, usually supports the common 
impression that the period of life in the larval stage does not extend 
beyond two years ; a fact which, taken in connection with the death and 
decay of grass roots the first year after breaking up the sod, serves to 
explain the greater damage done by wireworms the second year the 
ground is in corn. The number of wireworms having been little dimin- 
ished since the crop was changed, and their original food having 
practically disappeared, they are compelled to concentrate upon the corn 
— either the newly planted seed or the young plant while it is still very 
small. 

The species of wireworms have by no means all been identified by 
breedino-, but a good beginning has been marie in this useful work at my 
own office and at the Cornell University Experiment Station. As a 
present aid to discrimination of forms I here present an outline of dis- 
tinctive characters drawn up by my office assisstant. Mr. C. A. Hart. 



27 
GENERIC synopsis OF WIREWORMS. 

it is not surprising, in view of the slighl differences which separate 
some of the larger groups of Elateridae, that their Larvae should fail to 
fall naturally into the same grouping; and it is probable that a Euller 

knowledge of larva] characters will show thai the natural relationships 
of several genera arc differenl from those now accepted. 'The larva' of 
Elateridae do not all have the same habitus. Those of the Eucneminse 
so tar as known cesemble larvae of Buprestidae. Melanactes is also quite 
unlike a wireworm, and the Cebrionini, as represented by Cebrio, have 
peculiarities which distinguish them from typical wircwornis. Exclud- 
ing these forms, the Illinois genera whose larval history is known may 
be grouped as follows : 

The genera related to Alaus, and. also some of the Klaterini, possess 
a pair of curved hooks, one each side of the anal proleg, called the scan- 
sorial hooks, which are absent in the other Elaterini; and the last seg- 
ment usually hears two backward prolongations, or cerci. In Elater and 
related genera, also in Agriotes, the last segment is more or less round- 
ed-conical ami pointed, without cerci. In Melanotus it is flattened above 
and pointed. In the remaining (Jorymbitini, except Melanactes, the 
cerci are well developed. The following table can only be regarded as 
provisional until a greater number of species are studied. 
Scansorial hooks present. 
Cerci present. 

Anal proleg denticulate each side. 

Muscular impressions* conspicuous on thorax and abdomen, 

ovate on the latter ( 'halcolepidius. 

Muscular impressions obsolete on thorax, narrow and curved 

on abdomen Alans. 

Anal proleg unarmed except with the scansorial hooks. 

Abdominal muscular impressions obovate, last segment bear- 
ing minute setigerous tubercles above Agrypnus. 

Abdominal muscular impressions linear, last segment ru- 
gose above, without setigerous tubercles, apical notch 

acute Drasterius. 

Xo cerci, larva long and moniliform Cardiopliorus. 

Scansorial hooks absent. 
No cerci. 

Xo black pits at base of last segment. 

Muscular impressions linear, indistinct, not striate, last seg- 
ment conic, terminated by an acute point Dolopius. 

Muscular impressions distinct, sharply striate. 
Last segment ovate-conic. 

Smooth, tip of last segment rounded Ludvus. 

Punctate, tip of last segment with an acute point. .Elqter. 

Last segment flattened, and with a subdentate margin api- 

cally Melanotus. 

* Small, striated areas, a pair to each segment, above the spiracles, near the 
anterior margin, usually oblong- in shape, and each marked with equal, parallel ridges 
and grooves, extending in the direction of the long axis of the segment. 



28 

A pair of black pits at base of last segment, which is ovate- 
conic and pointed Agriotes. 

Cerci present Athous, Corymbites, Asaphes, Cryptohypiws; 

We have recognized five or six species of Melanotus larva', two of 
which are definitely identified, and may be separated by the following 
key. Both have the body very finely and sparsely punctate, and the 
last segment finely tuberculate. 

Last segment finely, sparsely, and indistinctly punctate above, 5- 
dentate apically, strias of muscular impressions at middle of body 
12-14, sometimes fewer in younger specimens (PI. VI., Fig. 

4, 5) cum in mi is. 

Last segment distinctly and rather coarsely punctate above, trian- 
gulate or feebly trfdentate apically, strife of muscular impressions 
at middle of body 4-5, rarely fewer (PL VI. Fig. 6, 7, 8) cribulosus. 
A larval skin like that of cribulosus, but with the apical teeth more 
narrow and prominent, especially the median one, was found in a pupal 
cell with a fine male M. americanus. Another species frequently found 
in rotten wood, has the surface strongly punctate. 

Caediophokus sp. 

(Plate IV., Fig. 6.) 

A very peculiar long and slender elaterid larva, quite unlike a wire- 
worm in general appearance, although belonging to the same family 
and doing the same mischief in the corn field, was found by me in 1886 
mining and perforating the roots of corn in the sandy soil along the 
Mississippi in Alexander county, Illinois, with the effect to greatly delay 
the growth and permanently dwarf the corn. Although known only as 
a root insect, it probably attacks the kernel earlier, and its description 
is given here with that of other members of its family. It may be distin- 
guished at once from any other larva likely to occur in the same situa- 
tion by its very long and slender form, and by its nodulated appearance, 
due to the expansion of a part of each segment. 

It is evidently capable of very serious injury to corn, channeling 
and burrowing the roots in every direction, and often causing decay — 
much more serious than the immediate mechanical injury of their min- 
ing. The perforations through the surface of the root were in some 
instances so numerous and close as practically to deprive the plant of all 
use of its roots. 

The number of larvas found in a hill varied from one or two to ten 
or twelve, and their great activity in the ground — through which they 
moved with ease — suggested the probability of their going from hill to 
hill, as their necessities required. This genus has never been reported 
in the larval state in this country except on the occasion mentioned, and 
then on no other plant except corn. Search among the roots of other 
plants in the infested field, — pigweed (Amarantusj, purslane, pigeon- 
grass, cocklebur, etc., — failed to discover them. 

Description. — It is nearly an inch long when full grown, and scarce- 
ly a millimeter (.04 inch) wide, whitish in color, becoming yellowish 



29 

on the thorax and darker yellowish browD od the head, sparsely clothed 
with long hairs. The head, including the mouth parts, is nearly three 
times as long as wide, with the sides almost straight. The clypeus is 
greatly elongated, the posterior portion linear and tapering almost to a 
point behind, the anterior part (epistoma) rectangular, one third longer 
than wide, behind marked oil' by an impressed line, in front notched at 
middle, bearing a fringe of short hair each side of the notch, and emar- 
ginate behind each antenna. The antennae are robust, flattened above, 
the first joint subtriangular, but little longer than wide, the second 
oblong, twice as long as the first, its apex obliquely truncate, making the 
outer side the shortest. At the inner angle of its apex is attached the 
very small Third joint, which is directed obliquely outward; and near the 
outer angle is placed an accessory joint. No trace of ocelli appear. The 
mandibles are about half as long as the head, dark brown, vertically flat- 
tened, deeply grooved, cleft half-way to the base into two branches, one 
above the other, parallel and nearly straight, their apices slightly 
curved outwards. The upper branch bears on its inner edge three sharp 
teeth directed mesad, with a small denticle on each side of the proxi- 
mal one. The maxillae are slender at their bases, which are provided 
with numerous long hairs, and are scarcely separated by the very slender 
labium. The prominent excurved four-jointed maxillary palpi are in- 
ferior, and the inner maxillary lobe with its brushes of long yellowish 
hair is superior. Between the maxillae extends the very slender distal 
portion of the labium, with diverging two-jointed palpi at tip. Thoracic 
legs lather stout and long, and furnished with long hairs on the coxae 
ami femora, the latter with about three small spines on the under side 
towards the apex. The tibiae each have one or two small spines below, 
and several short brown spines at the tip. 

The first eight abdominal segments are similar, and consist of three 
divisions each, except that the first division of the first abdominal, and 
the last division of the eighth, are wanting. The middle division is 
wider and subglobose; the other divisions are narrower and subcylindri- 
cal, the anterior short, the posterior as long as the middle portion. All 
the abdominal segments are marked below with seven longitudinal sul- 
cations, the median smaller than the rest on the posterior division, and 
reduced to a fine impressed line on the anterior division, on which the 
inner pair of sulci are lacking. The outer pair are lateral, and nar- 
rower, except on the middle division, where they contain the concolor- 
ous spiracles. On the middle portion of each segment beneath, in the 
pair of sulci next to the median one, is a pair of plicated oblong promi- 
nences used in crawling. The ninth segment is two fifths longer than 
the eighth, and the climbing hooks which accompany the prolegs are quite 
prominent. This segment ends in a rounded lobe-like projection clothed 
with long hairs. 

Drasterius elegans, Fabr. 

(Plate V., Fig. 1-3.) 

This wireworm, the smallest of the species infesting corn, was re- 
ported as exceedingly abundant and injurious to young wheat in Indi- 



30 

ana in 1889.* The first mention of it as an insect injurious to corn 
which has come to my notice, is contained in the Keport of the United 
States Entomologist for 188?, p. 151, in the nature of a note by Mr. 
Webster to the effect that he had twice surprised larvae of Drasterius, 
supposed to belong to this species, with their heads inserted in the stems 
of young corn. Mr. Wm. H. Ashmead also reportsf that the corn fields 
of certain counties of Maryland were found to be badly infested by two 
insect larvae, one of which he considered as possibly that of D. elegans. 

It was liist found by me in corn fields August 18, 1882, at Elmira, 
Illinois, in the course of a field study on the corn root worm (Diabrot- 
ica longicomis). It was taken again from the roots of young corn at 
.Normal, Illinois, June 17, 1881, and also in Champaign county June 
11 of the following year, and June 5, 1G, and 29, 1886. June 26 of the 
last year it was collected from growing corn at Cairo, Illinois, where it 
was associated with great numbers of another and more injurious wire- 
worm (Cardiophorus). An individual was seen May 16, 1887, at Cham- 
paign, Illinois, among the roots of corn, eating a kernel of sprouting 
corn; and another was taken a few days later among the roots of corn, 
following sod, in such connection with an injured kernel as to leave 
little doubt that it had been eating it. It occurred again in corn-field 
collections from the earth, made at Champaign May 29 of that year, and 
in others made June 20, 1888. The extent and amount of its injuries 
air as yet unknown, the data collected serving merely to show its pres- 
ence and injurious habits in corn fields following grass. 

This is the smallest of the wireworms, measuring when full grown 
less than half an inch in length. It was first identified by breeding by 
Comstock and Slingerland in 1891, as reported in their Bulletin 33 of 
the Cornell University Agricultural Experiment Station, published in 
1891. 

Description. Larva. (Plate Y., Fig. 2 and 3). — "The larva? are 
small, 9 mm. to 12 mm. in length, sparsely hairy, and considerably flat- 
tened in form, tapering slightly toward the extremities. The body is of 
light waxy yellow color, with the head and following segment consider- 
ably darker. A deep linear mesal impression extends along the dorsum. 
The mandibles are rather large and not toothed. The caudal segment is 
much flattened, and has a nearly heart-shaped caudal notch formed by 
two short, broad projections that curve upward, each of which terminates 
in two short, blunt, horny, diverging tubercles. The dorsum of the seg- 
ment is bounded by a narrow ridge which, at the sides of the segment, 
bears five or six short, horny tubercles. The oval area bounded by this 
ridge is strongly convex cephalad, and deeply concave caudad. This 
area is marked by two distinct linear impressions diverging slightly 
cephalad from which many fine wavy wrinkles radiate. The proleg is 
large, hairy, and has no raised ridge around its base, but the segment is 
deeply excavated just back of it." \ 

* F. M. Webster in Bull. 22, Div. Ent, U. S. Dept. Agr., p. 52. 
t "Insect Life," Vol. Ill (1890), p. 54. 

t Comstock and Slingerland, in Bull. 33, Ent. Div. Agr. Exper. Station, Cornell 
Univ., p. 267. 



31 

Adult. (Plate V., Fig. 1.) — The beetles arc small, from 6 mm. to 
7 mm. in length: Genera] color rusty red with black markings. The 
body is closely punctured and covered with fine short yellowish hairs. 
The head, a fusiform spot on the thorax, an oblong spol aeai the base 
of each \viii--eo\er. and an irregular larger hand crossing both wing- 
covers behind the middle, and the under side of the abdomen are black. 
The legs are brownish yellow. 

Notwithstanding the abundance of this species, comparatively little 
is yet known of its life history. Larvae placed in In-ceding cages by 
Professor Qomstock April 24 were found July 1 to have reached the bee- 
tle stage in earthen cells in the sod. Comstock and Slingerland were not 
able to say. however, whether the beetles soon emerged after this trans- 
formation or whether they hibernated in the earth. Our own records 
show so huge a number of collections of hibernating hectics of this species 
made from a variety of situations, that there can be little doubt that 
free hibernation is their habit. For example, November 1, 1883, they 
were taken under boards lying upon the ground. On the 7th of No- 
vember, 1884, they occurred with other hibernating insects at Normal, 
Illinois; and on the 14th and 15th of the same month they were col- 
ic, ted from driftwood along the Mississippi River near Quincy. De- 
cember :!. 1884, they were found in hibernation under leaves and rub- 
bish in strawberry fields, December 2, 9 and 16, 1889, tmVy were under 
boards on grass lands, and December 4 under leaves of dock and other 
plants in corn fields. December 23, 1891, and February 25, 1892, they 
were taken by us in the woods under leaves; and April 8, 1890, from 
roots of old corn and from under boards. March 31 and April "34, 1884, 
they were still in hibernation in strawberry fields, but by April 27, 
L892, specimens were taken on the wing at dusk. They are much the 
commonest in our collections made in May and July. 

Comstock found the larvae quite abundant in April in sod-land on 
the Cornell University farm. 

The larvae of eighteen small lots collected by office assistants in Illi- 
nois, divide readily into two well-distinguished sizes, and only two. 
Those of the smaller size, 6.2 mm. long, were taken March 26, June 5, 
11, 26, and 29, and in November, without date specified; and those of 
the larger size, averaging 8.8 mm. in length, were found May 19, 29, 
and 30, June 16, 17, and 20, July 8, August 18, and October 26. 

From these data it seems probable that this species emerges in 
summer and early fall, probably laying its eggs in part the same season, 
as indicated by my small larvae taken in November, and also, from timo- 
thy sod, the 26th of March ; that it hibernates in sheltered places and 
continues abundant until June of the following year, doubtless breeding 
meanwhile, as shown by the number of young larvae occurring in June; 
and that it lives two seasons in the earth before pupation — a supposi- 
tion necessary to account for the distinction in size noticeable in larvae 
collected together at various dates, practically throughout the entire year. 

It follows from the foregoing that late fall plowing, commended 
as a general defence against wireworm attack, would probably be sub- 
stantially without effect against this species. Breeding experiments 



32 

with respect to the habit of hibernation in the pupal chamber are, how- 
ever, needed to determine the value of this economic method for Bras- 

tcrins chgans. 

The Wheat Wirewobm. 

(Agriotes mancus, Say.) 

(Plate V., Fig. 4-6.) 

This larva, commonly known as the wheat wireworm, is injurious 
to corn as well as to small grain. It is a cylindrical pale brownish yei- 
low species, readily distinguished from any other wireworm (except 
another species of the same genus, doubtfully separate) by the smooth 
outlines of the last segment of the body, (which is slightly pointed at 
the tip), and especially by two conspicuous black circular pits upon 
the upper surface of this segment near its front border. 

It was first found by me in corn fields July 1, 1883, in a field neat 
Peru, Illinois, which had been broken up the preceding year from sod. 
Specimens collected here were devouring the roots of the corn and per- 
forating the stems just above the roots, the plants being at the time from 
eight to twelve inches high. The effect of this attack — especially of 
the perforation of the stems — was shown by the sudden withering of the 
infested stalks. About six per cent, of the corn in the field had already 
been killed in«this way. It was further obtained by us April 27, 1886, 
in an old corn field among specimens collected by following a plow. 

July 4, 1889, it was sent to us from Prophetstown, Illinois, with a 
report of serious injury to corn and potatoes, plants of which withered 
and died under the attack. A field of one hundred acres over which 
they seemed well distributed, was reclaimed swamp land, recently 
brought under cultivation. Finally, I found it near Sycamore, Illinois, 
on the 11th of July, 1889, in a field tiled and drained the year before 
and broken up in September from a marshy sod. In this field it had 
completely killed the corn in small patches, and notably crippled its 
growth in others. 

The larva has further occurred in our collections from pastures and 
meadows at Champaign. It is not nearly so abundant in Illinois as 
some other wireworms, only about one eighth of our office collections 
representing this species. In New York, however, it seems to be the 
commonest wireworm known, making ninety-one per cent, of some 
10,000 larvae sent to Professor Comstock, of Cornell University, for 
experimental uses. 

It has been published as a corn insect only in a brief note in"In- 
sect Life" (Vol. III., p. 246), by Mr. C. A. Hart, an assistant of this 
office, whose statement was based upon our breeding-cage work and col- 
lections. 

Its injuries to wheat, though doubtless occurring in Illinois, have 
not come to the notice of myself or my assistants. It has, however, been 
reported from wheat fields in Indiana by Mr. F. M. Webster,* infest- 

* Rep. U. S. Dept. Agr., 1887, p. 153. 



33 

ing there lands of various previous history. An older article by Mr. J. 
Pettit* gives a 1'nll acount of its attack on wheat. 

The length of time passed by this species in the Larva, or wireworm, 
state cannot be given with certainty. Mr. J. Pettit, of Ontario, who 
was the first to rear it from the larva to the adult, was of the opinion 
i hat the larval stale did not last longer than three years, f Messrs. 
Comstock and Slingerland, in their work on wireworms at the Cornell 
University Experiment Station, 1889-1891, from extensive and careful 
breeding-cage experiments — one at least of which continued through 
two years and two months — arrived at the same conclusion. They also 
ascertained that as the summer advanced the larvae became gradually 
less destructive, and that by November 1 (probably earlier in the fields) 
they eease feeding and go deeper into the ground, where they remain 
without food for five or six months. It is early in spring, when they be- 
gin to eat again after this long fast, that the greatest damage 's clone to 
crops. 

Larvae become full grown and pupate in July, in earthen cells. The 
change occurs a few days after these cells are formed, and pupae are 
most abundant about the middle of July. Adults may be found by the 
end of this month, and by about September 1 all the pupae have changed 
to beetles. For a few days after the change they are yellowish white in 
color, and nearly as tender as pupae. Before winter, however, they have 
become hard and normally colored. In Comstock' s experiments, the bee- 
tles passed the winter in their earthen cells, none coming to the surface 
the same fall unless their cells were injured. Adults thus disturbed did 
not form new cells, but worked their way to the surface ana soon died. 
In April the greater number of the beetles emerge from the earth, 
though we have taken them almost continuously from March '22 ^o the 
middle of July. They are most active in the evening or at night. 

Description. Larva, (Plate V., Fig. 5 and 6.) — "The newly hatched 
larvae must be very small, and, according to European writers, they 
grow very slowly. The smallest larvae of the wheat wireworm we have 
seen were about 4 mm. in length. All variations in size occur at the 
same time up to a full grown larva, which measures from 16 mm. to 19 
mm. The larva? are quite slender, cylindrical, somewhat flattened on 
the venter, sparsely hairy, and of a waxy yellow color, lighter at the 
sutures. The anal segment tapers gradually to a subacute brown point, 
and bears on the dorsal aspect, near the cephalic border, two large con- 
spicuous, brown, eye-like depressions resembling the breathing pores. 
By these, the wheat wireworm of any size may be readily separated from 
any other species which we have found infesting fields. "J 

Pupa. — "The pupa resembles the imago in many of its characters, 
being, however, about one fourth longer, and in the abdominal region 
more slender, the only differences of moment being the following: 

♦Can. Ent., Vol. IV. (1872), p. 3. 

t "Description of the "Wheat Wireworm." Can. Ent. Vol. IV. (1872), pp. 3-7. 
This article contains figures and descriptions of the larva and pupa by Dr. Horn, 
from specimens reared by Mt. Pettit. 

t Comstock and Slingerland, in Bull. 33 Ent. Div. Agr. Exper. Station, Cornell 
Univ., p. 252. 



34 

■•Thorax at each angle with a stout bristle-like appendage more 
slender towards the tip, about a sixteenth of an inch long. That at the 
anterior angle is supported on a small papilla, the posterior being pro- 
longed from the tip of the angle. Terminal abdominal segment above 
subquadrate, emarginate at tip, angles acute and divergent, beneath with 
a deep sinuous groove on each side and a median shallower groove. 

"Abdomen above and beneath of nine segments, the first very nar- 
row, distinctly visible above, beneath visible only at the sides; second 
slightly broader, beneath nearly entirely concealed. The remaining seg- 
ments are distinctly visible both above and beneath, the distal angles 
being slightly prominent, giving the sides of the abdomen a dentate ap- 
pearance." (Geo. H. Horx, Can. Ent. IV., 1872, p. 6.) 

•Imago. (Plate Y., Fig. -A.) — Eobust, color piceous to brown, elytra 
often paler, surface moderately pubescent. Head and thorax very con- 
vex, the mouth inferior, mandibles broad and chisel-shaped at tip; 
surface of head and thorax densely and coarsely punctate ; striag of elytra 
deep, punctate, interspaces nearly flat, rugose, and punctulate, antenna? 
and feet rufous. 

Length 7-9 mm. 

Agriotes pubescens, Mels. 

(Plate VI., Fig. 1.) 

This species, closely related to the foregoing, is not separable from 
it in the larval stage, and as the two occur in about equal abundance in 
corn fields and have a similar life history, they may best be treated — at 
least until more is known of them — as a single economic species. 

M&la/notus communis, Gryll. 

(Plate VI., Fig. 3-5.) 

This species is one of the most abundant of our click beetles, and 
the wireworm descended from it has been taken by us in about equal 
numbers with that of the following species (M. fissilis). The two to- 
gether make about twenty-eight per cent, of the wireworm collections of 
this office. The species is widely distributed, ranging at least from 
Nebraska to New Jersey and Canada. The wireworm of M. communis* 
though so abundant generally, has not been especially common in our 
collections from corn fields, only eight out of forty-five lots collected 
by office assistants having come to us from such situations. These were 
taken respectively June 30, 1883, from about the roots of corn near 
Milan; from corn fields at Champaign, May 25, 1885, and May 16, 
1886; from roots of corn after prairie sod at Mendota, July IT, 1881; 
from corn fields near Peoria, July 1, 1883, from sod corn at Mt. Pulaski, 
June 16, 1885; from corn at TJrbana. May 7, 1888; and from a corn 
field on the University premises at Urbana, Xovember 25, 1890. 

Life History. — The length of the larval period is not definitely 
known, but is not less than three years. According to the account of 
Comstock and Slingerland (with which our own breeding-cage results 
agree), pupation occurs during July, and about one month later the 
change to the adult state has taken place. The beetles under observation 

* The larva of M. fissilis, the species following, is ouite possibly included here. 



did not leave the cell in which they had undergone their transformations 
in the breeding cages, until the following spring, which would indicate 
thai they normally pass the winter in the ground. Harris says, how- 
ever, that they are I'.niiid under the hark of trees, where they pass the 
winter, having completed their transformation in the previous autumn. 
Dr. Fitch says that the beetles are most abundanl during the mouths of 
April, May, and June. Their numbers then diminish, and only a few- 
are to he round in August, hut they are again quite numerous in Sep- 
tember and the Eollowing mouths. 

In the collections of the office the hectics have heeil most abundant 
in April. Electric-light collections of Melanotus were made in May and 
June; and in November, December, and February, com munis has been 
taken in crevices of decaying logs and under hark in the woods. 

Description. — The larva' vary considerably in size at maturity, hut 
may he from 30 to 25 mm. long. 

"They are subcylindrical in form, nearly smooth, shining, and of 
a light brown color, with the head, thoracic and last segments consider- 
ably darker, and the venter and margins of the segments lighter in 
color. Body sparsely hairy, and each segment marked on the sides just 
dorsad of the spiracles with a linear impression. The cephalic border 
of the segments is slightly elevated and rendered distinct from the rest 
of the segment by a wavy dark border. Touching this border on each 
side of the dorsum of the segments, is a large, dark, elliptical, striated 
muscular impression. The caudal segment is much flattened, has no 
caudal notch, lint ends in a short, blunt, horny tubercle. On each side 
of this tubercle the margin is very obtusely notched, forming two wave- 
like projections. The dorsum of the segment is much roughened and 
marked by four linear impressions near the cephalic border, and a 
similar mesal depression on the dorsum near the caudal extremity. 

"The change to a pupa takes place during July. The mature larva 
forms an earthen cell similar and probably made in a similar manner 
to the cell of the wheat wireworm. This cell is about three fourths of 
an inch in length and three eighths of an inch wide. Soon after the 
cell is finished the skin of the larva opens at the sutures on the top of 
the head and along the median line on the dorsum of the following three 
or four segments. The white and tender pupa then works itself out, 
leaving the cast larval skin crowded into one end of the cell. The wing- 
pads, legs, and antenna? of the pupa are folded closely on the breast. 
In other respects it resembles the beetle, but is nearly one fourth longer, 
and the nine segments of the abdomen are distinctly visible. It is much 
larger than the pupa of the wheat wireworm, and in addition to the long 
sharp bristle at each angle of the thorax it has two similar shorter ones, 
one each side of the mesal linear depression near the caudal border of 
the thorax." 

"The change to a beetle takes place in about one month. The 
rather slender, glossy, dark brown beetle varies from 11 mm. to 15 mm. 
in length, and its body is closely punctured and clothed with fine, short, 
incumbent grayish hairs. The wing-covers are striated by deep oblong 
punctures, the intervening spaces flat and minutely punctured. The 
mouth parts are on the anterior portion of the head, and the front is 
slightly flattened but distinctly margined back of the labrum. The an- 



36 

tennse are reddish brown and serrate. A smooth, shallow, impressed line 
extends along the mesal portion of the thorax. The tarsi are not lobed 
beneath and the claws are pectinate."— Comstock & Slingerland. 

Melanotus fissilis, Say. 

(Plate VI., Fig. 2.) 

This species is, according to Le Conte, abundant throughout the 
Middle and Southern States, and it also extends northward into Canada. 
The larvae and beetles are associated with those of M. communis through- 
out Illinois, but in the southern part of the State this is the more 
abundant of the two. 

The larva has not been separated by us from that of M. communis, 
and the two are quite possibly indistinguishable. 

The beetle is from 12 mm. to 15 mm. in length, a dark reddish 
brown in color, with the body closely punctured and covered with fine, 
short, pale yellowish or grayish hairs. The wing-covers are striated with 
deep punctures and the flat intervening spaces are minutely punctured. 
The thorax in fissilis is without the smooth median longitudinal impressed 
line found in communis, otherwise it is difficult to distinguish these species. 

Life History. — The life history of this species is probably parallel 
with that of M. communis, pupa?, being found by us July 12, 1886, and 
August 12, 1889, as in that species. A pupa introduced accidentally, in 
blue-grass sod, into a cutworm cage in 1889, probably had its cell broken 
in moving the sod, and August 20 it was found lying on the surface. 
August 22 the beetle cast off the pupa skin and appeared to be none the 
worse for its strange experience. Larvae that had already formed cells 
May 26, 1890, in the breeding cage, about six inches below the surface, 
had pupated July 26. From a stock-cage of wireworms collected at 
various times for experimental use during the spring of 1889, we ob- 
tained September 21 several specimens of this species, with hardened 
crusts and fully developed color, as if their final transformations had 
been completed some little time before. They were still in their pupal 
cells, where they would probably have passed the winter if they had 
not been disturbed. 

Our collections of imagos have been made at substantially the same 
times as those of communis. In November, December, and February, 
numbers of adults were found in crevices of old logs, sometimes as many 
as a dozen to thirty or more within a few square inches. 

Melanotus infaustus, Lee. 

A single specimen of this beetle was bred in 1889 from a lot of 
larva? kept in a stock cage and fed upon corn, the others giving us M. 
fissilis. All were collected in a corn field near Champaign, and after 
being placed in the breeding cage were not disturbed until September 
21, 1889. They were then found to be well-colored adults lying snugly 
in the pupal cells, and apparently prepared to pass the winter there. 

The adult is 11.5 mm. in length, of a dark brownish color, rather 
slender, and covered with grayish hairs. The thorax is longer than 
wide, with straight, diverging sides, and the posterior angles have only 
a single carina. It is rounded in front, and is very sparsely punctate. 



The form of the thorax clearly distinguishes this species from the 
others attacking corn. The legs and antennas are chestnut-red. 

'Tin: COEN WlREWORM. 

(Melanotics cribulosus, Lee.) 

(Plate VI., Fig. 6-8; and Plate VII., Pig. I.) 

This is without doubt by far the commonest wireworm in corn 
fields in Illinois. Larvae referable to it make not less than one third 
of the wireworm collections of this office, and fully half of these were 
taken in corn fields at dates from April 27 to June 28, that is to say 
during the time when wireworm injury to corn is generally commonest 
and most serious. On the other hand, the adult is far outnumbered by 
M. communis in miscellaneous collections, being, indeed, rather rare 
with us except among insects obtained from corn fields or bred from 
larvae infesting corn. Le Conte found the species in Nebraska, and 
Smith's Catalogue of the Insects of New Jersey credits it to that state. 

Little has been added to our knowledge of this species since I pub- 
lished in 1880 a brief account of its life history in my Miscellaneous 
Essays on Economic Entomology (p. 17). The statements of that article 
were based chiefly upon observations made in 1885 in a field of corn in 
Champaign county which had lain in pasture for many years before. 

The injury to which corn is liable when the ground is infested by 
this species was well illustrated by the condition of this field, where I 
estimated that wireworms averaged three to a hill for the entire area, 
the number ranging from two to six or eight. Only about one hill in 
fifty was found free from them in the higher, more sandy, parts of the 
field, although on the lowest ground there were no wireworms at all in 
several hills examined. They had attacked only the kernels as yet, but 
would later, of course, have eaten the roots and burrowed the under- 
ground portions of the stalk. All the wireworms in this field were 
concentrated in the hills of corn, not a single one being found during 
protracted search made elsewhere. Even the few remaining tufts of sod 
of the preceding year were -free from them where the hills around were 
badly infested. The ground had been in corn the year before, and had 
then been considerably damaged, but not nearly as much so as at the 
time of my visit. It had, however, been replanted about June 1 (1884), 
and the owner was plowing up the first planting May 25, 1885, with a 
view to planting again. 

The wireworms taken from this field were easily assorted in two 
lots, and only two, according to size. Placed in breeding cages May 
25, they were still living as larvae June 13 and July 12. By August 3 
pupation had begun, the pupae being enclosed in elongate cells in the 
earth, and on the 22d pupae were again found, but no imagos, while 
September 12 pupa?, recently transformed imagos, and others of a color 
and consistency to indicate that they had changed at least a few days 
•previously were found still in the earth. None of the beetles came out 
of the earth in the cage during early fall or winter, but February 17, 
1886. all were found dead in their pupal cells, badly infested by mites. 
The larvae of the smaller size were not bred in this experiment, but only 
those seemingly full grown. All the specimens reared were cribulosus, 



except a single com munis, which may not impossibly have been intro- 
duced with the sod. The earth in the breeding cages was mixed with 
soaked corn kept covered with fresh sod. 

A similar but smaller experiment was made the following year, with 
a like result, wireworms placed in a breeding cage in May yielding the 
adult of this species by September 17. 

From these experiments it is evident that the larval life of cribit- 
losus, and clearly of communis also, is completed during the latter part 
of the summer, and that the transformation to the imago begins in early 
autumn. It is probable that the imagos emerging pass the winter in 
their pupal cells, although the death of our specimens in the earth 
makes the evidence on this point incomplete. 

The hibernation of this species above ground anywhere outside its 
pupal chamber has not been positively ascertained by us. The only col- 
lections made from the office which could possibly bear this interpreta- 
tion are five obtained in April from the 8th to the 28th of the month. 
Three of these were from ground being plowed, and both the! other 
specimens came from corn fields — one from about the roots of old corn 
of the preceding year. 

Description. Larva. (Plate VI., Fig. 6-8.) — Length about 20 
mm., width 2 mm. Subcylindrical, slightly depressed, yellow-castaneous, 
extremities darker, surface glabrous and shining, minutely and very 
sparsely punctate. 

Head flattened- clypeus with a rather sharp black tooth at middle, 
and a shorter tooth each side. Exterior to these, the front margin bears 
a brush of long, golden yellow hair. Four sulci extend back from the 
front margin, the outer pair ending in a setigerous puncture. The 
posterior clypeal prolongation widens slightly behind the constriction 
and usually tapers a little posteriorly, but does not become narrower 
than at the constriction. Labrum invisible. Mandibles black, toothed 
internally. Maxilla? and labium as usual in wireworms, the palpi short 
and stout. Antenna? short, the penultimate joint obtusely toothed be- 
neath, the last joint hemispherical, whitish. 

First thoracic segment about as long as the other two combined. 
Abdominal segments about two thirds as long as the prothoracic, except 
the first, which is shorter, and the last, which is nearly twice as long as 
the one preceding. Each segment bears an elevated border in front, 
limited by a sharp darker edge posteriorly, which is obsolete at the 
middle on the thoracic and first abdominal segments. This edge curves 
suddenly backward in front of the spiracles. These are oblong ovate, 
not far from the anterior margins of the segments, one on each ab- 
dominal segment except the last, and the thoracic pair on the mesotho- 
rax below the lateral margin. Above the spiracles, close to the elevated 
border, is a transverse longitudinally striated oval muscular impression, 
and between them and the spiracles originates an impressed line which 
extends backwards partially across the segment. The stria? of the mus- 
cular impressions are light colored, and they are separated by dark 
brown flat intervals. On the middle segments of the body there are 
usually five stria? in each impression, sometimes fewer, and in one speci- 
men none. On the terminal segments the number may reach ten or 
twelve ; and on the prothorax there are usually more than five. The legs 



39 

are stout, and armed with browc spines. The last segment is charac- 
teristic of the species. Anteriorly it is quite e<>nve\, and marked with 
four Longitudinal Qearly parallel impressed lines, the inner pair diverg- 
ing anteriorly; posteriorly it is flattened a little, especially at the tip. 

The surface is covered, as usual in Melanotus, with small tubercles, 
more numerous near the tip, and is also rather coarsely punctate over 
the posterior two thirds, more closely near the tip. In M. communis 
the punctures are finer, sparser, and much less conspicuous. At the tip 
of the segmenl is a short, feebly elevated margin, ending on either side 
in an angle or blunt tooth, and hearing a third angle or tooth at middle; 
the outline between the teeth often scarcely concave. The sides of the 
segment are rounded, not evidently margined or angulate. 

Imago. (Plate VII., Fig. 1). — Length 9-11 mm. Pubescent; 
color brownish fuscous, lighter than in communis, and tapering less 
posteriorly. The front is not concave or margined. The thorax above 
coarsely and rather densely punctate, shining; sides nearly straight in 
male, rounded in female ; posterior angles unicarinate. Claws pectinate 
as usual in Melanotus. 

Asaplies decoloratus, Say. 

(Plate VII., Fig. 2-4.) 

This widely distributed species, occurring through all the Northern 
States east of the Mississippi Kiver, is fairly abundant in our collec- 
tions, nearly one third of them coming from corn fields. Otherwise the 
larva' have been collected in meadows and pastures and freshly plowed 
sod, from oats fields (twice) and clover, and once from woodlands. 

Of the frequency and amount of its injuries to corn, as compared 
with other species infesting that crop, we have no very precise informa- 
tion. The general drift of our observations is, however, to the effect 
that it is of little significance as a corn insect ; a conclusion of some 
interest, since its life history differs from that of the other species in a 
way to render it less subject to destruction by fall plowing — almost the 
only preventive measure hitherto found practically useful for wire- 
worms. Indeed, the early date at which larval activity ceases, makes it 
unlikely that injuries by this species will be as serious as those whose 
period of pupation comes later in the season. 

Life History. — Shortened larvae enclosed in oblong oval cavities 
were turned out by the plow in a corn field in Urbana April 20, 1886. 
They were placed in a breeding cage, and by May 15 one of them had 
pupated on the surface of the earth. June 7 one beetle of the lot emerged, 
and another partially escaped from its pupal skin, but died before com- 
pleting the transformation. In other breeding cages larva' were found 
to have pupated May 16 and June 13, 1886, and a beetle was obtained 
from the earlier one on June 2. On 'May 16, 1887, a pupa was turned 
out by the plow in a corn field, and the beetle from it appeared May 25. 
In a cage containing larvae taken in a clover field, both larva? and pupae 
were found July IS), 1887. Again, larva 1 kept in an insecure cage out- 
doors had formed cells as late as June 17, 1890, but they had not pu- 
pated on July 1. Subsequently, when the cage was examined, all had 
escaped. 

—4 E 



40 

The experience of Conistock and Slingerland was to the same gen- 
eral effect, except that preparations for pupation did not begin with 
them until the latter part of May or the first of June. Adults had 
emerged, however, from their pupal cells by June 27, in about six weeks 
after the larvae had been placed in their breeding cages. With us, it 
will be noticed, preparations for pupation began April 20, the first 
pupae were found May 15 and 16, and the beetles appeared as early as 
May 25. The pupal stage was of about three weeks duration. 

Description. Larva. (Plate VII., Fig. 3 and 4.) — "Subcylindri- 
cal in form ; considerably flattened'; dorsum slightly more convex ; and 
lateral fold prominent. Length, when full grown, 20 mm. to 25 mm. 
Color dark waxy yellow; mandibles and cephalic margin of head black 
shading gradually into the dark brown color of the head. Head flatten- 
ed, and with long brown hairs arising from the pits on the sides. The 
clypeus with the caudal portion fusiform, the cephalic part of this por- 
tion narrower than the caudal part; cephalic margin of clypeus with a 
large, prominent, three-toothed. lobe on median line; the mesal tooth of 
this lobe is larger and longer than the others; on some specimens these 
teeth are mure or less worn off. Labrum apparently wanting, being en- 
tirely within the cavity of the mouth. The mandibles are large, arcuate, 
and bear a short curved median tooth on the mesal side. The maxilla? 
have the cardo strongly bilobed; the stipes very slightly diminish in 
width toward the proximal end, which is truncate. The sides of the 
gula are nearly parallel, this part being but slightly narrowed towards 
its base; the base is rounded, with one long hair arising from a deep 
excavation near each lateral angle. Prothoracic segment subquadrate 
and nearly as long as the other two thoracic segments. The remaining 
segments of the body of nearly uniform length, slightly constricted at 
the sutures, and almost twice as wide as long. The caudal segment is 
considerably flattened, and has a large oval caudal notch formed by 
two rather long flattened projections, each of which curves slightly dor- 
sad and terminates in two short, .blunt, horny diverging tubercles; the 
two inner tubercles project dorso-mesad, with a small hair-bearing 
tubercle arising from the lateral aspect; the outer tubercles project 
nearly directly dorsad. The dorsum of the segment is bounded by a nar- 
row ridge which on the sides of the segment bears four short, distinct, 
blunt, horny tubercles, the more caudal one being considerably larger. 
The area bounded by this ridge is convex cephalad, slightly roughened. 
bears no hairs, and is marked by a deep, roughened, linear depression 
on each side and a short mesal linear impression extending from the 
middle of the area to the caudal notch; ventral portion of the seg- 
ment slightly wrinkled; the semicircular fold around the anal proleg 
extends upon the base of the leg in the form of a thin finely striated 
margin ; the distal margins of the joints of the leg are similarly striated 
The prosternnm is triangular, and acutely wedge-shaped caudad. The 
thoracic legs are short and stout. ; each joint armed with short brown 
spines. Spiracles large, elongate oval, brown; there is a single thoracic 
pair situated on the second thoracic segment on the inflexed portion just 
in front of the coxes ; there are eight abdominal pairs, each situated near 
the cephalic border of the segment. Surface of the body shining, 



41 

nearly smooth on the thoracic segments and on the venter; the dorsum 
of the abdominal segments is marked with numerous shallow trans- 
verse notches, and a slight dark ridge which crosses the segment near the 
cephalic border, then curves suddenly, extends obliquely caudo-ven- 
trad on each side and nearly meets the faint impressed line extending 
across the segment. The caudal and cephalic margins of the first tho- 
racic segment, and the caudal margin of the other segments, except the 
first and last, are marked by numerous line longitudinal stria?. A linear 
mesal depression ending abruptly near the caudal border of each seg- 
ment, extends along the dorsum. Body sparsely clothed with long yel- 
lowish brown hairs; a row of from 18 to 22 hairs extends around the 
body from one subdorsal line to the other near the caudal border of 
each segment except the head and last segment ; two similar hairs arise 
near the cephalic margin of the segments, one dorsad and the other 
ventrad of each spiracle; the lateral and caudal tubercles on the anal 
segment have one or two hairs arising from their sides, and other hairs 
arise from the proleg and from small tubercles on the venter of the seg- 
ment." — COMSTOCK & SLINGERLAND. 

Imago. (Plate VII., Fig. 2.) — "Piceous black, shining, surface 
often with aeneous tinge, elytra often pale, legs pale rufous; surface 
sparsely clothed with grayish pubescence. Thorax moderately, not 
densely, punctured, hind angles divergent, carinate, the carina diverg- 
ing from the margin; flanks moderately densely punctured in front, a 
large smooth space posteriorly. Elytra moderately deeply striate, stria? 
punctured, intervals convex and punctulate. The prosternal mucro is 
horizontal, the mesosternum is however not prominent. Length 9-15 
mm."— Geo. H. Horn. (Trans. Am. Ent, Soc. VIII., p. 73.) 

The female differs from the male in .having the thorax shorter, its 
disk more convex and punctured, the sides more arcuate, and the gen- 
eral form stouter and more convex 

NATURAL ENEMIES OF WIRE WORMS. 

A single parasitic fly has been bred by us from a wireworm, which 
because of its condition when found, could be only doubtfully referred 
to Melwnotus fissilis. Comstock and Slingerland frequently found 
larva? killed in their breeding cages by a fungus determined by Profes- 
sor Roland Thaxter as probably Metarrhiziux anixopl'm Larvae killed 
by this disease have the body filled by the growth of the fungus, and 
assume a woody appearance. An Asaphes larva turned out by the plow 
at Champaign May 10, 1886, was infested by a parasitic fungus of an- 
other genus, very much like Cordyceps. 

In my work on the food of birds,* I found that some seventeen 
species eat to some extent "click beetles," or their larva?, the wireworms. 
These insects constitute about two per cent, of the food of five species 
of the thrush family — the robin and the brown, the hermit, the wood, 
and the Alice, thrushes. The examination of the food of these birds 
continued throughout the year, and the proportionate amount of these 
beetles eaten was found to be greatest during the months when they 

* Bull. 111. State Lab. Nat. Hist., Vols. I and II. 



42 

were most numerous; but even then the quantity destroyed was scarce- 
ly sufficient to affect materially their average numbers. Mr. E. V. Wil- 
cox,* while studying the food of the rohiu. at the Ohio Agricultural Ex- 
periment Station, found in the stomachs of twenty-sewn of these birds, 
shot in April and May, Elaterida 3 amounting to three and one half per 
cent, of their food. Of the remaining species of birds known to eat 
them, none take enough to make more than a fraction of one per cent, 
of their food, except, perhaps, the crow. Dr. Fitch says that "wire- 
worms and their progenitors, the snapping beetles, constitute the favorite 
food and principal sustenance of these birds [crows] ."f 

PREVENTION AND REMEDY. 

Probably no class of agricultural insects has had prescribed for it 
a longer list of artificial remedies than the wireworms, and certainly no 
such list has been of less practical value. After many generations of 
experience with their work in this country and in Europe their injuries 
continue at present practically unchecked by any treatment consistent 
with the methods of American agriculture. 

Even poisons of the most deadly sort applied to corn previous to 
planting, or to food lures distributed through the ground for the pur- 
pose of drawing off the attention of these insects from corn, have proven 
almost entirely valueless, both in my experience and in the more elab- 
orate trials made by Comstock and Slingerland in Xew York. Late fall 
plowing, breaking open the pupal chambers within which the recently 
transformed adults pass the winter, will probably have the effect to di- 
minish generally the number of these beetles during the following year. 
Comstock and Slingerland have also ascertained that the adult beetles 
are susceptible to certain poisons judiciously distributed with certan at- 
tractive kinds of food; and I have to suggest a systematic rotation in- 
tended to interpose between grass and corn a crop not vulnerable to the 
wireworm. Otherwise we are substantially without a hint of any means 
of diminishing the ravages of these insects other than the time-honored 
resource of the corn farmer, namely, late planting of his corn the second 
year after sod, and late replanting if the first planting is destroyed. In 
the latter case it is well to plant between the rows, allowing the first 
corn to stand as long as is consistent with a proper cultivation of the field. 
All the wireworms being at the time concentrated in the old hills of corn, 
if these be destroyed when the field is. planted the second time, the wire- 
worms still active in the earth are forced to attack the freshly planted 
kernels as their only food resource. 

The first experiments with poisons for the wireworms of which we 
have definite record, were made at my office in 1885, and reported briefly 
in my "Miscellaneous Essays on Economic Entomology" (p. 18), printed 
the following year. 

Later, in May, 1888, we fed thirty-seven wireworms on corn soaked 
for seven days in a mixture of water and Paris green. The corn was 
covered with a coating of the green poison, and was eaten freely by some 
of the worms without killing them. Twelve wireworms fed on corn 



* Bull. Ohio Agr. Exper. Station, No. 43, (1892), p. 127. 

t Eleventh Rep. (Trans. N. Y. State Agr. Soc, (1866), p. 542. 



43 

soaked in Fowler's solution diluted with an equal quantity of water were 
not affected, although a portion of the corn was eaten. Twelve others 
fed on corn soaked in an alcoholic solution of arsenic, were nol injured 
by the poison, though feeding freely on the corn. Experiments in June 
and July, when wireworms were led on com soaked in a solution of ar- 
seide in boiling water, were less satisfactory because the larvae were so 
near pupation that they ate little or none, pupa] cells being formed five 
days after the experiment began. Corn soaked in a solution of strych- 
nine — four grains to a half pin! of water — over night, and fed to seven 
wireworms June S. 1888, had not affected them \>y duly 5, although 
the corn was slightly eaten. Twelve worms supplied with corn soaked 
twenty-four hours in an alcoholic solution of corrosive sublimate June 
27, 1888, did not eat the corn. 

A repetition of these experiments in June and July, 1891, by a dif- 
ferent assistant and under somewhat different conditions, gave sub- 
stantially the same results. June 7, 1891, corn was soaked in a saturat- 
ed solution of potassium cyanide and fed to three wireworms. July 3 
one grain of corn was slightly eaten, and July 10 one grain was badly 
eaten and one worm missing — probably eaten by mice that had obtained 
access to the cage. July 20 several grains were badly eaten; July 27 
the remaining two worms were active, but the corn was untouched; and 
the experiment ended without effect. 

In many of the experiments, particularly when alcoholic solutions 
were used, or where the corn was soaked for a considerable length of 
time in arsenical solutions, it failed entirely to germinate; while in 
experiments where the grain was simply wet and rolled in the arsenites, 
or soaked for only a few hours, it grew almost as freely as did untreated 
corn in check lots. 

These experiments with the arsenical poisons and strychnine agree 
substantially with those of Messrs. Comstock and Slingerland, published 
in November, 1891, and show that it is not practicable to protect the 
corn by means of them, even were it possible to use them without re- 
tarding or preventing the germinating of the seed. 

Coating the kernels with tar and soaking them in a solution of salt, 
a solution of copperas, a solution of chloride of lime and copperas, in 
spirits of turpentine, and in kerosene oil, have been tried by Comstock 
and Slingerland without encouraging results. 

Applications of kerosene emulsion and pure kerosene made to the 
worms in the earth were found by me in f885 practically ineffective, any 
strength sufficient to kill the larvae killing vegetation also. Similar re- 
sults were obtained by Comstock and Slingerland, who, after using crude 
petroleum, an emulsion of the same, and a common kerosene emulsion, 
concluded that the last is more promising than the others, but that it 
cannot he profitably applied on a large scale. Experiments made by 
them show also that even a clean fallow for an entire season will not 
starve out the worms; that neither buckwheat, mustard, nor rape crops 
— frequently recommended to clear the earth of wireworms — will ac- 
complish the desired result ; and that salt applied at the rate of 1,600 
pounds to the acre — a heavy dressing — neither drives the wireworms 



44 

deeper into the soil nor causes them to migrate to any appreciable dis- 
tance ; that kainit used as a fertilizer, even in very large quantities, had 
little if any effect on the wireworms;* that muriate of potash — four to 
six tons to the acre (an excessive amount) — is but slightly effective; 
that lime at the rate of even two hundred bushels per acre does not in- 
jure wireworms; that chloride of lime must be used in impracticable 
quantity to produce any marked effect; and that gas-lime, although capa- 
ble of destroying the wireworms, must be applied in such great quanti- 
ties that its use is impracticable on large areas. Bisulphide of carbon 
poured into a hole in the earth near the infested hill destroys the wire- 
worms, but at an excessive cost. 

The most promising remedy for wireworms, in my judgment, is 
one which has unfortunately not been experimentally tested, but which 
is, nevertheless, precisely based upon our knowledge of the life history, 
food, and habits of these insects. It consists of a rotation in which 
clover follows always upon grass and is itself followed by corn. Ac- 
cm ding to this plan pastures and meadows of grass might lie unchanged 
for several years, being plowed, when broken up, in late summer or 
early fall and sown to clover in the spring — either with oats, or on win- 
ter wheat or rye sown the fall before. The clover should be allowed to 
stand a second year, and might then be followed with corn with positive 
assurance that the wireworms originally in the sod would by that time 
have entirely disappeared. From the regular rotation for grain lands, 
grass would thus be excluded. In such a rotation corn might be fol- 
lowed by small grain, this by clover, and this by corn. While the wire- 
worms might produce some visible effect on the small grain the first 
year after grass, this would usually be much less serious, at any rate, 
than the damage to corn. 

The general entomological effect of some such management could 
not fail to be beneficial, since it would apply to cutworms and white 
grubs as well as to the wireworms now under discussion. The system of 
rotation now common in Central Illinois is, indeed, seriously defective in 
the fact that the plants composing it — Indian corn, small grains, and 
grasses — are all of the same botanical family and consequently subject 
in large measure to the same enemies. Any variation of this system 
which will introduce as a regular link in the chain a crop belonging to 
some other and widely different family of plants, will serve the genial 
purpose of that here proposed. 

* These results are inconsistent with those reported by Prof. J. B. Smith in the 
12th Ann. Rep. N. J. Agr. Exper. Station (for the year 1891), p. 412. Here Professor 
Voorhees, Chemist of the Station, is said to have applied kainit and muriate of 
potash separately to two sections of a fourteen-acre piece of corn on ground always 
badly infested by wireworms and cutworms, leaving a strip between these sections 
without treatment. Care was taken that the sections should be similar with respect 
to quality of land, situation, etc. As a consequence, the kainit section was reported 
as almost entirely exempt from injury by insects, the muriate section as but little 
infested, and the intermediate strip as almost destroyed. It is evident from the 
context that this experiment had been made some years before, apparently not under 
the inspection of an entomologist. 



45 



B. Injuries to the roots. 

Injury to the roots of corn in spring and early summer may be 
indicated to the close observer by the aspect of the growing crop. If 
the corn fails to appear in spring, the difficulty may not be due to poor 
seed or to injuries to the kernel, but may be caused by an early insect 
attack upon the young roots, which may even kill the plant outright 
before the sprout lias broken ground. The root louse of the corn and 
the wireworms are most likely to be concerned in this form of injury. 

Later in the season, when the plant is a few inches high, the uneven 
growth of the corn will often attract attention, patches here and there 
advancing slowly in comparison with parts of the field adjacent, and 
in a way not to be accounted for by differences of soil. In such cases, 
white grubs, wireworms, corn root worms., or plant lice should be sought 
for. Combined with this uneven growth, or possibly in times of drouth 
without it, the farmer may notice yellow patches in his field, the color 
being most pronounced upon the lower leaves. The root louse of the 
corn will be found responsible in most cases for this partial discoloration, 
but any of the species just mentioned may produce a similar effect,* 
or it may be caused on the lower part of the stalk by the chinch bug. 

An especially significant symptom of more or less serious mischief 
is the presence in the field of numerous burrows of ants, commonly 
placed in or immediately near the hills of corn, and most conspicuous 
shortly after rains. This invariably indicates the presence of root lice 
in the field, although if the corn be small a careful search .may fail to 
detect them at the time. The nature of the association between the ants 
and the root lice is such that the former prepare the way for the latter 
early in the season by sinking their burrows among the corn roots, thus 
giving the lice access to them. 

If at about the time the ear is beginning to form, and from that 
time onward, the stalks of corn are easily prostrated by wind and rain, 
and do not readily rise again, it will commonly be found that the hold 
of the plant upon the earth is abnormally slight, so that the hill may be 
pulled up too easily. This condition of the plant is due to a loss of 
roots, usually to be attributed to one of the corn root worms, or, more 

* A condition of the corn very similar to that just described is not due to insect 
attack at all, but to a bacterial disease of the roots known as the com root blight, 
fully described by Prof. T. J. Burrill in Bulletin No. 6 of the Illinois Agricultural 
Experiment Station (August. 1889). In this disease the corn stops growing in 
patches, becoming yellow and usually slender, and sometimes dying while young. 
The yellow color is most pronounced upon the lowest leaves. On pulling up the 
plant, the oldest and the lowest roots are seen to be injured and usually dead, the 
bottom part of the stalk to which these roots are attached being similarly affected. 
If split through the middle, the inner tissue of this lower part is seen to be of a 
uniform darker color, and a slight discoloration, becoming less and less pronounced 
above, appears in the next succeeding joints, while the parts between them are 
seemingly healthy. On the surface, when carefully cleared of dirt, brownish cor- 
roded spots may be found, sometimes covered with a firm gelatinous material. 



46 

rarely, to the white grubs. Sometimes, however, a similar appearance is 
given late in the season to a field infested by the chinch bug, which by 
abstracting sap from about the base of the stalk just beneath the surface 
of the ground will often prevent the shooting forth of the so-called 
"brace-roots. "' which serve to anchor the top-heavy stalk more firmly in 
the earth. 



SYNOPSIS OF IXJUEIES TO THE BOOTS, AND OBDEB OF 
DISCUSSION. 

1. Eoots deadened, hardened, or dwarfed, without apparent loss of 
substance. Page 18. 

a. Small brown or yellowish ants abundant in the hills, and 

bluish green or whitish root lice on the larger roots. 

Page 48. 
Plant Lice and Mealy Bugs : Page 48. 

Aphis maidiradicis (The Corn Eoot Aphis). (Plate 

VIE, Fig. 5 and 6; and Plate YIIL, Fig. 1-5.) 

Page 50. 
Schizoneura [jcuiicola (The Grass Eoot Louse). (Plate 

YIIL, Fig. 6- and Plate IX., Fig. 1.) Page 75. 
Trama erigeronensis. (Plate IX., Fig. 2.) Page 82. 
Forda occulentalis. (Plate IX., Fig. 3.) Page 84. 
Tychea brevicomis. (Plate IX., Fig. 4.) Page 86. 
Geoica squamosa. (Plate IX., Fig. 5 and 6; and Plate 

X., Fig. 1, 2, and 3.) Page 87. 
Rhizobius spicatus (The Woolly Grass Eoot Louse). 

(Plate X., Fig. 4.) Page 92. 
Dactylopius sorghiellus (The Corn Mealy Bug). (Plate 

X., Fig. 7 and 8.) Page 94. 
Ants: Pages 5? and 72. 

Sulrnuji.sis debilis. (Plate II. , Fig. 2.) Page 57. 
Myrmica scabrinodis lobicornis. (Plate I. and Plate II., 

Fig. 1.) Page 57. 
Lasius niger. Page 72. 
Lasius niger alienus. (Plate X., Fig. 5 and 6; and 

Plate XL, Fig. 1.) Page 72. 
Lasius inter jeotus. Page 57. 

Formica schaufussi. (Plate XL, Fig. 2.) Page 57. 
Formica fusca. Page 57. 

b. No notable number of insects present. The lowest roots dead ; 

surface of underground part of stalk with brownish 
corroded spots, interior of this part darker, at least at 
the joints, while the spaces between may be seemingly 
healthy. (Boot blight of corn, a bacterial disease; not 
entomological.) Page 45. 



47 

2. Hoots evidently injured or destroyed by perforations, gnawing, bur- 
rowing, decay, or other loss of substance. Page 96. 

a. Roots eaten away, not burrowed or perforated, and without 

rotten or withered tips; tap-root commonly gone or 

decayed. White grubs in soil among or beneath the 

roots. Page 96. 
White Grubs. Page 96. 
Lachnosterna rugosd. (Plate XIL, Fig. 1-.'!.) Page 122. 
Lachnostema fusca. (Plate XII., Fig. -L and 5.) Page 

121. 
Lachnosterna inv-ersa. (Plate XII., Fig. 5.) Page 121. 
I. m •hnosterna hirticula. ( Plate XII., Fig. 3.) Page 122. 
Lachnosterna ijibbosa. (Plate XII., Fig. 6 and 7.) Page 

122. 
Cyclocephala immaculata. (Plate XII., Fig. 8; and 

Plate XIII., Fig. 1 and 2.) Page 121. 
AUorhina nitida (The Green -June Beetle). (Plate XIII., 

Fig. 7.) Page 127. 
Prionm laticollis. (Plate XIII., Fig. 4.) Page 128. 
Priouus imhricornis. (Plate XIII., Fig. 3.) Page 128. 

b. Roots penetrated, perforated, irregularly bnrrowed, and more 

or less eaten off and eaten up. Underground parts of 
stalk also usually similarly injured. Page 129. 
Wireworms in soil among the roots. Page 2-1. 
Wireworins. Pages 24, 41, 42. 

Gardiophorus sp. (Plate IV., Fig. G.) Page 28. 
Drasterms elegans. (Plate V., Fig. 1-3.) Page 29. 
Agriotes mcmcus (The Wheat Wireworm). Plate V., 

Fig. 4-6.) Page 32. 
Agriotes pubjeseetis. (Plate VI., Fig. 1.) Page 34. 
Melanotus cam munis. (Plate VI., Fig. 3-5.) Page 34. 
Melanotics fisstiis. (Plate VI., Fig. 2.) Page 36. 
Melanotus infaustus. Page 36. 
Melanotus cribulosus (The Corn Wireworm). Plate 

VI., Fig. 6-8; and Plate VII., Fig. 1.) Page 37. 
Asaphes decoloraius. (Plate VII., Fig. 2-4.) Page 39. 
Small, slender, soft-bodied, yellowish white grubs in the 
roots and earth. Page 129. 
Diabrotica 12-punctata (The Southern Corn Root 
Worm). (Plate XIV., Fig. 1-5.) Page 129. 

c. Roots visibly penetrated and perforated scarcely at all ; some- 

times decayed at tips, but not eaten away. Principal 
injury interior, in form of minute burrows which are 
commonly longitudinal, discoverable on peeling or 
splitting the root, the burrows sometimes containing 
minute slender white six-legged larvae, with brown 
head and neck and brown natch on last segment. Page 
135. 



48 

Diabrotica longicomis (The Northern Corn Root Worm). 
(Plate XIV., Fig. 6-8; and Plate XV., Fig. 1-8.) 
Page 135. 

Detailed Discussion of Injuries to the Eoots. 

1. Some of the routs deadened, hardened, or dwarfed, without loss of 
substance. 
a. Small brown or yellowish ants abundant in the hills, and very 
small, bluish green or whitish, oval, thick-bodied root 
lice on the larger roots. 

PLANT LICE AND MEALY BUGS. 
(Aphidid.e and Cocctd^e) 

Associated with ants in hills of corn, the observer may find any one 
or more of eight species of minute, soft, thick-bodied, six-legged insects, 
sometimes winged, but usually without wings, and always of very slug- 
gish habit and slight power of locomotion. When exposed, they may 
show little or no signs of disturbance, but if shaken off the roots into 
which their stout jointed beaks are thrust, they will probably crawl 
slowly and clumsily about, making movements almost too sluggish and 
aimless to look like efforts to escape. The ants which have nested in 
the hiM will, however, commonly seize these little insects in their man- 
dibles and hurry away with them into concealment. 

By far the greater part of those answering to the above description 
to be found in the corn field, will usually be plant lice (aphides) ; and 
will mostly belong, in fact, to a single species, the corn root aphis; but 
a few may be "mealy bugs" (genus Dactvlopius, family Coccida?), rec- 
ognizable as such by their general resemblance to the kinds of "mealy 
bugs" common in greenhouses. They may be readily distinguished 
from the plant lice by their thicker, clumsier bodies, and by the almost 
rudimentary size of their legs and antennas. They are always covered 
with a mealy or powdery excretion of minute particles of wax, and never 
have honey tubes, or cornicles, on the back of the abdomen — both char- 
acters in which they agree, however, with some of the lower plant lice. 
From all the corn-infesting plant lice they may be technically separated 
by the fact that their tarsi are single jointed, and bear a single tarsal 
claw, while the plant lice of this group have two tarsal joints and a pair 
of tarsal claws. 

Plant lice are among the most prolific of insects,* producing sev- 
eral generations annually, but they are commonly held severely in check 
by climatic, meteorological, and biological conditions ; that is, by sea- 
son, weather, and plant or animal parasites. They are, consequently, 

* Slingerland has bred twenty-five generations of a plant louse (Myzus achy- 
rantesf) in a single year (Science, Vol. XXL, 1893, p. 48); and Buckton shows (A 
Monograph of British Aphides, Vol. L, p. 80) that a single rose aphis ( Siphonopliora 
rosce might give origin, at its normal rate of unchecked multiplication, to over 
thirty-three quintillions of plant lice in a single season, equal in weight to more than 
a billion and a half of men. 



49 

capable of rapid and enormous increase when any of these checks are 
temporarily weakened to any considerable degree. As they affect the 
plant by abstracting the elaborated sap upon which its vital activity de- 
pends, the injury done is usually general, and especially is this true if the 
root be the part infested. Some species, however, in addition to the 
general drain upon the Life of the plant, cause a distinct local defor- 
mity to root or leaf in the nature of a gall, which protects them at the 
same time that it secures them food. Any crop liable to their attack 
in force is never long free from danger, but, on the other hand, a seem- 
ingly irresistible outbreak may disappear as quickly as it came, a slight 
and almost imperceptible change of conditions often taking tremendous 
effect on these delicate insects.* 

Economically, plant lice may be divided, according to the peculiari- 
ties of their life histories, into several groups or classes. Some genera- 
tion, or some part of some generation, may grow wings, fitting them for 
rapid dissemination, or the species may be without winged representa- 
tives. They may live through the whole season of their active life 
above ground, on exposed parts of the plant; they may spend the whole 
season under ground, upon the roots; or they may alternate, spreading 
each year from roots to stalk and leaves and back again. Whatever part 
of the plant they infest, they may live on a single host species, they may 
spread indefinitely from one to several others, or they may migrate 
definitely, by means of a fixed generation, from one species to another, 
requiring thus for their continuance two plant species often extremely 
unlike, f 

Finally, the sexual, oviparous generation (commonly the last to ap- 
pear in fall) may leave its eggs on the exposed parts of the plant last 
infested, or it may deposit them in the earth among or on the roots of 
its host. In the former case the destruction of the plant, or of its re- 
mains, will destroy the lice; in the latter, the eggs rest like a seed in the 
earth to stock the ground the following spring with a horde of young, 
ready to infest the succeeding crop if suited to their tastes and habits. 

All the plant lice of our present list of species infesting the roots 
of corn are, so far as known, \ subterranean only, producing no galls, 
but leaving their eggs in the earth over winter. They infest more than 
one plant, spreading from one to another species in an indefinite man- 
ner, not definitely migrating. The corn and grass root Lice (Aphis 
maidiradicis and Schizoneura panicola) develop early in the season 
winged forms by which they easily spread from field to field. 

* A marked illustration of this fact is afforded by the somewhat recent history 
of the grain louse (SiiJhonophora avence) in Illinois. (See Seventeenth Report State 
Entomologist of Illinois, p. X.> 

t The apple louse (Aphis mall), for example, passes from the apple to various 
grasses in midsummer, returning to the apple leaf in fall, and leaving upon the twigs 
eggs from which young hatch the following spring. The hop louse (Phorodon humuli) 
alternates in a similar manner between the hop and the plum; and a grass root louse 
(Schizoneura corni) between the grasses and the dogwoods. 

$ It has long been a general opinion that the corn root louse, presently to be 
discussed, is a subterranean form of the leaf louse (Aphis maidis), a surmise which 
I have failed to verify after many efforts extending through several years, and so 
have declined to accept. 



50 

Seven species of plant lice belonging to as many different genera,* 
have been found by us habitually infesting corn roots in Illinois. They 
are Aphis maidiradicis, Schizoneura panicola, Drama erigeronensis, 
Forda occidentalism Tychea brericornis, Rhizobius spicaius, and Geoica 
squamosa. By far the most important of these is the first mentioned, 
commonly known as the corn root aphis. This is, in fact, the only one 
on the list which infests corn primarily as a principal food plant, the 
others being essentially species of the meadow and pasture, attacking 
corn but lightly, and most commonly only when it follows grass. 

The association of all these species with ants, which care for them 
in many ways, some of them indispensable, and feed in turn on excre- 
tions of their insect charges, is a fact of special economic significance, 
since the ant most active in preserving the plant louse species must be 
taken into account as a factor in the economic problem. 

The Corn Root Aphis. 

(Aphis maidiradicis, Forbes.) 

(Plate VIL, Fig. 5 and 6; and Plate VIIL, Fig. 1-5'.) t 

No insect affecting corn is more deserving of the attention of farm- 
ers and entomologists at the present time than the corn root aphis. It 
ranks as a corn pest with the chinch bug and the army worm, loss in- 
jurious at any one time than these are locally and occasionally, but over- 
taking them, on the other hand, by its general distribution and the con- 
stancy of its attack. Although it lives upon the roots throughout the 
life of the plant, the principal damage is done at the same time as that 
caused by wireworms — while the corn is still small. It contrasts with 
the corn root worms with respect to the time of its most injurious ac- 
tivity, the latter coming in at about the time when the aphis generally 
begins to loosen its hold ; but the two agree in the fact that they make 
their first appearance in spring only on ground which has been in corn 
for at least a year preceding. The common root worm is confined 
throughout the season to the field in which it hatches, while the aphis 
presently scatters abroad, more or less freely according to the percent- 
age of the second and succeeding generations which develop wings. On 

* The following brief table may serve in a general way to indicate the correct 
genus and species of each of our corn root lice: 

Cornicles well developed Aphis maidiradicis. 

Cornicles reduced to dark rings Schizoneura panicola. 

Cornicles wanting. 

Last two joints of beak not longer than basal portion. 
Anal plate subglobose, strongly prominent. 

Third antennal joint about as long as first two combined, an addi- 
tional joint usually more or less distinctly formed from it, making 

the antenna? 6-jointed Trama erigeronensis. 

Third antennal joint very long, nearly twice as long as first two com- 
bined, antennae uniformly 5-jointed Forda occidentahs. 

Anal p'ate short, transverse, not at all prominent. 

Antenna* normal, as large as rostrum, third and fifth joints more 

than twice longer than thick Tychea brericornts. 

Antenna- minute, much smaller than rostrum, joints less than twice 

as long as thick. ..- Rhizobius spicatus. 

Last two joints of beak much longer than basal portion, anal plate retracted 

into dorsal segments Geoica squamosa. 

t A colored plate of the oviparous females, and of winged, wingless, and pupa 
forms of the viviparous female of this species, was published in the 17th Report of 
this office. 



51 

the other hand, although its worst mischief coincides with thai of the 
wireworms, it is not commonly the case that both are especially inju- 
rious in the same Holds, the wireworms following grass of the first and 
second year preceding, and the plant louse most commonly infesting 
corn on old corn ground only. As lands recently in grass are most, 
likely to contain the white grubs also, it is not a common thing to find 
the corn root aphis early in the spring in grub-infested lields. 

Its life history is now probably very well understood, hut thorough- 
ly effective remedial measures, I regret to say, are not yet certainly 
known. Rotation of crops will often greatly decrease or even prevent in- 
jury by dispersing the attack, hut we have no conclusive proof that this 
measure diminishes to any considerable extent the number of root lice 
in the country during any one year. It is therefore probable that this 
insect is increasing slowly in average numbers from year to year, and 
it may yet bring serious disaster to agriculture throughout the whole 
region best adapted to the culture of Indian corn. 

Although I have no data for a precise account of its distribution, 
it has been recognized by us in all parts of the State from Cairo to the 
extreme northern limit, and has been definitely reported outside Illinois, 
from Maryland, New Jersey, Indiana, Ohio, Kentucky, Minnesota, and 
Nebraska. It is altogether likely that it occurs in larger or smaller 
numbers throughout the whole corn belt. 

INJURY TO CORN. 

The corn root louse is a suctorial insect, taking only fluid food 
through a stiff beak, which it thrusts into the tissues of the plant it 
feeds upon, producing thus no external injury, nor, indeed, any local 
internal effect discoverable by ordinary methods of observation. Indi- 
cations of injury by this insect are consequently all of a general char- 
acter, affecting the entire plant, and do not materially differ from those 
caused by severe drouth, except in the fact that they are likely to be un- 
equal in different parts of the same field in a way to indicate no con T 
nection with the amount of retained moisture in the soil. 

A noticeably greater abundance in early spring in the lower parts 
of an infested field seems to be due to the greater abundance there of 
young Wi^'d^ on which the corn root aphis feeds at first. As soon as the 
corn starts to grow it may become infested, and even be killed outright 
before it appears above ground. We have, in fact, found the root louse 
on the plant as early as May 9, only four days after the field was planted. 

The dwarfing of the plant, especially in patches here and there, 
with a yellowing or reddening of the leaves — beginning of course with 
the lowest ones — and a general apparent lack of thrift and vigor, are 
sufficient to cause suspicion of injury by this louse, a suspicion which 
will be confirmed in part if numerous burrows' of ants are seen in or 
near the hills of corn. The presence of ants in the field may be over- 
looked after the ground has been recently cultivated, hut can scarcely 
escape attention shortly after a rain, when these little insects actively 
open up their burrows, heaping up the little pellets of earth about the 
openings of their nests. 



52 

The appearances described may, nevertheless, be due either to the 
corn root blight — a disease not caused by insects, and hence not treated 
in this report — or to the grass root louse, a species likewise attended 
by ants, but far less injurious to corn than the aphis under discussion. 
If the damage be due to the root blight, the root lice themselves will be 
few or wanting;* and if to the grass louse, the fact may readily be as- 
certained by an examination of the roots of the corn. 

The root aphis of the corn is of a bluish green color, slightly whit- 
ened by a waxy bloom. The form of the body is oval, and on the hinder 
part of the back are two short, slender, but conspicuous, tubes, standing 
erect or projecting slightly backwards, which may be seen by the glass 
to have open ends externally. These are called the cornicles of the 
aphis, or, sometimes, the ''honey tubes," it having been formerly supposed 
that they were the source of the abundant excretion upon which the ant 
attendants of the lice eagerly feed. The grass louse, on the other hand, 
is white in color, with a blackish head and other blackish markings, but 
without any tint of green; and it has no trace of cornicles, their place 
being taken by two minute openings in the corresponding segment of the 
body, each surrounded by a delicate brownish rim. 

The evidences of serious injury by the corn root aphis are, in short, 
an unusual dwarfing and discoloration of the corn, an abundance of 
small brown ants in the field, nesting among the hills, and, finally, the 
presence of the bluish green insects themselves upon the larger roots of 
the com, especially near the base of the stalk. 

The amount of injury may vary from a scarcely noticeable check 
upon the growth of the plant to a total destruction of the corn over 
considerable patches, up to half an acre or more. This more serious 
effect is, however, rarely, if ever, produced by the root louse alone. Like 
most insect enemies, — especially those of suctorial habit, which abstract 
the sap of the plant they feed upon, — the corn root aphis serves to in- 
tensify the effect of drouth and other unfavorable influences, and it is 
often difficult to say how much is to be ascribed to the action of the in- 
sect pest and how much to other causes cooperating. 

There is some evidence to the effect that a too serious check to the 
growth of the corn results in the early evolution of a great number of 
winged plant lice of the second spring generation, whose escape from 
the fields in which they start so breaks the force of the attack that in a 
favorable season very badly damaged plants may rally and make good 
corn; but if the insect injury is followed or reinforced by drouth, the 
corn may grow sluggishly the whole season through, and either fail to 
ear, or bear small imperfect nubbins only. Sometimes a field not in- 
fested the year before is permanently damaged in June, or even late in 
May, as the result of an early accidental concentration of the winged lice 
originating in other fields. 

INJURY TO OTHER PLANTS. 

No other crop plants are especially liable to injury by this aphis, 
unless possibly we should except broom corn and sorghum. Although 
not at all uncommon on these plants, it does not commonly thrive on 

* See also page 46, b. 



53 

them, and so far as my observations have extended, ran scarcely be 
called injurious to them. It has been observed in the field, however, or 
bred in the insectary, on the roots of a [lumber of other species of plants, 
some of which are, in fact, important to its maintenance. Many of the 
first generation hatch from the egg in the held before the corn is ready 
to receive them, and at this time young smartweed plants and foxtail 
grass (Polygonum and Setaria) are their principal resource. These 
plants harden early and lose the succulence which makes them especially 
desirable to plant lice, a fact which accounts in part no doubt for the 
early transfer of the lice to corn; but in fields of small grain, Setaria 
and Polygonum may continue to support the corn root louse at least 
until the second generation is well matured. Indeed, 1 have found this 
insect on the roots of smartweed more than a foot high as late as June 
17. Crab-grass (Panicum) also becomes infested, but less abundantly 
than the Setaria, and from the latter part of June throughout the rest 
of the season the aphis breeds abundantly on the common purslane 
(Portulaca oleracea). We have occasionally found it so abundant on 
purslane plants far removed from corn fields — besides paths in Lawns 
and in other similar situations — that one might well regard this as a 
purslane aphis, if it were not for the fact that this weed starts too late 
in the season to serve as food for the earlier generations. 

We have, further, experimental evidence that the corn root aphis 
can live on roots of ragweed (Ambrosia), having transferred May 8, 
1889, half-grown young of the second generation from smartweed roots 
to this plant, where they lived and fed until they acquired wings, five 
days later. The fall oviparous generation and the one preceding it have 
been repeatedly reported by my field assistants — who were constantly 
dealing with the root aphis and knew its characters perfectly — to have 
abundantly infested dock (Rum ex crispus), fleabane (Erigeron cana- 
dense), mustard (Brassica nigra), sorrel (Oxalis strict®), plantain 
(Plantago major), Hungarian grass (Setaria germanica), pigweed 
(Amarantus hybridus), and squash; but as these statements were not 
verified by successful transfers from these various plants to corn, they 
rest only on determinative evidence, notoriously unreliable with respect 
to the plant louse species. Indeed, an attempt at transfers of the sup- 
posed corn aphis found on squash, sent me from Ohio by Prof. C. M. 
Weed, entirely failed. A similar result was reached in an attempt to 
transfer known corn root lice from corn to wheat and oats, begun April 
22, 1889. Insects placed on roots of wheat in breeding cages April 22 
continued to live there until May 5, but without producing young. May 
11, however, all had left the plants. An earlier experiment, begun April 
10, had a like ending, and a precisely similar result was obtained in a 
parallel experiment with oats. 

The repugnance of this insect to the roots of small grain was re- 
peatedly shown also by field observations. Fields of oats and wheat on 
old corn ground, sometimes known to have been badly infested by the 
root aphis the preceding year, often contained in April and May large 
numbers of these root lice and their associated ants, the former feeding 
on the roots of smartweed and pigeon-grass growing with the grain, but 



51 

never being seen on the roots of the grain even where these and the 
grass roots were closely interlaced. 

The relation of this louse to other plants than corn has an im- 
portant economic bearing. For example, in fields on old corn ground, 
the first generation of plant lice are very noticeably more abundant early 
in spring in the lower parts of the field than elsewhere, especially in 
those parts so situated as to receive the wash from the remainder. I can 
at present only account for this unquestionable fact by the very much 
greater abundance here of young smartweed plants, doubtless due to the 
washing down of the seeds left on the ground in fall. This seems 
especially likely to be the true explanation, since the difference in the 
number of plant lice on low and high ground in the same field dimin- 
ishes greatly or entirely disappears with the advent of later generations 
and the scattering of the winged lice abroad. 

LIFE HISTORY. 

General Statement. — The corn root aphis passes the winter as an 
egg in the earth, in corn fields or, rarely, in other grounds where purs- 
lane grows late in fall, always, so far as known, only in the nests of a 
small brown ant about an eighth of an inch long, known to science as 
Lasius niger or its variety, L. niger alienus. This ant is the constant 
companion of the root louse throughout the year, living in burrows 
among the roots of the com. The aphis eggs begin to hatch about the 
time of the opening of the seed leaves of the smartweed or heartweed 
(Polygonum persicaria ), abundant in cultivated ground. This first of 
the spring generations is readily distinguished by characters of form 
and color from all that follow. Appearing usually before the corn is 
planted, it is dependent at first, in our region, almost wholly upon the 
young smartweed plants. The roots of these are laid bare by the bur- 
rows of the ants, and upon these roots, within their narrow tunnels, the 
lice will usually be found thickly clustered. Later, if the field be not 
planted to corn, our common species of pigeon-grass (Setaria) divides 
the attention of the lice, offering in fact, for a little time, a more succu- 
lent herbage than the rapidly growing smartweed. 

The second generation begins to apnear about the 1st of May, — we 
have one breeding-cage record of the 28th of April, — and by the middle 
of that month may he itself mature. Many of this generation are 
winged, while others are without wings,* the winged form first occurring 
about May 10. f These "migrant" root lice may live at first, like those of 
the preceding generation, upon smartweed and pigeon-grass, but more 
commonly they are transferred to corn by the little brown ant already 
mentioned, either in the same field or after they have flown to another. 
These ants not only carry from weeds to corn the root lice already in 
their possession, but burrow hills of corn in advance, eagerly seizing and 
co/iveying to their subterranean galleries winged root lice which come 
their way. 

* Two young of this generation, bora of the same mother in a glass tube en- 
closing a corn root, were kept by us until adult, when one proved to be a wingless 
aphis and the other winged. 

t This generation is at its best from May 15 to 20 in average years in Central 
Illinois. 



55 

The succeed in- generations arc not of special economic interest 
with 1 lie exception of the Last to occur — the autumnal, bisexual brood, 
by which tlie eggs arc laid. Both males and females of (bis brood are 
wingless, and live in the earth like their parents, occurring there from 
tbe 'middle of September to the middle of November. The eggs which 
they lay are taken in charge by their attendant ants and cared for 
during tbe winter. 

Number of Generations— Tbe eggs of tbe corn root louse begin 
to hatch as early as April 10, this process continuing, according to our 
observations, until May 2. Tbe adults of this earliest generation, the 
so-called stem mothers, were first seen by us April MS, and tbe last 
appeared in our collections exactly one month later. Tbe first of the 
second, or so-called migrant, generation originating in our breeding 
cages was born April 28, and the last on tbe 21st of .May. Migrant 
pupae were first observed May 10, and winged adults May 11. The evo- 
lution of winged forms of this second generation lias continued unques- 
tionably untif June 2, and possibly until June 8. Our earliest date for 
the bisexual brood is September 12, when an oviparous female was found 
iu a breeding cage. The first male was observed September 16; and 
male and female were seen in copula October 1. Living females of this 
brood have been taken by us from ants' nests as late as December 11 
(1893). Our autumnal dates for the collection of eggs are October 21, 
November 5 and 20, and December 11. 

Our numerous breeding cage experiments, although not one of them 
is continuous throughout the year, enable me nevertheless to give a 
fairly full account of the number and succession of generations. Stem 
mothers very young when taken (together with eggs), April 25, and 
probably hatched the preceding day, gave birth to young May 15, making 
the period of this generation twenty-one days. Young of the second or 
migrant generation born May 9 became winged adults May 28, thus 
requiring for their growth a period of nineteen days. 

In another case, young of the same generation born May 17 acquired 
wings June 4, the interval being eighteen days. Descendants of this 
migrant generation (the third of the series consequently) born June 8, 
were adult June 19 (eleven days), giving origin on that date to young 
of the fourth generation, which became adult on the 30th of June — 
again an interval of eleven days. Examples brought in from the field 
June 22 (probably of the third generation)* gave birth to young June 
24 — probably of the fourth generation. From this start a continuous 
series of generations was bredf to September 5, all adults of each genera- 
tion being in every case removed and destroyed by us before their young 
had begun to breed. Assuming that this experiment began with the 
fourth generation, the first of the fifth were born July 3 (nine days) ; 
of the sixth, July 10 (seven days) ; of the seventh, July 24 (fourteen 
days) ; of the eighth, August 5 (twelve days) : of the ninth, August 15 
(ten days) ; of the tenth, August 25 (ten days) ; and of the eleventh, 
September 5 (twelve days). On the 16th of September males of the 

* Other observations and collections show that these specimens may have be- 
longed to the fourth or even the fifth generation. They can hardly have been of 
earlier date than the third. 

t These root lice were maintained thus continuously on the leaves of the corn, 
for greater convenience and accuracy of observation. 
—5 E 



56 

autumnal generation appeared, belonging probably to the twelfth genera- 
tion from the egg. 

Prom the above account it will be seen that while the first three 
generations have an average life of nineteen days, the fourth to the 
twelfth followed each other at an average interval of precisely eleven 
days. Many of our observations show that a much earlier start and a 
more rapid growth are common, and that a greater number of genera- 
tions may consequently occur. Thus, although in the above account the 
stem mothers hatched April 24, we have collected young of this genera- 
tion as early as April 10; and our breeding records show that adults 
of this first generation may mature and young migrants may be born by 
April 28, a date more than a fortnight earlier than those used above. 
Adult (winged) migrants have been seen by us May 11 — again more 
than a fortnight earlier than the corresponding date just mentioned. 
Further, we have had young of the third generation May 13, if we may 
trust, an unverified report of Mr. F. W. Mally, who assisted me on this 
work in 1890. On the other hand, as I have counted generations from 
first-born to first-born, the life of a generation is here made too short 
for the average. 

No special attempt was made to determine the number of indi- 
viduals a single female may produce or the relative productiveness of the 
various successive generations. The fact is however worthy of record 
that a single stem mother- placed on a corn root in a breeding cage May 
4, brought forth her first young May 6 and her twelfth and last May 
15. At this time the first-born was a pupa, acquiring wings on the 19th. 
The stem mother lived until the 22d, and was then placed in alcohol. 
Another female of a midsummer brood brought forth fifteen young.* 

According to the results of experiments conducted for the purpose 
of determining the number of moults of the corn root aphis, and the 
intervals between successive moults, we find that this species moults 
four times, at average intervals of three or four days. Our most suc- 
cessful observations upon this and several other nice points of individual 
life historv were made on isolated specimens, each placed upon the root 
of a potted plant which was then passed through a small glass tube and 
covered with earth except where the tube enclosed it. To prevent the 
escape of the plant louse the ends of the tube were lightly plugged with 
cotton-wool. 

Migration to Uninfested Fields. — The last autumnal brood of the 
corn root aphis lives, so far as known, only upon roots of corn and purs- 

* As an effective illustration of the pressure which this p'ant louse species 
brings to bear upon the natural limitations on its increase, it may be worth while to 
say that assuming the correctness of the figures here given as to the normal rate of 
multiplication and the number of generations produced in a year, and further sup- 
posing that all the plant lice descending from a single female hatched from the egg 
in spring were to live and reproduce throughout the year, we should have coming 
from the egg the following spring nine and a half trillion young. As each plant 
louse measures about 1.4 mm. in length and .93 mm. in width, an easy calculation 
shows that these conceivably possible descendants of a single female would, if 
closely placed end to end, form a procession seven million eight hundred and fifty 
thousand miles in length ; or they would make a belt or strip ten feet wide and two 
hundred and thirty miles long. Since the natural checks upon multiplication keep 
this insect species within limits of relative insignificance, the above statement would 
have no practical value if these checks were uniform in action. It is because they 
are highly variable that the aphis species, capable of reproduction at a rate so enor- 
mous, able consequently to take rapid and great advantage of any circumstance 
even slightly favorable, are a constant and often hideous menace to agriculture. 



57 

lane, the latter being usually infested in corn fields only, and in these 
situations, consequently, the eggs are Jei't from which young hatch the 
following spring.* This first spring generation being always without 
wings, the rout aphis is practically confined for a little time to fields 
previously in corn. As a considerable pari of the second generation 
acquires wings, a general dispersal of adults begins almost as soon as the 
corn is out of the ground. These winged root lice do not, however, he- 
come sufficiently abundant for a considerable time thereafter to notice- 
ably affect fields not in corn the year before. Previous to the first of 
June this distributed attack can scarcely be detected, and not until July 
1 have we found it really serious anywhere. 

The first winged migrant w r as reared in our breeding cages May 11, 
and May 12 of another year an example was seen in the field. From 
this date forward, breeding-cage and field observations of the winged 
lice or migrants of this second generation were an almost daily occur- 
rence to May 28, and were occasional for a few days thereafter. 

Many scores of field observations of root lice on corn include no 
case of their occurrence in other than old corn ground previous to May 
19, on which date, in 1887, a single winged louse was found on corn after 
sod. This was on one of the upper roots, along which the small brown 
ant had mined for a considerable distance. Many other hills in this 
field were similarly mined by ants but contained as yet no plant lice. 
Next, May 21, 1886, a single winged female was found on corn roots in 
an ants' nest, the only aphis in the hill. This female began to produce 
young the next day. May 28, among many hills searched in a field of 
corn following upon grass, two were found with winged root lice, one 
of which had just produced a single young louse; and May 31 two 
winged lice were again found in corn planted on sod. In the month of 
June but three such observations are recorded in our notes, and these 
refer to small numbers only. Not until July 1 have we found winged 
and wingless root lice (generations two and three) sufficiently abundant 
in ground not previously in corn to be worthy of special attention. 

The evolution of winged root lice is not confined to the second 
generation, above mentioned, but continues throughout the season in 
numbers varying according to some law not yet ascertained. It is to 
be noted, however, that we have taken the winged form in August but 
once, although our collections of wingless specimens were made on 
twenty-seven days within that month. In September also the winged 
louse is. relatively rare, occurring but three times in twenty collections 
made on as many different dates. By November the viviparous genera- 
tions are all dead, as a rule, and the species is thereafter represented only 
by the sexual generation and the egg. 

RELATION TO ANTS. 

Seven kinds of ants have been found by us fulfilling the relation 
of host, guardian, and nurse to the corn root aphis; viz., Formica fusca, 
Formica schcmfussi, Lasiiis niger, Lasius niger alien us, Lasius inter- 
jectuSj Myrmica scabrinodis, and Solenopsis debilis. The occurrence in 

♦Among more than fifty lots of "stem mothers" of the corn root aphis collected 
by us in the field, every one was found in ground which had borne corn for at least 
the year immediately preceding. 



58 

this relation of all but the third and fourth just mentioned* is, how- 
ever, so rare that they need receive here no more than this passing men- 
tion, especially as their services to the aphis are, so far as observed, the 
same in character and value as those of the much more abundant species. 

The fact has already been mentioned in this paper that the sexual 
egg-laying generation of the corn root aphis — the last to appear in fall — 
is born in the galleries of the nests or homes of ants, and that here the 
sexes pair and the females drop their eg^s. As one explores these nests 
in November, when the root louse eggs are being: laid, he is struck with 
the relative independence of these oviparous adults, which are allowed 
to wander unattended through the burrows of their hosts as far as a foot 
or more from a corn root. We have found them, however, still feeding 
as late as November 5, and laying eggs November 21. These eggs, which 
are yellow when first deposited, but soon become shining black, and 
turn green just before hatching, are at first scattered here and there, as 
it happens, but are finally gathered by the ants for the winter in little 
heaps and stored in their galleries, or sometimes in chambers made by 
widening the gallery as if for storage purposes. If a nest is disturbed, 
the ants will commonly seize the aphis eggs — often several at a grasp — 
and carry them away. In winter they are taken to the deepest parts of 
the nests (six or seven inches below the surface in some cases observed) 
as if for some partial protection against frost ; but on bright days in 
spring they are brought up, sometimes within half an inch or less of 
the surface, sometimes even scattered about in the sunshine, and carried 
back again at night — a practice probably to be understood as a means 
of hastening their hatching. I have repeatedly seen these ants in con- 
finement with a little mass of aphis eggs, turn the eggs about one by 
one with their mandibles, licking each carefully at the same time as if 
to clean the surface. These anxious cares are of course explained by the 
use the ants make of the root lice, whose excreted fluids they lap up 
greedily as soon as the young lice begin to feed. They are not, how- 
ever, wholly dependent on this food sunrtly, at least in early spring, as 
I have seen them kill and drag away at that season soft-bodied insect 
larvae, doubtless to suck their juices out as food. This has been a some- 
what rare occurrence, however, and has rarely been noticed by us among 
ants which had plant lice in their possession. Once, however, ants of 
this species occurring abundantly in corn fields were observed September 
22 to carry bits of dead insects into their burrows, together with a living 
corn root louse. 

That the young of the first generation are helped by the ants to a 
favorable position on the roots of the plants they infest is quite beyond 
question. It is shown (1) by the fact that in many cases the aphis could 
not get access to such roots unless these had been previously laid bare by 
the tunneling of the ants, and (2) by the behavior of ants with mines 
already constructed, when the root aphis is offered to them. We have 
repeatedly performed the experiment of starting colonies of ants on hills 
of corn in the insectary and exposing root lice from the field to their at- 
tentions, and in every such instance, if the colony was well established, 

* Typical Lasius niger and its barely distinguishable variety alineus are almost 
equally at home in the corn field, and do not differ noticeably in their relations to 
the corn root aphis. 



59 

the helpless insects have been seized by the ants, often almost instantly, 
and conveyed under ground, where we would later lind them feeding and 
breeding on the roots of the corn. In many cases in the field, we have 
found the young root aphis on sprouting \\<'r<\± (especially pigeon- 
grass), which have been soughl out by the ants before the leaves had 
shown above the ground; and, similarly, when the held is planted to 
corn, these ardent explorers will frequently discover the sprouting ker- 
nel in the earth, and mine along the starting stem and place the plant 
lice upon it. 

We have also abundant evidence that ants excavate hills of corn in 
very early spring, when they have as yet neither eggs nor plant lice in 
their possession, and some days before the possible appearance of the 
second or winged generation. I can only account for this practice on 
the supposition that these ants expect later to obtain eggs or young 
with which to stock their burrows, made ready in advance. Certainly 
this is true with respect to the second generation of the root aphis. 
When winged lice of this brood begin to appear, it is a common thing 
to find the small brown ant scattering far and wide over fields not pre- 
viously in corn, and containing consequently no plant lice in any stage,* 
burrowing there the hills of corn, and carrying underground such corn 
root lice as come within their range. For example, a corn field on sod 
near Polo, 111., was searched May f 8 of a backward spring, after a period 
of frequent cold rains which had greatly retarded the work of the ants 
and the development of the corn root aphis. A few of the hills already 
burrowed by the ants were found with the grass louse only (Schizoneura 
jHinirola ) . and one with a single mealy bug (I)aetylopius), while twenty 
contained no insect whatever except the little brown ant, which was in 
full possession. May 28 two long rows of a field likewise on sod were 
searched carefully. Many hills were burrowed by ants, but only two con- 
tained the corn root louse, and in these were winged adults — one speci- 
men in one hill and two in the other, the latter with a single young one 
but just born. Our records are full of notes of observations made dur- 
ing the latter part of May in several years according to which ants were 
just beginning to mine corn hills on sod, no lice of any kind yet occur- 
ring in their burrows. Occasionally, in fact, an ant has been seen to seize 
a winged louse in the field, commonly by the wings themselves, and to 
carry it down out of sight. In one instance such a winged adult was 
found in a corn hill with its wings gnawed away near the body, as if 
to prevent its escape from the earth ; an operation to which ants are 
well known to subject their winged captives of the migrant generation. 
Confirmation of this practice is furnished by an observation made Sep- 
tember 22, 1884. A winged corn root aphis placed near an ant in the 
field was seized by the latter and carried about four feet to a newly 
opened formicary, and was then laid down while the ant went inside. 
An ant coming out of the nest afterwards carried the aphis into the 
earth. 

I need hardly say that the relations above described between the 
corn root aphis and these ants continue without cessation throughout 
the year, the succeeding generations being quite as useful to the ants 



60 

as those whose history I have thought it worth while to follow in detail. 
In order to determine more precisely the value of the services per- 
formed by their guardians, I arranged in several years a series of exper- 
iments designed to show to what extent the plant lice could help them- 
selves if left unattended. Owing to the waywardness of the ants, which 
in most cases refused to content themselves in confinement, but one of 
these experiments came to a successful issue. April 13, 1889, corn root 
aphis eggs were placed in the earth among smartweed roots to test the 
ability of the young lice hatching to find the roots for themselves. A 
check experiment was started at the same time with eggs placed in ar- 
tificial cavities beside smartweed roots. April 25 no insects could be 
found on the plants of the first experiment, while the cavities made in 
the second experiment contained young lice upon the roots in fine con- 
dition. 

RELATION TO THE CORN LEAP APHIS. 

Ever since Walsh, in 1862, doubtfully connected a leaf louse of 
corn, first reported by him,* with the root aphis described by Pitch from 
the roots of corn under the name of Aphis maidis,\ the relations of these 
insects has been a moot point. There has never been any evidence, how- 
ever, of their connection as simply different forms of the same species 
other than the facts that they belong to the same genus, that they re- 
semble each other more or less closely in specific characters, and that they 
infest different parts of the same plant in the same territory, and often 
at the same time. On the other hand, the differences of specific charac- 
ter are such that they may very well belong to different species, and 
should, indeed, have been held to be distinct until their identity had 
been demonstrated. They do not by any means vary together in abun- 
dance either in time or in place ; neither do they by preference infest 
the same species of plant. The corn leaf aphis occurs much more abun- 
dantly on sorghum and broom corn, especially the former, than it does 
on Indian corn itself; while the root louse occurs but rarely on those 
plants. Many other species whose roots are infested by the root aphis 
have not been known to support the corn leaf aphis at any time. The 
bare possibility, however, that these two forms may nevertheless alter- 
nate in such a manner that the one may be derived from the other throws 
some doubt on all propositions for an economic procedure, since if this is 
the case, both leaf and root louse must be taken into account in any 
measures intended to arrest the multiplication of either. 

On account of the economic importance of this point, elaborate ex- 
periments have been made necessary with both root and aerial lice. The 
distinctness of the two can only be shown by tracing the life history of 
each throughout the entire year under conditions such as to insure the 
production of the one from the other if such production be possible. 
Even then the demonstration would be incomplete unless both root and 
leaf lice had been followed generation by generation throughout the en- 
tire season from the ego- f one year back to the sexual generation and the 
egg of another year. These experimental conditions have now been sub- 

* Proc. Ent. Soc. Phila., Vol. I. (1863), p. 300. 
t Rep. Ins. N. Y., II., p. 318. 



61 

stantially fulfilled for the root louse only, as will be seen from what is 
presently to follow. The leaf louse, on the other hand, although it has 
been carried through the greater part of the year, including the entire 
fall and winter season, lias never yet been seen to produce a sexual gen- 
eration or an egg. Some experimental evidence has been obtained by at- 
tempt iug to bring the leaf aphis out of the root form by breeding the 
latter for many successive generations upon the corn leaf, and by similar 
attempts to rear the root louse from the winged leaf louse transferred 
to the roots of corn. These attempts have not thus far succeeded, and as 
the case stands at present, there is no satisfactory evidence of the specific 
identity of these forms, but a considerable body of proof to the contrary. 
The economic 1 recommendations of this paper are therefore based pro- 
visionally upon the theory of a specific distinction of the root and leaf 
aphides of corn. 

Observations and experiments on the leaf aphis were directed es- 
pecially to the time and circumstances of its earliest appearance in the 
fields, and to the time and method of its disappearance in fall; to the 
first with a view to learn whether it originates in migrants from the 
roots; and to the second in the hope of finding the sexual generation, 
and thus determining the place of deposit of its eggs. A few additional 
experiments in transferring the leaf aphis to the roots of corn and other 
plants were made to see whether we could thus demonstrate the possi- 
bility of a migration downward from leaf to root and the origin of the 
root louse from that of the leaf. 

Earliest Appearance of the Com Leaf Aphis. — The earliest date 
at which the leaf louse has been found by us is July 23 (1883), at which 
time it was common in a field of sorghum near Champaign. It occurred 
there in all stages of winged and wingless adults, pupae, and young, in 
association with the yellow sorghum louse (Chaitophorus flavus). It had 
doubtless started there as early as July 15. 

Our next earliest date for the leaf aphis is July 28 (1884), when 
wingless females were found by Mr. H. Garman at Formal, Illinois, — 
the first specimens of the year, — beneath the lower leaves of small corn 
in the field. Many stalks were searched, but the aphis was found in 
only two. Again, July 31, 1888, winged examples of Aphis maidis 
were common, crawling about on stalks and leaves of corn in a field near 
TJrbana, Illinois. 

Protracted and most careful search in corn fields which were heavily 
infested by the root aphis, made by Mr. C. M. Weed during the latter 
days of June, 1887, and by Mr. John Marten early in July, 1889, failed 
to discover a single leaf louse, although Mr. Weed found the winged root 
liaise on corn leaves June 23, 24, 27, 29, and 30. In several cases these 
winged lice had made themselves at home upon the leaf, and were pro- 
ducing young, from one to five occurring with a single female. June 
30 several winged root lice were detected on the rolled corn leaves at 
the tip of the stalk. Indeed, numerous earlier observations of winged 
root lice on leaves of corn are recorded in our notes; one by Mr. Gar- 
man as early as June 6, and others June 9 and June 11. On the last 
date, after tearing open the terminal tufts and rolled leaves of some 



62 

thirty growing plants, Mr. Marten found a single root aphis dead on the 
inner surface of the leaf. 

Transfer of Root Aphis to the Leaf. — This spontaneous appear- 
ance and breeding of the winged root aphis on the leaves of corn was 
strongly suggestive of a permanent and regular migration, and of a 
possible transformation there into the ordinary Aphis maidis in late 
June or early July. This hypothesis was tested by a series of experi- 
ments made in 1890 and 1891, the most conclusive of which was begun 
June 22 of the latter year. Corn growing in a trench in the insectary 
was stocked with root lice from the field, several "adult females 1 ' being 
confined to the leaf in a bag of Swiss muslin.* From this beginning, 
the successive generations were bred, specimens of each generation being 
transferred to a new leaf, until September 16 (at which time the sexual 
generation appeared) without the slightest approximation in any gen- 
eration to the characters of the aerial Aphis maidis. Several similar 
experiments made with sorghum plants instead of corn were even less 
successful, transferred root lice, though living and breeding for a short 
time, all dying, nevertheless, in from ten to sixteen days without more 
definite result. From these experiments we may conclude with some 
confidence that the corn leaf aphis does not originate in a migration of 
wingless lice from the roots. f 

Another class of experiments, less precise but less artificial, points 
to a similar conclusion concerning the winged root louse also. In these 
experiments large rectangular frames covered with cheese cloth were 
used to enclose tightly entire hills of corn in the field, as well a~ spe- 
cially planted hills in a plot of ground adjoining my insectary. In the 
field experiments these screens were made without doors, the hills being 
plentifully stocked with corn root lice in the beginning, and with their 
attendant ants, before the screens were set. In these cases the corn was 
left to itself until a sufficient time had elapsed, when the cover was re- 
moved and the plant searched for the corn leaf louse. In the small gar- 
den plot a screen was built large enough to enclose four hills of corn at 
once. At first the mistake was made of using too small a frame, and 
our results in 1889 were vitiated by the discovery that winged Apt) is 
maidis from the fields would sometimes settle on the cheese cloth cover 
where the corn leaves pressed against it, and there extrude their young, 
which were small enough to pass through the meshes of the cloth. There- 
after the enclosure was made so large that no part of the plant could 
touch it, even when full grown, access to the plants being given by 
means of a closely fitting door. The chief experiments of this series 
were the following: Six corn hills were covered in the field June 28, 
1889, selected because already stocked with the corn root aphis and the 
small brown ant Lasius niger alienus attending it. July 15 one hill was 
opened up and found unchanged, except that the ants had burrowed un- 
der ground and come to the surface far outside the space enclosed, thus 

* On account of a deficiency in the notes of this experiment, it is now impossi- 
ble to say whether any winged females were included in this lot. 

t Our notes of breeding-cage work and observation in the field show, never- 
theless, an occasional appearance of the wingless root form above ground on corn. 
in one case on the stalk, a few inches above the surface, and in anothei' upon the 
leaves at a much greater distance, where young were being produced. 



63 

providing for themselves and their charges a ready means of escape from 
confinement, as well as a passageway for the possible introduction of 
other plant [ice from without. July 25 and 30 two other hills were 
opened and found unchanged. From a fourth hill, examined August 2, 
and a fifth, opened September 2, everything had escaped, neither ants 
nor plant lice remaining; while the sixth, opened September 11, con- 
tained an abundance of the root aphis (winged adults and young) as well 
as the usual ants. In all these eases a critical examination of the en- 
tire plant above ground showed beyond question the absence of the aerial 
aphis, 

In the large breeding cage near the insectary, com was planted 
early in May, 1890, and the hills were stocked June ."> and 4 with ants, 
ant larva?, and root lice, others being added to the original stock June 
13, July 1, 10, and 16, August 2 and 18, and September 15. These re- 
peated additions were made necessary by the gradual disappearance of 
the root lice from the plants, which did not thrive perfectly at first, ow- 
ing apparently to the shade of the screen. Xo aerial lice appeared in this 
cage at any time during the progress of the experiment. This was termi- 
nated October 5, at which time root lice were still present on the corn. 

in another experiment, made June 16, 1891, by transferring the 
same species to hills of planted corn in the enclosure above described, the 
same results appeared. Boot lice were reared on all the hills through- 
out the entire summer, but there was no appearance of aerial lice at 
any time up to September 16, when the experiment closed. 

In 1891 both corn and sorghum were grown in this enclosure for 
experiment, and the plants were first stocked June 16. Additional speci- 
mens of both the l-oot aphis and the small brown ant were introduced 
June 27 and 29 and July 17, and ants alone, including their pupse, lar- 
vae, and eggs, July 24. By exposing single roots in little cavities in the 
earth and covering these with glass, it was easy to watch the behavior of 
the insects after they had been put in place, and it was thus learned that 
the sorghum hills were deserted almost at once. Consequently no root 
lice were found on the sorghum roots when the plants were dug up July 
13 and September 16. On the corn, however, the root aphis continued 
until the experiment was closed at the date last mentioned, hut no 
aerial lice appeared at any time on either kind of plant. 

Another smaller experiment was tried with a hill of sorghum only, 
transplanted to a box July 3, stocked with the root aphis and with ants 
of all stages, and covered with Swiss muslin. July 10 and August 1 
more root lice were added, and July 17 both lice and ants. Ants were 
observed at work in this enclosure July 11, 18, 20, 22, and 30, August 
5, 7, 10, 15, and 18, and September 1 and 16; but no aerial corn lice 
appeared at any time, and no corn root lice were seen after August 5. 
August 18 the common yellow sorghum louse (Chaitophorus flavus) 
had become abundant on stalks and leaves of the plant in the cage with 
the ants, and this condition of things continued until September 16, 
when the experiment was dropped. Apart from the negative result 
of this attempt to bring the corn leaf aphis out of the root louse, we 
get additional evidence that the latter does not thrive on the sorghum 
root. 



64 

The above evidence is, of course, negative only, and it is not at all 
certain that the conditions present were such as to favor the migration 
of the root lice to the leaves, if this were ever possible. Until further 
and much more numerous attempts are made to breed the leaf louse 
from the root form, and especially until such attempts are made by 
confining winged root lice of several generations on the leaves and tas- 
sels of corn and sorghum, the relations of these two corn aphides must 
remain somewhat in doubt. 

Disappearance of Corn Leaf Apjiis in Fall. — To determine the au- 
tumnal history of the leaf louse of corn, two lines of investigation were 
open; the first that of careful and continuous observation of the course 
of events in the field as the season closed and the plant lice disappeared, 
and the second that of insectary and breeding-cage experimentation 
continued through the fall and early winter. Both these lines have been 
carefully worked out under my direction; the first by Mr. Garman in 
1884, and the second by Mr. J. S. Terrill, followed by Mr. Marten, in 
the fall and winter of 1888 and 1889. Mr. Garman's observations ex- 
tended from October 6 to November 20, and were made almost daily 
in corn fields either at Champaign or Normal. As they related to the 
usual life history of the insect, they will be fullv summarized under the 
head of Aphis maidis itself, and it need here only be said that a careful 
following of the stages of the autumnal disappearance of this plant 
louse, as its food dried up and successive frosts destroyed the lingering 
remnants of the summer horde, gave no trace whatever of the presence 
of eggs, or of the occurrence of an oviparous generation. This conclu- 
sion was verified by hundreds of dissections made under the microscope, 
— all of which showed the presence of embryos in the abdomen, — and 
also by observations made upon small lots kept alive in the house. The 
experiments of 1888 and 1889, being of an artificial character and re- 
lating to the history of the plant louse under abnormal conditions, may 
properly be given here in full. 

October 9, 1888, adult specimens of Aphis maidis were transferred 
from broom corn to growing Indian corn in pots in the insectary, and 
eight of the lot finally settled upon the corn. Young appeared contin- 
uously, both wingless and winged forms, the latter, however, showing a 
disposition to leave the plant. By October 24 all the plants which had 
not been covered by bell jars were completely deserted by the lice, and 
under the bell jars the winged lice were evidently disposed to scatter and 
escape, many of them sticking to the glass in the film of moisture which 
covered it within. October 30 these leaf lice were still breeding freely 
on the corn, and likewise on wheat plants exposed to them under the same 
cover, producing both winged and wingless individuals. These condi- 
tions remained substantially unchanged, the lice breeding freely in all 
the inclosures in the insectary until March 19, 1889, when the experi- 
ment was discontinued with a considerable supply of these aerial lice 
still in our possession. February 14 one lot under a bell jar was placed 
outdoors to determine the effect of a change of temperature. This lot 
was not examined again until March 4, when all were dead, with no 
trace of egga, however, on the plants. Between September 11 and 



March 11 eight successive generations apppeared — practically eleven 

(lavs to each generation. 

Transfer of Leaf lAce to Roots of oilier I 'Inn Is. — A few experi- 
ments of this sort, made in October, L887, and in September, 1890, 
were quite without result, the plant Lice neither feeding nor breeding at 
that season of the year on roots of purslane or corn. They simply tried 
to escape, and died if prevented. A similar experiment tried with 
purslane in October, 1888, had a similar issue. 

NATURAL ENEMIES. 

Although various insect species, mites, ground beetles, and the like, 
have been found in more or less suspicious relation to the corn root lice 
in our breeding cages, and even in the fields, no known case has oc- 
curred to as of destruction by an insect enemy. It is, indeed, a remarkable 
fact that not a single hymenopterous parasite has ever been bred from 
the corn root aphis in all our long experience with that insect. It is 
true that root lice are much less parasitized than those feeding in more 
exposed positions, but they are nevertheless by no means commonly free 
from parasitic attack. 

The only natural check upon the increase of this root aphis which 
has come immediately to our notice is a parasitic fungus, Entomophthora 
freseniij detected October 16, 1889, infesting sexual individuals of 
this species found on roots of the curled dock (Rumex crispus) at Cham- 
paign, Illinois. Affected specimens were of a creamy or whitish color, 
and were literally crammed with the small oval granular spores of 
the Entomophthora. These so-called spores (properly "eonidia") are 
commonly of a smoky tint with a clearly distinguishable cell wall and 
granular contents. They measure 18-20 microns in length by 15-18 
in width. They are nearly spherical to short ovoid, and often have a short 
truncate, or slightly papillate, base. The fatal disease characterized 
by this fungus was generally distributed among the corn root lice in 
the field in which it was observed, nearly every lot of root lice detected 
there giving us examples of it, but it was not detected elsewdiere, and 
an attempt to extend it by contagion to the corn leaf aphis (A. maidis) 
resulted unsuccessfully. 

This fungus parasite is, so far as known, confined to the species of 
plant lice, of which it infests a great number. It is reported by Thaxter, 
in his "Entomophthorese of the United States,"* to occur in Maine, 
Massachusetts, Xorth Carolina, and Europe. 

ECONOMIC PROCEDURE. 

Our present knowledge of the life history of the corn plant louse 
suggests four possible methods of attack. (1) We may try the effect 
of a change of crop after any notable plant-louse injury to corn, in the 
expectation that corn planted on ground which contains no plant-louse 
eggs will become so slightly or so slowly infested, if at all, that no 
harm need be anticipated. (2) We may resort to fertilizers and other 
applications made to the young corn hill in spring in the hope of killing 
the lice outright or of supporting the plant against their attack at a 

*A fu!l account of this Etntomophthoiv is given in the paper cited. (See Mem. 
Bost. Soc. Nat. Hist. Vol IV., No. 6, p. 168.) 



time when this is likely to be most injurious. (3) Since the small 
brown ant cares assiduously for the eggs in winter and spring, we may 
assume provisionally the necessity of such care and strive to find means 
of so disturbing the nests of the ants or of breaking up and dispersing 
their contents in late fall or in winter that their stores of aphis eggs 
cannot be recovered by them, and so shall be left to perish. (4) Taking 
account of the early hatching of the eggs in spring, — several days, as a 
rule, before the usual time for planting corn, — and the dependence of 
the young lice for food at that time on sprouting weeds in the field, — 
especially smartweed and pigeon-grass, — we may seek to handle the 
ground in such a manner that there shall be no sufficient start of vegeta- 
tion to keep the lice alive. We may also delay somewhat, if necessary to 
this end, the planting of the field to corn. 

Rotation of Crops. — There can be no doubt that a judicious rota- 
tion of crops has the effect at least to diminish injury by the corn plant 
louse by distributing its attack; and there is also considerable reason to 
believe that it must result in the destruction, direct or indirect, of a 
certain proportion of the insects themselves. Corn planted on ground 
not previously stocked with plant-louse eggs must escape at any rate 
until invaded from without by winged individuals of the second genera- 
tion, and then, as a rule, it will be no more subject to injury than the 
other fields in its neighborhood. On the other hand, as the corn root 
aphis has never been known to infest to an injurious extent any other 
crop following corn, there is very little probability that the escape of 
the corn will be balanced by damage to other crops. 

We have many observations going to show that wheat and oats and 
the smaller grass-like plants in general are commonly soon deserted by 
such corn root lice as commence to breed on them — a fact which indi- 
cates that these plants are less suitable than corn to the maintenance and 
multiplication of these insects. We have also considerable reason to 
believe that many winged plant lice flying about in search of feeding 
and breeding grounds must be destroyed by some of the innumerable 
accidents to which these feeble and helpless insects are necessarily ex- 
posed. This measure of rotation may consequently have the effect to 
diminish to an important extent the number of corn root lice in later 
generations. Precise proof on these points is, however, very difficult to 
secure. Artificial breeding experiments are altogether too variable in 
result to serve the purpose, as our own attempts at a solution of this 
question show; and evidence must be sought in the field especially by 
making detailed comparative observations of parts of the same previously 
infested fields, planted here to corn and there to small grain. The rela- 
tive abundance of the lice late in May and early in June will go far to 
show the comparative utility of these crops as a food resource to the 
corn root aphis. 

Applications of Fertilizers and Insecticides. — Various field observa- 
tions have given us reason to conclude that fertilization of the soil will 
serve to support corn under the drain of aphis injurv, especially by 
enabling a stunted plant to rally more rapidly and completely after the 
insects have begun to scatter. The rapidity and vigor with which, in 
rich ground and in a fairly favorable season, corn will outgrow an 
apparently fatal injury by the root aphis is, in fact, often quite sur- 



r,; 

prising. Apart from this general statement I have only to report the 
result o!' a single scries of plol experiments tried in 189] with various 
fertilizers mingled with petroleum, crude and refined, as an insecticide, 
and with applications of salt, wood ashes, and lime. 

A plot of ground ten hills square, containing ninety-seven hills of 
corn, was selected on the University experimental farm at Drbana June 
is. 189-1, and surrounded by a continuous line of six-inch hoards sunk 
about three inches into the ground, with close-fitting joints, and with the 
earth well tramped both outside and in. The upper edge of the boards 
was thickly covered with coal-tar, subsequently kept fresh by repeated 
applications. These measures were intended to prevent all interference 
with The experiment, either by escape of the insects within the plot or 
by invasion from without. June 2(1 this enclosure was enlarged to con- 
tain twenty-three hills more. Fertilizers, and mixtures of fertilizers and 
petroleum, were applied to the hills of corn June 18 and 2.3, being 
worked into the soil about each bill ; and on the 26th lime, ashes, and 
salt were similarly applied. Of the ninety-seven hills in the first en- 
closure, forty-eight were found in the beginning to contain root lice and 
ants, and of the twenty-three bills in the second lot sixteen were simi- 
larly infested. 

Three fertilizers were applied : superphosphates, muriate of potash, 
and sulphate of potash ; each at the rate of three pounds to twenty hills 
of corn, and in each case half the hills under experiment were treated 
with the pure fertilizer and the other half with a mixture of fifteen 
ounces of petroleum to three pounds. One third of the above amounts 
were applied June 18. — the petroleum in these cases being the crude 
Lima oil,— and the remaining two thirds, June 23, when refined petro- 
leum was used. The following notes are condensed from the memo- 
randum filed at the time by the assistant* in charge of the experiment : 

Experiment I., Superphosphates. Experiment II., Superphosphates and Petro- 
leum. 
June 29, I. Ants and root lice numerous. 

29, II. Both insects present, but less numerous than in I. 
July 1, I. Ants and lice abundant. 
1. II. Ants present but no lice. 
7, I. Ants and lice abundant. 
7, II. A few ants but no lice 
15, I. Ants and lice comparatively abundant. 
15, II. Ants and lice both present but fewer than in I. 
Experiment III., Muriate of Potash. Experiment IV., Muriate of Potash and 
Petroleum. 
June 29, III. A few ants and lice found. 

29, IV. Dead plant lice discovered in one hill, both ants and lice oc- 
curring- generally but not abundantly. 
July 1, III. A few ants but no lice. 
" 1, IV. Ants alone discovered on roots about one foot from the hill, 
just outside the fertilized area. 
7, III. Ants and root lice found. 
7, IV. Ants but no lice. 
15, III. Ants plentiful ; lice common. 
15, IV. Few ants and lice detected. 
Experiment V., Sulphate of Potash. Experiment VI., Sulphate of Potash and 
Petroleum. 
June 29, V. Ants present but no lice. 

29, VI. A few ants present but no lice. 
July 1, V. Neither ants nor lice were found. 
" 1, VI. A few ants and lice in one hill. 
7, V. Ants and lice numerous. 
7, VI. Both insects present. 
15, V. No ants or lice detected. 
15, VI. Small colony of ants and a few lice in one hill. 



•Mr. J. S. Terrill, now of the Agricultural Experiment Station of Kentucky. The 
work was, however, done under the immediate supervision of John Marten, one ot 
my present entomological assistants. 



68 

The weather during the period covered by the above experiment was 
generally dry, but abundant rains occurred June 20 and 21, which 
seemed to dissolve the fertilizers and wash them into the ground. 

The lime, ashes, and salt experiments were entirely without effect, 
ants and plant lice occurring abundantly in all parts of the plot treated 
throughout the entire period of observation to July 28. This plot 
served consequently as a check upon the preceding experiment. 

Although the effect of the other applications seems from the above 
notes to be quite marked, the experiment is nevertheless indecisive, since 
the hills treated were not dug up when examined from time to time, but 
only searched as carefully as was possible without injuring the plants. 
July 28, when all the hills were removed they seemed, according to Mr. 
Marten's report, to be about equally infested, all appearance of difference 
having then vanished. It will thus be seen that these experiments have 
little value except as hints towards future work. The differences ob- 
served may nearly all have been due to a repellant effect of the sub- 
stances applied, in consequence of which the ants withdrew their charges 
deeper into the earth, with little diminution perhaps of the injury to the 
corn. 

Breaking up Nests of Ants. — In one experiment, begun November 
25, 1890, a strip of corn stubble three rods wide and ten rods long near 
the University premises at Champaign, was plowed six inches deep, half 
the strip being thoroughly harrowed also. The ants' nests among the 
corn hills were thus turned out and thoroughly broken up, except that in 
a few cases the plow did not go the full depth of the nests, but left the 
bottom undisturbed. The harrowing knocked the dirt out of the roots 
of the corn and broke up the fragments of the nests remaining in the 
clods. April 18, 1891, when the ground was again plowed, five ants' 
nests were found in this plot and thirteen in an equal strip beside it. 
All of these outside nests contained ant larva? of various sizes, while 
those inside the strip contained no ants but worker adults. Ten of the 
former lot of nests and three of the latter contained root lice also, on 
smartweed roots. 

In another precisely similar experiment, begun upon the same day 
in an adjoining field, a strip was plowed two and a half rods wide by 
twelve rods long, half of this being thoroughly harrowed, as before. The 
plowing averaged six inches in depth, but the plow ran considerably 
deeper under the corn rows, and the ants' nests were well broken up and 
scattered. April 17 of the following spring the ground was plowed for 
corn and thoroughly examined to determine the result of the experiment. 
The part which was harrowed contained three ants' nests, the remainder 
six ; while on an equal strip adjoining, thirty were found. None in the 
strip plowed in fall contained young ants, while every one of those aut- 
side contained them. Several wingless females were seen in the nests, 
one of them in the plowed strip. 

Neither the weather at the time nor that of the following winter 
was especially favorable to the success of such an experiment, the mer- 
cury reaching a maximum of 49° F. on the day the experiment began; 
and the winter following — that of 1890-91 — being unusually open and 



60 

warm. Further, there had been mure than a week of warm spring 
weather previous to April 18, the mercury reaching 72° on the 9th, 75° 
on the L3th, and 77° and 78° on the 17th and 18th respectively — tem- 
peratures at which ants as active as the little Lasius niger alienus might 
well disperse themselves and begin new colonies in unoccupied ground. 

These experiments afford, perhaps, scarcely a sufficient basis for a 
final conclusion as to the economic value of this method, but SO Ear as 
they go they are most encouraging. If we compare the treated, plots 
with the check plots beside them, we find (1) that the ants' nests in the 
former were less than a third as many as in the latter; (2) that all in 
the plowed and harrowed plots were destitute of ant larva' while in the 
check plots all without exception contained such larvae; and (3) that in 
the single plot first mentioned the ants" nests containing lice were less 
than a third as numerous as those in the plot outside.* 

From the above we can only infer the disastrous effect of this late 
fall and winter plowing upon the ants themselves, and, presumably, also 
upon the plant louse eggs they have in charge. It seems also quite 
pTObable that some, if not. all, of the nests found April 18 in the experi- 
mental plots had been established there by worker ants in spring, and 
were not remnants of the nests previously broken up, and if this were 
the ease the root lice found in them had doubtless been brought in from 
without. 

Starvation Experiments. — April 15, 1889, twelve young root lice 
recently hatched were placed in a cavity in the moist earth, which was 
covered with a glass slip so placed as to allow an examination of the in- 
terior. April 20 two of these root lice died; the next day half of the 
lot were dead; April 22 only two were living; April 23 but one; and 
on April 24, nine days from the beginning of the experiment, all were 
dead. 

May 14, 1888, a number of corn root lice of various ages, taken 
from the roots of young smartweed in the field, were placed in a glass 
vial with moist earth, the mouth of the vial being covered with gauze. 
On the 18th all were still alive, but by the 20th all had died, the earth 
in the vial still remaining moist. 

April 30, 1890, a number of eggs were placed in a cavity in ster- 
ilized earth and left to themselves. May 1 one young louse appeared 
from the only egg of the lot which hatched, and May 3 this was dead. It 
appeared from the foregoing that young of this species hatching in the 
earth and kept without food would die in from two to nine days. 

As a field application of this fact, an attempt was made April 16, 
1889, to starve the young lice in the ground by keeping down the 
growth of young weeds. A piece of ground was thoroughly harrowed 
in two directions with a cutaway disk harrow, and the weedier parts 
of the plot, several times additional. April 20, however, ants and lice 
were found both within and without the harrowed strip ; but the ants 
had no plant louse eggs in their possession where the ground had been 
harrowed. The result of this treatment was not especially encouraging, 

* By an unfortunate oversight no mention was made in the notes on the second 
experiment, of root lice in either the plowed strip or check. 



70 

the young weeds sprouting so freely and abundantly in the moist earth, 
to a depth of four or five inches, that it seemed impossible to reduce the 
food supply of the lice to any considerable extent by mechanical methods. 
Our present knowledge of effective economic procedure for the corn 
root aphis may be summarized in the form of the following recommen- 
dations: (1) that the fertility of the ground should be maintained as 
a general safeguard, and that cultivation should be so managed — espe- 
cially that of the lower parts of the field — as to prevent so far as prac- 
ticable the seeding of pigeon-grass and smartweed among the corn ; (2) 
that infested fields should be plowed deeply and thoroughly harrowed 
late in fall or during some suitable early winter interval; and (3) that 
a somewhat rapid rotation of crops should be systematically followed, 
corn usually being allowed to grow on the same ground but two years in 
succession. While some work remains to be done with reference to the 
precise value of these methods in practical application, there is no longer 
any doubt of their substantial usefulness, at least as a means of 
holding in check the injuries of the corn root aphis. 

DESCRIPTION OF CORN ROOT APHIS. 

Wingless Viviparous Female (Plate VIII., Fig. 1).— Body broad- 
oval. Head and prothorax blackish, remaining segments pale green, the 
first three with a transverse dusky mark at middle. Abdomen with 
blackish marginal patches on the second, third, and fourth segments, 
also numerous smaller spots of variable number and extent. The seventh 
and eighth segments have transverse blackish . marks at middle. An- 
tennae dusky towards tip and slightly so at base. Cornicles black, cauda 
and anal plate dusky. Beneath nearly uniform pale green, except the 
usual oblong transverse chitinous plate on the seventh segment; beak 
black at base and tip ; coxae, most of femora, tips of tibiae, and tarsi 
black. Antennae rather short, reaching about to the hind coxae, I and 
II short and thick, both combined about two thirds as long as III. IV, 
V, and basal part of VI about equal, the latter about three fifths as long 
as the spur, IV and V combined about equal to III. Four outer joints 
imbricated throughout, more distinctly on the spur, a group of sensoria 
on VI at the base of its spur, and one near the tip of V, as usual, rarely 
also one near tip of IV or III. Beak passing middle coxae, usually at- 
taining hind coxae. Lateral thoracic tubercles large and distinct, 
directed somewhat forward. Similar conical tubercles occur on the ab- 
domen, each surrounded by a dark ring: ; one on each side of the first 
segment, between the first two spiracles, and another pair on the seventh 
segment, each side of the chitinous plate. The cornicles are about as 
long as the third joint of the beak, rather slender and nearly cylindrical, 
often broad at base, the outlines straight or concave. The cauda is a 
little longer than its breadth at base, where it is widest, tapering to 
apex, which is broadly rounded. 

Length 1.4 mm., width .93 mm., antennae ."57 mm., cornicles .10 
mm. The young are paler in color, and have proportionally longer 
beaks and shorter cornicles. The chitinous space of the seventh seg- 
ment is almost wanting, and the cauda is shorter and broader, as in the 
]Dupa. 



71 

Pupa of Winged Viviparous Female (Plate VIII., Pig. 3). — Head 
obscure dusky, thorax pale reddish brown, abdomen dull pale green, 
without marking; beneath greenish. Cornicles blackish, cauda subtri- 
angnlar, dusky. Beak dark at base and tip; tarsi and tips of tibiae 

dusky. Antenna' short, and pale, last joint darker and proportionately 
longer than in the wingless female. Beak ami tuhercles as usual. 

Length L.61 nun., width .8 nun., antenna? .48 mm. 

Winged Viviparous Female (Plate VIII., Fig. 4 and 5). — Head 
black, thorax brownish black, ahdomen pale green, with black marginal 
blotches on the second, third, and fourth segments, and around hase of 
cornicles. Several transverse dusky marks in front of the cauda. Be- 
neaili thorax chiefly dark, with pale spaces about hase of legs; abdomen 
pale green, seventh segment as in wingless female. Antennae dark, pale 
at the articulations, length and proportions about as in wingless form, 
imbrication of joints IlI-VI distinct, III with six to eight mostly large 
sensoria in a nearly straight line, fourth segment with one or two sen- 
soria, sometimes none, V and VI as usual. Beak, abdominal tubercles, 
cornicles, and cauda, as in wingless form. Thoracic tubercles more out- 
wardly directed. 

Length 1.8 mm., width .9 mm., antennae .7 mm., cornicles .12 mm., 
fore wing 2 mm. 

Wingless Oviparous Female (Plate VII., Fig. 5). — Body dull green, 
with a glaucous bloom. Head dusky, prothorax chiefly dusky, three 
succeeding segments with a median transverse dusky blotch. Other 
small spots in series on dorsum. Beneath, head and prothorax dusky, 
two dark spots outside middle coxae, and dusky line before each of the 
hind coxae. The usual dark patch on the seventh segment. Antennae 
relatively shorter, not reaching hind coxae, proportions as in the pseudo- 
gyne; basal two joints and apical portions of the others dusky. Beak 
dusky, attaining middle coxae. Legs blackish, femora paler at base, 
anterior and middle tibiae paler except at tips ; hind tibiae greatly swollen 
and thickly covered with small sensoria. Tubercles smaller than in the 
pseudogynes. Cornicles and cauda as in the other forms. 

Length 2.3 mm., width 1.2 mm., antennas .8 mm., cornicles .2 mm. 

Egg. — Length .7 mm., width .3 mm. Yellow when first laid, be- 
coming black during winter and changing to green just before hatching 
in spring. 

Wingless Male (Plate VII., Pig. 6). — Body narrower than that of 
pseudogyne, greenish black with a glaucous bloom, head black, thoracic 
segments each with a transverse black band, narrow on the prothorax, 
wider on the mesothorax, both attaining the lateral margins, that on 
the mesothorax narrow and short, not reaching the margins. Similar 
short bands on the first and the last three abdominal segments, other 
smaller spots present. Antennae, legs, and cornicles blackish. Thorax 
beneath blackish, abdomen dark green, with the usual dark patch on 
seventh segment. Antennal lengths as in the pseudogyne, the joints 
thicker, joint III with two or three large sensoria near the middle, 
usually in line, and about ten very small ones irregularly distributed, 
grouped especially near the apex ; IV with 5 — 7 sensoria, one often 

—6 E 



large, the rest very small ; V with two or three very small ones and the 
usual large subapical one, and VI with one large and several small ones 
in a group at base of spur, as usual. Tubercles as in the females, the 
thoracic directed outwardly, the cauda as in the females. 

Length 1.1 mm., width .7 mm., antenna? .9 mm., cornicles .08 mm. 

This species is sufficiently distinguished from Aphis maidis by the 
breadth and large size of the thoracic and abdominal tubercles, which 
are slender and minute in maid is; by the longer beak, which passes the 
middle coxa? and usually attains the hind pair, while that of maidis 
seldom reaches the middle coxa? ; by the cornicles, which have a broad 
base, the sides tending to be straight or concave in outline, while in 
maidis the base is narrower, and the outlines more or less convex, these 
varying somewhat, however, so as to mislead in isolated examples; by 
the cauda, which in the adults is uniformly broadest at base, the sides 
tapering, while in maidis it is somewhat spoon-shaped, broad near 
middle, and narrower between middle and base; by the adults of maidis 
being much more elongate and narrow than adults of this species ; and, 
in the winged individuals, by the number and armament of the sensoria 
of the third antenna! joint, which are larger than in maidis and rather 
uniform in size, six to eight in number, and arranged in a fairly straight 
row, while there are thirteen to sixteen visible in maidis, of variable 
size and irregularly distributed along the under side of the joint. 

The oviparous female may be easily recognized by the swollen hind 
tibiae, covered with numerous minute sensoria; and the male differs from 
all the wingless individuals in the presence of a few large, and numerous 
minute, sensoria on the antenna;. 

ON THE ANTS ATTENDANT UPON THE CORN ROOT APHIS. 

hasius niger and its variety olienus* are so far the most abundant 
of the seven species of ants which we have found in attendance upon the 
corn root aphis that a discussion of the economics of this relation need 
scarcely take account of any other species; but as the most promising 
protective measures against this aphis are based on our knowledge of 
the life history and habits of this commonest corn-field ant, an accurate 
account of the latter is to be desired. Our notes on this subject cover 
the entire period since 1883, and enable me to give a fairly complete 
history of this species throughout the year. 

Life History. — The winged sexual forms, male and female, of this 
ant begin to annear each year, as early as the latter part of June (the 
21st to the 27th), hatching from pupae which may have formed late in 
May (27 and 28, by our notes). The emergence of males and females 
from the pupa continues throughout the season, certainly into October 
and probably to November, but the males perish before the winter. The 
females, however, having been fertilized and deprived of their wings, 
begin their separate excavations in fall, or continue with the workers in 
nests already established. There they hibernate, sometimes, at least, 
commencing to lay their eggs in fall, and living in spring through April 
and Mav. 



[= am eric anus wherever used in this report.] 



We have found the eggs of this species only November 1<», ::: April 
Mo, and May 20; but exceedingly small larvae certainly very recently 
hatched have been collected by us May 5 to 19, July 15, and September 
21. Our experiments have not, however, been conducted in a way to 

distinguish between eggs and young coining from fully developed fe- 
males and those from fertile workers. 

The larva 1 hatching from time to time throughout the summer may 
be found as pupae from the latter part of May through June, July, Au- 
gust, and September, to October 30, and even, according to a single ob- 
servation made at Urbana, to Xovember 20. 

Haunts, Actions, and Habits. — The nests or burrows of this ant, 
in which these breeding operations are carried forward, are widely dis- 
tributed in corn fields and grass lands, — especially in the latter, along 
the borders of roads and paths, — and also under stones and boards, in 
and under decaying logs, and in an indefinite variety of situations. In 
corn fields they are established almost wholly in the hills of corn, and 
remain here among the old corn roots throughout the season. As this 
is the commonest and most generally distributed of all our ants in Illi- 
nois, an exhaustive list of its places of habitation would have little 
present interest. It has never been found by us to form large settle- 
ments, or making mounds or conspicuous structures of any kind : but 
simply scatters its little burrows almost indiscriminately, living in small 
families rather than in great colonies or city-like aggregations, and pil- 
ing up only a small temporary heap of pellets around the mouth of its 
burrow. When its mines are explored they are found to consist of ir- 
regularly radiating and connected tunnels, rarely going to a greater 
depth than six or eight inches, or extending outward over a horizontal 
area of more than twelve or fifteen inches. Here and there in their 
course or at their extremities and at various depths are chamber-like 
enlargements in which their eggs and young and the eggs of the corn 
root aphis are preserved and cared for. Here also considerable collec- 
tions of the worker ants are usually found, — especially in winter and in 
times of summer drouth, — and in these chambers the female resides 
and lays her eggs. 

In April, May, and June the workers seem to be most numerous and 
active. In July and August their activity declines, particularly in the 
hottest and driest weather, although if nests be opened at these times 
the ants will be found in abundance. Again, in September, a period 
of bustling activity begins which continues until checked by the winter 
cold. 



* These egg's were obtained from a female brought in from the field October 
23, 1893. Two females taken at this time were found in earthen cells very much 
alike, each about three fourths of an inch long by half an inch wide, irregularly 
oval, with the inside nicely smoothed. No other ants were found in the immediate 
vicinitv. One of these females was placed October 25 in a Lubbock formicary be- 
tween sheets of glass and fed with sugar. November 5 she had made an oval cham- 
ber in the earth (exposed above where it came in contact with the glass), and from 
this chamber had begun to tunnel laterally. November 10 she was seen with several 
white eggs in her jaws, and November 12 with a still larger number. These eggs 
were kept in a mass, and hastily removed from the oval chamber to the tunnel on 
the slightest disturbance. The carelessness of some workmen broke up this formi- 
cary on the 16th of the month, and the eggs were not seen again. The eggs col- 
lected April 25 hatched May 5. Those obtained May 20 were from a nest in an oat 
field on old corn ground, which contained also a queen, or fertile female, great num- 
bers of worker ants, and larva? of various sizes — from those just hatched to others 
apparently full grown. 



74 

In ordinary winter weather of the milder sort, these ants are not 
absolutely motionless, but if disturbed crawl slowly and stupidly about, 
sometimes even painfully attempting to perform their usual duties of 
restoration and repair. We have not explored fheir nests in the coldest 
weather, when the ground is frozen to a considerable depth. 

During the first warm days of spring the thoroughly awakened 
ants begin to open up their burrows to the surface, and carry their 
own eggs and young and the eggs of the plant lice in their possession 
upwards and downwards according to the varying warmth of different 
layers of the soil. When the sun is shining brightly in the middle of the 
day they bring their charges to the more superficial chambers of their 
nests, or even expose them on the surface, but keep them farther down- 
ward at night and in cold and cloudy weather. The effect of this care 
upon the plant-louse eggs is shown by the earlier hatching of those cared 
for by the ants, and by the diminished number of those which fail to 
hatch at all. 

Although this ant is evidently chiefly dependent for food upon the 
corn root aphis and other plant lice fostered by it, it is not strictly lim- 
ited to this resource but, early in spring especially, has been found by 
us with freshly killed insects in its possession — caterpillars, carabid 
larvae, and the like. Sometimes in midsummer also it resorts to animal 
food. July 16, 1884, in digging into a hill of corn infested by the root 
aphis and this ant, I unearthed a carabid larva. This was suddenly at- 
tacked by one of the ants, which pounced upon it just behind the head. 
The larva struggled vigorously, but the ant soon fastened its jaws on 
the under side of the neck, just behind the head, and a little to one side 
of the middle line. After this the struggle lasted only a few seconds, 
when the larva became completely quiet, and allowed this ant and another 
to drag it away without the least resistance. I watched this operation 
for a few minutes with a glass, and then put both ants and larva into 
alcohol. Although the larva did not visibly bleed when bitten, it was 
apparently dead, and did not struggle at all when put into alcohol. 

June 2, 1891, an ant of the above species (Lasius niger) was found 
with a dead chinch bug in a wheat field, and three others were seen 
dragging live chinch bugs over the ground, one of which barely showed 
signs of life, a second of which moved its legs more vigorously, while a 
third, which an ant was dragging along by the beak, seemed scarcely 
at all disabled. 

Description (Plate X., Fig. 5 and 6; and Plate XL, Fig. 1). — 
Lasius niger and its variety alicnus belong to a group of small ants, 
the workers of which are about one sixth of an inch long, varying from 
yellowish brown to dark brown in color, and covered with a fine dense 
pubescence intermixed with scattered erect hairs, the surface therefore 
appearing dull or but feebly shining. The frontal area is faintly im- 
pressed, and the ocelli are indistinct. Their antenna? are 12-jointed, 
the third antennal joint shortest, the succeeding joints gradually longer. 
The maxillary palpi are long and slender, six-jointed. Between the base 
of the abdomen and the thorax is a short segment compressed above into 
a flattened vertical brownish scale, not distinctly notched above. The 
anal opening is circular. 



75 

These two forms are very closely related, and the differences ex- 
hibited do not seem to warrant more than varietal separation, although 
some authors treat them as distinet species. In typical niger the aver- 
age size is larger, the color of the female and worker is usually darker, 
and the antennal scape and the tibiae bear, among the usual pubescence, 
scattered, nearly erect, hairs, which are not usually apparent in alien us. 

The Grass Root Louse. 

(Schizuncura panicola, Thos.) 

(Plate VIII., Fig'. 6; and Plate IX.. Fig. 1.) 

This species was discovered on the roots of Fuuicunt, glabrum and 
other grasses by Mr. II. Pergande, at St. Louis, Mo., in .November, 
18;;, and first described by Dr. Thomas, in 1879, in the Eighth Ee- 
port of the State Entomologist of Illinois. The first observations of 
its occurrence in this State on corn were made in 1883, and it has been 
seen by us more or less abundant on the roots of various plants every 
year during the past eleven years. Its economic importance is but 
small, owing to the usually trivial numbers in which it occurs on corn, 
and the evanescent character of its attack. It is often important, how- 
ever, that the corn farmer should be able to distinguish it from the far 
more dangerous corn root aphis — a matter of no difficulty to a fairly 
good observer. It may be told at once from that species by its white or 
yellowish color, and by the absence of the projecting cornicles or honey- 
tubes characteristic of Aphis, these being replaced in the present spe- 
cies by a pair of minute circular openings on the hinder part of the 
back, each delicately rimmed with brown, and surrounded by a small 
dark patch. 

This root louse has been identified by Prof. Osborn as an alternate 
form with a species of the same genus, S. corni, Fabr., from the leaves 
of the dogwood (U. S. Department of Agriculture, Division of Ento- 
mology, Bulletin No. 22, p. 40) ; but from all available evidence I am 
not yet satisfied that the species here described as S. panicola ever 
leaves the ground except to fly from the roots of one food plant to those 
of another. It has been found by us in various underground situations 
from the early part of April until the latter part of November, as is 
shown by the following table, which gives also the plants on which it 
occurred. 



Date. 


Young. 


Adult wingless 
females. 


Pupae. 


Winged 
females. 


Apr. 5 




In log, with ants. 






Apr. 10-25 




In breeding cage; 
on grass roots 
with ants. 






Apr. 12 


Born in breeding 
cage. 









76 



Date. 


Young. 


Adult wingless 
females. 


Pupae. 


Winged 
females. 


May M 


Setaria in oat field 


Setaria in oat field 






May 17-2C 


Bom in breeding 
cage. 








May 23 


Corn. 








May 24 


Young grass. 








May 26 






Grass in oat 
field. 




May 28 


Young grass in 
corn field. 








June 1 


Setaria in corn 
field. 


Setaria in corn 
field. 


Setaria in corn 
field. 


Setaria in corn 
field. 


June 10 




Grass in corn field. 




Grass in corn field. 


June 13 




Corn (1883) and 
Setaria, 




Corn (1884). 


June 16 


Setaria, 








1 
June 17 


Corn. 




Corn. 


June 23 




Corn and Panicum. | 

1 


Corn. 


June 25 


Setaria. 


Setaria, grass. 




Corn, blue-grass, 
&c. 


June 26 


Smartweed in corn 
field. 


Smartweed in corn 
field. 






June 29 




Panicum. 






June 30 


Timothy in corn 
field. 


Timothy in corn 
field. 






July 3 




Timothy. 






July 13 




Setaria. Panicum, 
and corn. 


Setaria. Panicum, 
and corn. 


Setaria, Panicum, 
and corn. 


July 15 


Setaria in corn 
field. 


Setaria in co'-n 
field. 


Setaria in corn 
field. 


Setaria in corn 
field. 


July 25 




Sorghum. 






July 28 


Corn roots. 


Corn roots. 







77 



Date. 


Young. 


Adult wingless 
females. 


Pupa-. 


Winged 
females. 


July 31 


Sorghum and Pani- 
cum. 


Sorghum and Pani- 
cum. 






Auk- 4 


Panicum and corn. 


Panicum in sor- 
ghum Held. 


Panicum in sor- 
ghum tiekl. 




Aug. It 


Grass. 


Grass and sor- 
ghum. 






Oct. 2 




Sorghum. 






Oct. 10 




Grass. 






Oct. 12 




On sorghum roots. 






Oct. 20 




Corn in breeding 
cage. 






Nov. 25 




Lasius burrows in 
corn field. 







From the above table we learn that this grass root louse has been 
found by us on corn ten times, as follows: May 23, June 13 (twice), 
17, 23, 25, July 13, 28, August 4, and October 20 (in breeding cage). 
Other plants from the roots of which it has been taken are as follows: 
sorghum (five times) July 25, 31, August 11, and October 2 and 12; 
timothy (twice) June 30 and July 3; bine-grass (once) June 25; grass 
(seven' times) May 24, 26, 28, June 10, 25, August 11, October 10; Pani- 
cum (five times) June 23, 29, July 13, 31, and August 4; Setaria (seven 
times) May 1(1, June 1, 13, 16, 25, July 13 and 15; smartweed (Polyg- 
onum) (once) June 26. 

Thus we see that it has occurred fifteen times on cultivated plants, 
twenty-two times on the grasses, and once on a dicotyledonous species. 
It will further be seen that it does not appear to show a decided prefer- 
ence for any single food plant at any certain time of the year. A general 
preference for grass roots is shown, however, by the fact that in several 
cases where the roots of corn and grass were closely intertwined, the 
Schizoneura was found upon the latter only. It occasionally occurs on 
the roots of grass in fields planted with wheat, oats, etc., and wherever 
it is found in cultivated fields it is usually much the most abundant 
in those which were in sod the previous year. We have found it very 
common in the viviparous wingless form on the roots of various peren- 
nial grasses — blue-grass, timothy, and several native species— as the 
sod was broken up ; and there is little doubt that plants of this class 
furnish its principal sustenance. 

LIFE HISTORY. 

The life history of this species is still incomplete, all our observa- 
tions applying only to viviparous females, winged and wingless. Th' 



winter is passed in the latter stage, at least in part, as is proven by the 
occurrence of adult wingless viviparous females as early as April 5, in 
a log, on grass, attended by Lasius interjectus, and as late as November 
25, m the burrows of L. alieuns, in a corn field. The accompanying 
table shows that the young have been found as early as April 12 and as 
late as August 11. In the former case they were born in a breeding 
cage from stem-mothers introduced April 5, and in the latter they were 
taken from the roots of "grass" in a sorghum field. Between these dates 
they have been found frequently in May, June, and July upon the roots 
of various food plants, such as corn, grass, Setaria, smartweed (Polyg- 
onum), timothy, Panicum, and sorghum. 

The "pupae" (showing wing-pads) have been collected five times, 
as follows: May 26, June 1, July 13 and 15, and August 4. 

The winged viviparous female (winged pseudogyne) has been found 
by us eight times, as follows: June 1 on Setaria roots in corn field; 
June 10 on grass roots in corn field; June 13, 17, and 23 on roots of 
corn; June 25 on grass roots, on corn, and on blue-grass; July 13 on 
roots of Setaria, Panicum, and corn; and July 15 on Setaria roots in 
corn. Almost every year during the past ten years we have taken the 
winged pseudogyne during the month of June, and but twice (July 13 
and 15) in any other month. Pupae of this form have occurred, how- 
ever, August 4. June 25, 1889, winged forms were observed migrating 
from a corn field to a pasture — mostly blue-grass. They came from the 
roots of corn and grasses, in the corn fields, to the upper leaves of smart- 
weed, corn, and other plants, and, after resting there a few minutes, rose 
vertically into the air and Hew very rapidly, with the wind, to an ad- 
joining field of blue-grass, where they were taken in great numbers by 
sweeping. 

The early spring history of this species is best indicated by notes 
made April 5, 1884, by my assistant, Prof. H. Garman, now of the State 
College of Kentucky. Eoot lice whose identification as Schizoneura 
panicola has lately been verified by us, were obtained by him April 5 
from a nest of ants of the species Lasius Interjectus, which had estab- 
lished themselves in a rotten log at the edge of a corn field near Bloom- 
ington, 111. This nest contained likewise a number of eggs of aphides 
probably not of this species. The collection made was exposed to a 
colony of ants of the species above mentioned, which had been kept in 
a Lubbock formicary during the winter, with the result that the ants 
from the field were driven away and the Schizoneura and aphis eggs 
were seized upon and carried away into the burrows of the colony. 
Here all were cared for during about three weeks, when the observations 
terminated. A tuft of blue-grass was placed within reach of the ants. 
and vtpon this the root lice were colonized and began to breed April 
12, the young there born being alive and in good condition April 25. 

According to another experiment, begun by Mr. C. M. Weed May 
16, 1887, a wingless female of this species obtained from the roots of 
Setaria in an oat field was placed on that plant in a breeding cage. 
The next day she had moulted and given birth to young, additions to her 
brood being made at intervals to May 21, when the observation termi- 
nated. 



79 

On the 26th of May the winged pupae found in an oat field pre- 
ponderated greatly over all the other forms and stages; a fact possibly 
to be accounted for by the relatively scanty food supply in that situa- 
tion, and the consequent necessity for migration elsewhere. -June 10, on 
the other hand, in a corn field where winged specimens were present in 
huge numbers, the great majority of those observed were wingless fe- 
males in various stages. 

The closely related Schizoneura corni lives from September until 
June on the dogwood (Cornus), and from June until September on the 
roots of certain grasses. Our collections contain species of S. corni from 
the dogwood, but the most careful investigation of our large collection 
of root lice fails to reveal any evidence of its ever having been taken 
here on the roots of corn. 

RELATIONS TO ANTS. 

The accompanying table shows that our first and last collections for 
the year were not from the roots of plants, but from the winter nests 
of ants ; and here the grass louse evidently hibernates. When these nests 
are broken up, the ants evince no choice between the root lice and their 
own young in their eager and heroic efforts to carry them to places of 
safety. 

In the spring the ants dig new burrows around the roots of certain 
plants, and convey their charges to these new habitations; and during 
the summer they change them from one food plant to another, as the 
varying condition of the plants and the requirements of the root lice 
may demand. In return for these favors, this Schizoneura permits the 
ants to feed not only upon the "honey-dew" coming from the cornicles, 
but also on a waxy substance excreted from pores in the sides of the 
abdomen. We have several times seen the ants gathered about a de- 
tached mass of this wax, and apparently eating it. 

The ants collected in attendance on this root louse all belonged to 
the following forms: Formica schaufussi, Mayr (Plate XI., Fig. 2), 
once in attendance; L. inter jectus, Mayr; L. nig&r, Linn., and its variety 
aJienvs, Forst; and L. flaws, De Geer. The ant last mentioned is per- 
haps most commonly found in charge of it, the other species of Lasius 
mentioned differing but little with respect to the frequency of their 
occurrence in this relation. 

So far as now known, this insect is little likely to call for remedial 
measures, as corn is liable to injury by it only after grass, and the 
damage is, at most, slight and evanescent. 

DESCRIPTION.* 

Wingless Viviparous Female (Plate IX., Fig. 1). — Body ovate, 
more or less elongate, dirty white with a yellowish tinge, with a variably 
developed pattern of yellowish fuscous markings in the adult, dotted 
with white at the origin of the minute hairs which are scattered over the 
smooth surface of the body. 

Head rather small, but longer than the succeeding segments, uni- 
formly yellowish dusky, with a darker spot each side of the median line, 
a little in advance of the eye. Antenna? attaining middle of side of 
metathorax, not very thick, somewhat hairy, especially on outer joints, 

* By Mr. C. A. Hart. 



so 

colored like the head; apical joints dark brownish, spur nearly black, 
third joint pale except near apex; six-jointed, IV and Y nearly equal, 
Y a little the longer; IV about twice as long as thick: 111 nearly or 
quite as lung as IV and A* combined, and equally thick; II about three 
fourths as thick as I, and III half as thick as I ; I and II together two 
thirds the length of III alone; and VI half longer than Y, the spur 
constituting one fourth of its length. Y bears the usual round senso- 
rium, placed upon a slight prolongation of the apex beneath. On YI, at 
the base of the spur, is a round sensorium, posterior to which are three 
or more smaller sensoria. The eyes are quite variable in the extent of 
the black pigment, but usually of good size. The posterior tubercle is 
distinct, and bears three equidistant oval lenses radiating from the apex 
of the tubercle. Rudimentary ocelli sometimes visible. 

The prothorax bears above an irregular oblique spot, with dark 
outline, on each side of the disk. Dark lines, in line with these spots, • 
lie on each side in the transverse thoracic sutures, 'becoming double 
posteriorly, and from these a double row of small spots continues to the 
tip of the abdomen, sometimes obscured by the discal markings of the 
segments. The four segments behind the head are almost entirely fus- 
cous, except on the suture and at the sides of the first abdominal seg- 
ment. The three or four segments preceding the cauda are yellowish 
fuscous except near the lateral margin. The other abdominal segments 
show faint mottled fuscous bands. The cornicles are very distinctly 
indicated by fine dark rings nearly level with the surface, surrounded 
by a dark blotch. Cauda very short, subtriangular, not projecting, it and 
the anal plate yellowish fuscous, hairy. 

Beneath slightly paler than above, with markings of similar color; 
legs and beak brownish yellow. The beak attains the base of the abdo- 
men, last two joints dark brownish yellow, tip black. The basal two 
joints are together about twice as long as the third and fourth com- 
bined. The third joint is slightly broader than the others, about as 
long as broad ; the fourth joint is half longer, pale-ringed just before 
the tip. Legs nearly smooth, femora darker apieally, tibiae paler ex- 
cept at base and apex, claws dark, large. The abdomen has a marginal 
row of dark blotches, in which are situated the spiracles, and above 
these, a large subcircular excretory pore on segments 1-4 and 7. A 
similar large oval pore lies just below the lateral margin of the pro- 
thorax. These are homologous with the tubercles of the corn root louse, 
and perhaps with the cornicles also. Below the spiracles is a row of dark 
spots in the sutures. The seventh segment bears the usual transverse 
oblong brownish yellow plate. 

Length 1.5 mm., breadth .9 mm., antenna .5 mm. 

Described from numerous specimens from roots of grass and corn. 

The young show the usual differences of size and color, and pro- 
portionate greater length of appendages. The antenna? have but five 
joints, the third proportionally shorter. 

Pupa. — Oval, more elongate, yellowish white, head and thorax 
dusky, no distinct markings except the double row of spots. Antennas 
about attaining base of posterior wing-pads, with suture between Til 
and IV impel feet. ^Ying-pads attaining middle of second segment be- 



SI 

neath, posterior pair pale, turned downward more than the anterior, 
which are brownish dusky. Plate of seventh segment beneath indis- 
liiici l\ marked. Tip of abdomen hairy. 

Length 1.13 nun., breadth .6 nun., antenna .38 mm. 

Described from five specimens found on grass routs. 

Winged Viviparous Female (Plate VI IP, Fig. 6). — Elongate, 
smooth, with sparse inconspicuous hairs, dirty whitish, varied with fus- 
cous and dark brownish, dotted with white at origin of hairs. Head 
above and mesothorax above and below dark brownish, edges of meso- 
and meta-thoracic plates with blackish outlines. Remaining surface 
markings fuscous brown, sutures whitish. 

Antenna' fuscous brown, apex darker, base of third joint paler, ba- 
sal two joints one half thicker than the others; IV a little more than 
twice as long as thick, V a little longer, VI nearly half longer than 
IV, the spur three eighths of its length; 111 about equal to V and VI 
combined; I and II combined about equal to VI. Sensoria distinct, one 
at tip (beneath) of joints III, IV, and V, and at base of spur on VI, 
last two quite large, that on VI accompanied by the usual group of 
smaller sensoria. Often one at middle also of III, and sometimes a third 
near by it. Eyes brownish black, ocelli distinct. A pale notch on-hinder 
margin of head just within each eye. 

Prothorax with a dusky hand anteriorly, behind this a pair of large 
transverse spots, sometimes a small pair behind these. Mesothorax with 
pale spots at sides. Metathorax with a narrow transverse mark of dusky 
brown. Wings with a granulated surface, veins and stigma light brown- 
ish, stigma half as wide as long on costal margin; cubital obsolete two 
thirds of distance from base to the fork; stigmal vein but feebly curved. 
Running parallel to the posterior margin of the postcostal vein and 
stigma, and separated from them by a narrow paler interval, is a dis- 
tinct and narrow thickening and darkening of the wing. 

Abdominal segments with a row of marginal blotches, one on each 
segment. The double row of small spots in the sutures is present, but 
confused with the discal markings. First and second abdominal seg- 
ments each with a short transverse discal hand; bands of next three seg- 
ments more or less confluent, forming a fuscous brown patch ; sixth 
segment with a long discal band ; those on seventh and eighth extending 
to margin. Cornicles distinctly indicated by a fine dark ring in the 
marginal patch of the sixth segment. Cauda short, not projecting, it 
and anal plate fuscous brown, hairy. 

Beak as in viviparous female, attaining hind coxa?. Prothorax most- 
ly pale beneath ; mesothorax pale only around the coxa? ; metathorax 
with blackish transverse line, ends of latter partly surrounding coxa?. 
Legs darker fuscous brown, first tarsal joint prominent. In the suture 
back of the prothorax is an elongate spiracle in a small transverse dusky 
brownish spot ; just below the margin of the prothorax is a large oval 
excretory pore. The abdomen beneath is pale, first and second seg- 
ments, and sometimes the sixth, each with a short discal transverse 
line. Seventh with usual oblong dark plate, which is hairy like the anal 



82 

plate. An indistinct row of short transverse lines in the sutures ex- 
tends back from the hind coxa? on each side. Exterior to these is a 
row of light brownish spots including the pale spiracles. The spot on 
the first segment combines with the marginal blotch. In the blotches, 
on the first and seventh segments, and just below those on the second, 
third, and fourth segments, are large circular excretory pores similar 
to those on the thorax, outlined by a fine darker line. 

Length 1.8 mm., breadth .8 mm., antenna .03 mm., fore wing 1.8 
mm. 

Described from five specimens, three taken on grass roots, one on 
corn root, and one resting on corn leaf. 

Schizoneura panicola, Thomas, is nearly related in habit and struc- 
ture to the European 8. venusta, of Passerini, but differs from that spe- 
cies, according to Passerini's very brief description, in the color of the 
head and abdominal fasciae, which are light dusky instead of black. » s '. 
panicola differs also from S. venusta in the absence of the discoidal 
patch on the abdomen, and in the longer beak — reaching the hind coxa?, 
while that of venusta is said to extend only to the middle coxa?. The 
latter species is given by Passerini as occurring in Europe in autumn 
on the .roots of Setaria viridis, S. glauca, S. italica, Panicum glabrum, 
Eragrostis megastachya, and Ceratocliloa australis; also in the month 
of June on the roots of wheat ("Aphididae Italica?," p. 69). 

Trama erigeronensis, Thos. 

(Plate IX., Fig. 2.) 

This root louse is included here because it has been found a few 
times in corn fields under circumstances to indicate its probable occur- 
rence on the roots of corn itself. It is not strictly a corn insect, how- 
ever, so far as we now know. 

We have at hand specimens of the wingless viviparous female that 
have been taken as follows: March 19, (situation not given) ; April 1, 
from an ant hill (Lasius mixtus), on grass and a dicotyledonous weed; 
April 5, under a log at edge of corn field attended by Lasius niger; 
April 8, at roots of old corn; April 9, from an ants' nest; April 11, 
from roots of blue-grass, attended by Lasius interjectus; April 23, from 
nests of Lasius; April 26, in Lasius nest in old log; May 7, taken in 
corn field; November 25, from roots of Panicum, in corn field, with 
ants. Thus we see that this species has been collected here once in 
March, seven times in April, once in May, and once in November. 

Specific determinations have been made of the following species of 
ants attending this root louse; Lasius niger, L. mixtus, and L. inter- 
jectus. It is attended by about the same species of ants as the other 
root lice treated in this publication, and the range of food plants as 
shown above is also about the same as those given for several other 
species. 

DESCRIPTION.* 

Having a large series of this perplexing species, which is quite evi- 
dently the same as that described by Dr. Thomas in the Eighth Eeport 

* By C. A. Hart. 



83 

of tin's office (p. 168) as a Tychea, and again by Mr. <). W. Oestlund, 
in his "List of the Aphididae of Minnesota" (p. 56) as Tychea radicola, 
a full description is here submitted, Erom which it may be smi that an 
imperfect knowledge of the species has caused conflicting statements. 
The number of antenna 1 joints, as well as other characters, throw it out 
of Tychea, and place it in Trama, as defined by Koch. 

Wingless Viviparous Female. — Body broad-ovate, very convex, ab- 
domen often subglobose, surface smooth, dirty whitish, a few sparse 
hairs on antennae and. legs. 

Head rounded on front and sides, base broad, about twice the length, 
an oblong dusky spot extending from the base of the beak over the ver- 
tex, between the antennae, nearly to the posterior margin of the head, 
wider behind, divided by a whitish median line. Fully developed an- 
tennae with six distinct joints, dusky whitish, darker apically, the spur 
or sometimes the entire apical half of VI dark brown or blackish, tip 
reaching posterior margin of mesothorax. Joint I very short, trans- 
verse; II nearly as thick as I at apex, but narrowed strongly towards 
base, about one half longer than I; III still longer, but not as long as 
I and II combined, about twice as long as thick ; IV as long as II ; V 
as long as III, or a little shorter, wider apically; VI broad fusiform when 
seen from above, thickest near middle, tapering to base and to apex of 
spur; basal part of VI as long as V, spur about one fourth of total 
length of joint. Even in some good-sized examples the suture between 
joints III and IV is imperfect, and these two joints are shorter, espe- 
cially IV, which becomes distinctly shorter than II. In other specimens 
of the same lot, for example one 1.8 mm. long. III and IV are much 
shortened and completely united into one joint, which is very little longer 
than VI. V is also shorter, being about as long as II. Sensoria mod- 
erate in size, round, one, as usual, at apex of V and one at base of spur 
on VI, with one or two very indistinct minute sensoria adjoining it on 
the posterior side. • Eyes small, ocular tubercle feebly elevated, with 
three lenses as usual. 

Thorax and abdomen unicolorous, prothorax separated from meso- 
thorax by a lateral constriction, in front of which the side margin is 
subangulate. The dorsum is provided with numerous glands for the se- 
cretion of a waxy substance, which rises in short columnar tufts from 
each gland, giving an appearance of rows of tubercles. Alcohol soon 
dissolves most of the excretion, and even obliterates all traces of many 
of the glands. These glands are arranged in regular series, appearing 
in fresh specimens in alcohol as clear smooth spots encircled by a fine 
dark line. There are six longitudinal rows, each with one gland on 
each segment, equidistant on the abdomen, the outer row being at the 
lateral margin. The two middle rows approach at the base of the ab- 
domen, and are close together on the thorax and head, the head having 
four unequal glands in each row, placed within the dusky patch. The 
other four rows do not appear on the head, and are very indistinct on 
the thorax, excepting the prothoracic spot of the outer row, which is 
small but distinct, and below the side margin, those on the other tho- 
racic segments being dorsal. On the abdomen, the outer row consists of 
large lateral spots ; the seventh segment has but four spots, two lateral 



84 

and two dorsal, the latter small and inconspicuous. Cornicle.- wanting. 
The anal plate, eanda, and a short and narrow transverse band on the 
eighth segment above, are light yellowish brown, a whitish line on the 
anal plate just behind the cauda. x\nal plate strongly prominent, sub- 
globose, very convex below and more flattened above, minutely scabrous, 
clothed with rather long incurved hairs; cauda represented by a shorter 
subtriangular elevated plate on its upper surface. 

Beak brownish dusky, tip black, attaining or slightly surpassing 
hind coxa?, apical joint about as long as last antennal joint, penultimate 
joint about half as long, and somewhat thicker, being about as long as 
thick; lunate marks at its base distinct; apparent basal joint slender, 
about two and a half times as long as the apical two combined. Legs 
rather short, light brownish dusky, coxa? paler, sutural lines In-own 
about coxa?, two distinct claws and two tarsal joints on all the legs, tarsi 
and claws dark; fore legs very close to head. Prothoracic spiracle light 
brown, distinct, below the lateral gland. Abdominal spiracles each in 
the posterior margin of a small brownish spot, anterior margin of spira- 
cles finely outlined in black; sometimes an inner row of light brown 
spots, one beneath each abdominal spiracle. Seventh ventral segment- 
with a thickened and slightly darker plate at middle, which has at 
each end a group of sparse hairs. A few hairs on the ventral segments 
preceding the seventh. 

Length of body 2.2 mm., greatest width (across abdomen at mid- 
dle) 1.1 mm., antenna .55 mm. 

The young are more slender, with long beak and five-jointed an- 
tenna?, or four- jointed in the youngest. 

Described from ten lots of specimens. 

The cauda and anal plate and antennal structure will distinguish 
this species, in case the glands are not evident, from the others infesting 
corn. 

Forda occidentalis, n. sp. 

(Plate IX., Pig. 3.) 

Another root louse which has been found on corn in unimportant 
numbers is a species of Forda, here described as new. It seems to be 
mainly a grass root louse, and has been taken by us eight times, as fol- 
lows: April 4, (no situation given); April 10, on Capsella bursa^pas- 
/oris, attended by Formica fusca gagates; April 11, on roots of blue- 
grass in edge of corn field, with Lasius interject us; April 23, from a nest 
of Lasius; April 28, in blue-grass sod, attended by Latins niger; April 
30, in a pasture, with Lasius niger: May 7, in a corn field; May 31, 
on roots of corn, on sod ground, attended by Lasius. 

It will be seen that these collections have all been made in earlv 
spring, and with but two exceptions in the month of April. The life 
history of this species is thus unknown. 

DESCRIPTION.* 

Wingless Viviparous Female. — Body oval or ovate, smooth, uni- 
form light glaucous green, sutures not conspicuous, body and appen- 
dages sparsely covered with fine and rather short hair. 

* By C. A. Hart. 



85 

Head rather broad and subtruncate in front, width at base about 
twice its length. Antenna' distant, each in a short broad groove or im- 
pression, five-jointed in the mature individual, moderately long and 
slender, attaining the sides of the metathorax, slightly darker than the 
body, fifth joint and apex of fourth pale brownish; joint 1 aboul twice 
as thick as III, its posterior side about equaling its basaJ diameter; II 
a little longer and more slender, about twice as long as thick; III the 
most slender and much the longest joint, being nearly twice as long as 1 
and II combined; IV and V aboui equal, each longer than II. and 
combined about three fourths as lone; as III, spur of V tapering, short, 
extending beyond the sensdrium about as far as the diameter of V at 
base. On the lower side of the apex of IV is a large round sensorium, 
and at the base of the spur of V is an extremely large one, semicircular 
or sublimate, fully as wide as the diameter of III, strongly convex, 
glassy and apparently transparent when looked through in profile. Two 
or three minute sensoria adjoin it on the distal side, next the spur. On 
one antenna there is an additional sensorium on TV towards the base. 
Eyes moderately large, placed near the posterior angle of the head, ocular 
tubercle broad and rather high, showing in alcoholic specimens three oval 
lenses, their long axes radiating from the apex of the tubercle. 

Prothorax set off from remainder of body by a slight constriction 
or deepening of the suture, and usually showing an oblique impression 
on each side above. Remaining body segments without distinct mark- 
ings or structures above, gradually shorter to posterior extremity. Eighth 
segment, cauda, and anal plate pale brownish, the former small and 
short, the cauda reduced to a subtriangular plate on the upper surface of 
the anal plate, the latter one half longer than the cauda and as long 
as the seventh segment, semiglobular, minutely scabrous, clothed with 
fine short hair, a white line adjoining the apical margin of the cauda. 

Beneath, colored as above ; beak long and slender, reaching middle 
of abdomen in adult, base and apical joint pale brown, the latter tipped 
with black, as thick as joint II of the antenna?, and as long as antennal 
joints I and II combined; penultimate joint half as long, and one half 
wider than its length ; apparent basal joint about twice as long as the 
apical two combined, pale and slender. Legs moderately long, each with 
two distinct claws and two tarsal joints; coxa; slightly darker. Seventh 
ventral segment often dark, eighth concealed at middle, anal plate 
beneath with color and surface as above. Spiracles pale brownish, very 
inconspicuous. No glands or tubercles seen. 

Length of body 2.1 mm., greatest width 1 mm., antenna? .75 mm. 

The young are similar to the adult, antenna 1 five-jointed, III a little 
shorter than in the adult. 

Described from six lots of specimens. 

The clear pale green color, greatly elongated third antennal joint, 
very large sensoria. and absence of cornicles, easily distinguish this 
species from other root lice. 



86 

Tychea brevicomis, n. sp. 

(Plate IX., Fig. 4.) 

This species of root louse is not important, and has not been known 
to occur in destructive numbers, but from its occasional presence on corn 
' roots, it deserves mention along with others of its group and habits. 

A colony of this Tychea was found on corn roots at Normal, 111., on 
the 28th of July. The specimens in this collection all appear to be 
young pseudogynes, or wingless viviparous females, from about one third 
tu two thirds grown. A large adult wingless viviparous female was 
taken on the 25th of October from an ants' nest in a pasture field near 
Champaign. 

Description.* 

"Wingless Viviparous Female. — Body broad-oval, pale dirty whitish 
in alcoholic specimens, smooth, sutures not distinct. 

Head short, rather narrow between antennae, but very broad at base, 
which is more than three times as long as the frontal margin, the union 
between head and prothorax being very close; lateral margins concave, 
a pale dusky brown patch occupying the anterior surface between the 
antennas, terminating behind with a semicircular irregular margin, not 
extending towards the acute lateral angles nor attaining the hind mar- 
gin. It is divided by a median whitish line, on each side of which is a 
white glandular dot. An angular brownish patch also surrounds each 
eye. Antenna? short, but rather slender, hardly surpassing the posterior 
margin of the prothorax, five- jointed, uniform light brownish, with pale 
sutures; I short, twice as thick as III, and not as long as thick; II one 
half longer than I and nearly twice as long as thick; III nearly as long 
as I and II combined; IV very short, about as long as thick; V as long 
as III, with a short cylindrical spur about one half the diameter of the 
segment, and scarcely as long as the diameter of this joint at the base. 
Sensoria rather small and inconspicuous, round, one as usual at the 
apex of IV beneath, and one at the base of the spur of V. Eyes distinct, 
contiguous to the prothoracic margin, ocular tubercles feebly elevated, 
with the usual three lenses. Prothorax very indistinctly separated from 
head, but distinctly marked off posteriorly by the deepening of the suture 
on each side and the more rapid widening of the body just behind it. 
Upon the abdominal segments appear traces of four large excretory 
glands on the dorsal surface of each segment. Xo cornicles. Cauda and 
anal plate light yellowish brown, very short and broad, the former at 
the apex of the abdomen, the latter on the ventral surface, not visible 
from above. 

Beneath yellowish, a faint yellowish brown tint between the pos- 
terior legs. Beak short, seldom attaining the middle coxa?, and about as 
long as the antenna?, base and apical half light brownish yellow, extreme 
tip blackish; apical joint about equal in diameter and length to the 
second antennal joint; penultimate joint a little shorter and about equal 
in length and breadth, the lunate marks at its base distinct ; apparent 
basal (second) joint considerably longer than the apical two com- 
bined, and rather slender. Legs light yellowish brown, moderately long, 

* By C. A. Hart. 



87 

the anterior coxae closely embracing the base of the head, the others 
widely separated from each other by the broad flattened meso- and meta- 

sterniini. the middle Legs being nearly as far apart as the posterior pair, 
the anterior about halt' as far. Two distinct claws and two tarsal joints 
on all the legs. Exterior to each leg is an irregular longitudinal spot of 
pale dusky brown, the spots near the anterior legs uniting with those 
un the head which surround the eyes. Spiracles brownish, distinct. 
Seventh segment with a transverse thickened plate at middle beneath, 
light yellowish brown posteriorly. 

Length of body L.8 mm., breadth 1.1 mm., antenna .42 mm. 

Described from two lots of specimens. 

The Kuropean analogue of this species is Tychea phaseoli. 

Geoica squamosa, n. gen. et sp. 

(Plate IX., Pig. 5 and 6; and Plate X., Fig-. 1, 2, and 3.) 

Among the minor aphid insects of the corn plant is a small whitish 
or yellowish mealy 1 species, occurring with ants and in their nests in 
corn fields and elsewhere often enough to attract the attention of any 
close observer of the corn root insects, but never yet numerous enough 
in our observations to do any perceptible harm. 

The following chronological list shows its dates of occurrence in 
our collections, its forms, its food plants, and attendant ants : 
Jan. 20, timothy roots; Lasius; viviparous female. 
Feb. 13, in grass roots; in Lasius colony; oviparous female. 
Mar. 0, sod, by fence, near corn field ; Lasius niger. 

" 21, in last year's corn hill ; burrows of Lasius. 

" 23, in last year's corn hill ; burrows of Lasius. 

" 26, sod; several nests of Lasius niger. 

" 29, sod, along fence between corn field and pasture ; L. niger; eggs. 
Apr. 1, grass roots and a dicotyledonous weed ; large nest Lasius mixtus. 

" 4, roots of shepherd's purse; Lasius niger. 

" 5, breeding cage ; young, from eggs of Mar. 29. 

" 6, on roots of old corn and under boards. 

" 10, roots of shepherd's purse; Formica fusca gagates. 

" 19, grass roots, in meadow ; Lasius niger. 

" 26, in blue-grass sod ; frequent in nests of Lasvus niger. 
May 7, grass ; Lasius nest. 

" 8, timothy roots. 

" 9, roots of young oats in corn ground. 

" 19, sod; Lasius niger. 

" 19, on corn roots in old sod ground, one with beak in root; Lasius 
niger. 

" 21, on corn roots in grass ground; Lasius niger. 

" 21, on corn roots in grass ground. 

" 21, on corn roots, meadow last year ; one killed by mite ; Lasius n iger. 

" 24, on corn roots, grass ground ; Lasius niger. 

" 25, on young grass roots. 

" 28, on corn roots: Lasius niger. 

" 29, on corn roots; Lasius niger. 

" 31. in Lasius nest. 
—7 E 



May 31, corn roots, sod ground; Lasius; pupa, showing wing-pads. 
" 31, in sod; Lasius niger. 
" 31, on blue-grass roots; in Lasius nest; pupge. 
June 1, young corn roots and base of stalk, sod ground, one fourth the 
corn infested. 
" 1, corn roots, sod ground. 

" 5, breeding cage; winged female from pupae of Mar. 31. 
" 6, corn roots, abundant, sod ground; Solenopsis debilis. 
' " 13, corn roots, sod ground. 
July 14, clover roots. 
" 15, on roots of corn. 
" 28-, on roots of corn. 
Aug. 11, on roots of clover (twice). 
Sept. 25, on roots of Panicum crus-galli; Lasius. 
Oct. 15, timothy roots; oviparous female. 
" 20, corn roots. 

" 28, timothy roots; male and viviparous female. 
" 29, in meadow ; Lasius niger; oviparous female. 
Nov. 19, blue-grass and timothy in corn field; oviparous and viviparous 
females and young. 
" 24, corn field ; burrows of Lasius. 
" 24, about roots of corn ; oviparous female. 

We see from the above list that this species has been found on the 
roots of the following plants : 

Corn (seventeen times), Apr. 6, May 19, 21 (three times), 24, 28, 
29, 31, June 1 (twice), 6, 13, July 15, 28, Oct. 20, Nov. 24. Also in 
corn hill of previous year (twice), Mar. 21 and 23. 
Oats, May 9. 

Timothy (five times), Jan. 20, May 8, Oct. 15, 28, Nov. 19. 
Blue-grass (three times), Apr. 26, May 31, Nov. 19. 
Panic-grass (Panicum crus-galli), Sept. 25. 
Grass (five times), Feb. 13, April 1, 19, May 7, 25. 
"Sod" (six times), Mar. 9, 26, 29, May 19, 31, Oct. 29. 
Clover (three times), July 14, and Aug. 11 (twice). 
Shepherd's purse (twice), Apr. 4 and 10. 
A dicotyledonous weed, Apr. 1. 

Thus it is shown that of the forty-seven sets of specimens of this 
species in the collections of the State Laboratory of Natural History 
eighteen were taken from the roots of cultivated plants, twenty-one 
from roots of grasses, three from clover, three from weeds, and two or 
three from ants' burrows but not on plants. 

The fact that it has been found on corn much oftener than on 
other plants does not necessarily mean that it affects this plant to a 
greater extent than others, as in our investigations corn has been ex- 
amined more frequently than the others mentioned. 

It must be noted that this species has been seen but once in a field 
that was not in grass the previous year ; viz., May 9, on roots of oats in 
old corn ground. 

It often occurs in the formicaries of ants with other species of root 
lice, mealy bugs (Dactylopius), and coccinellid larvae. Collections were 
not always made of the ants in attendance, but a careful study of the 



eighteen lots of ants taken in company with this root louse; shows that 
Lasius niger has been so taken fifteen times, and the following species 
once each: Lasius mixtus, Formica fusoa gagates, and Solenopsis debilis. 
During the winter and earl}' spring these lice have been found wandering 
in the burrows of Lasius niger, still guarded and cared Tor by the ants. 

The live known forms of this insect are as follows : the egg, wing- 
less pseudogyne or viviparous female, pupa, winged pseudogyne, and the 
wingless sexed form, consisting of true oviparous females and of males. 
The eggs have been found in spring, from which the young root lice have 
hatched in the first part of April. These are viviparous, and give birth 
to another generation of the same kind, and successive generations fol- 
low during the entire summer. Young have been taken in nearly every 
collection here during the summer months. 

In the fall, usually in October and November, the viviparous form 
gives birth to true sexed individuals, males and oviparous females. These 
copulate and the females lay their eggs in the loose earth around the 
roots of plants in the ant burrows in which they are kept. The ants 
keep these eggs during the winter and spring, and from them in due 
time the young viviparous root lice hatch. Thus the circle of life con- 
tinues. It is shown, however, by our collections that some of the lice 
also live during the winter on the roots of plants, in the formicaries of 
ants, most of these being viviparous and young; but the oviparous 
form sometimes occurs there during the winter or very early part of 
the spring. 

DESCRIPTION.* 

This plant louse is closely allied to certain species commonly placed 
in Tychea, a genus of the Khizobiinse, which is a subfamily whose mem- 
bers have not hitherto been known to acquire wings. A careful study 
of the winged individual bred from a pupa shows that it is a new generic 
type most nearly related to Hormaphis, of the Pemphiginse ; and as 
Tychea seems to contain at least two dissimilar groups of species, whose 
only bond of union is a resemblance in the number and length of the 
antennal joints, it will be well to divide the genus, retaining the old 
name for the typical species, such as phaseoli and brevicornis, and plac- 
ing setarue and its allies together with the present species at the foot of 
the Pemphiginse, as a new genus, for which the name Geoica is now 
proposed. Here also belongs the species" described by Buckton as Endeis 
carnosa, which surely is not an Endeis at all. Tychea panici, Thos., is 
apparently a young Ehizobius. 

geociaj n. gen. 
Antennae 5-jointed. not annulated, first and second joints short, 
third longest, fourth and fifth shorter, subequal, often connate, the fifth 
with a short thick spur at tip. Sensoria present on the third antennal 
joint of the winged individual, and in all of the forms at the apex of 
the fourth joint and base of spur on fifth, the latter sensorium lunate 
in the wingless individuals. Xone present on the tibiae of the oviparous 

* By C. A. Hart. 

f Oe, earth ; oikos, house. 



90 

female. Eyes distinct. Beak rather short and thick, last two joints 
longer than basal portion. Fore wings with the stigma large, the cubital 
simple, obsolete basallv, the two discoidals united at base. Hind wings 
without discoidal vein. Two distinct tarsal joints and two claws on all 
the legs. Anal plate flattened, drawn forward dorsally and compressing 
middle of posterior segments, cauda short, transverse, inconspicuous. 
Cornicles and excretory glands wanting. 

07. squamosa, n. sp. 

Wingless Viviparous Female (Plate IX., Fig. 5 and 6). — Body 
broadly ovate, more or less distinctly and widely margined, sutures dis- 
tinct, surface alutaceous. General color whitish to pale straw-color, cov- 
ered with a mealy excretion. Entire surface, including- antennas and 
legs, with light brown points from which arise sbort thick scale-like 
hairs, the basal half of each erect, but near middle strongly and often 
almost rectangularly bent backwards, the apical half of those on the 
vertex apparently flattened and expanded; a large brush of hairs at tip 
of abdomen. In alcoholic specimens, a varying pattern of dark brown 
longitudinal lines radiating from the cauda, above and below, usually 
four each side of middle, which unite on each side at the base of the ab- 
domen, and often extend upon the thorax as a single stripe; lines usually 
dilated at the sutures. At the base of the abdomen the inner pair di- 
verge; the outer pair are more isolated. A similar marking is some- 
times seen in other species ; it relates perhaps to internal structure. 

Head short, a small brown spot each side of middle, and an indis- 
tinct pale median line. Antennae robust, attaining the side of the meso- 
thorax, usually five-jointed in the adult, but joints III and IV often 
coalesced more or less, the point of union marked hy a distinct constric- 
tion. The apex is faintly fuscous. I and II are subequal, about as long 
as thick, rounded, I very slightly thicker than II, remaining joints 
nearly as thick as II; III longest, nearly or quite as long as I and II 
combined ; IV about as long as II ; V longer, but not as lona: as TIT, 
apical spur short and thick, its diameter nearly half that of the joint, 
and slightly longer than thick, its length being about one fifth the entire 
length of the joint. At the apex of IV is a round sensorium, and at 
the base of the spur of V, and partly encircling it, is a rather large lu- 
nate-reniform one, with a minute one between it and the spur, the lat- 
ter group especially surrounded by dense minute pubescence. Other 
joints without sensovia. Eyes very small, black. 

Prothorax broad, not constricted, with a brown impressed pit at 
the middle of each half dorsally ; remaining body segments with brown 
spots and transverse lines in the sutures, two longitudinal series usually 
distinct, one at the inner limit of the impressed margin, the other about 
one third of the width of the body from each side. No trace of corni- 
cles. Anal plate large, longitudinally oblong, subtruncate at tip, flat- 
toned above, fuscous, strongly retracted among the dorsal segments just 
preceding, and hut slightly projecting behind, the cauda represented 
only by a small transverse plate at base ; preceding two or three seg- 
ments strongly arcuate, brown at middle. 



91 

Beneath, color same as above. Rostrum very robust, yellowish fus- 
cous at base, distal segment fuscous, tip blackish, reaching posterior mar- 
gin of mesothorax. Basal portion less than twice as long as thick, last 
joint a little longer, penultimate half as long as last and about twice as 
thick. Legs, including coxae, yellowish fuscous, with blackish sutures, 
sparsely hairy, moderately long. Thoracic spiracles in dark spots behind 
and exterior to the anterior and middle COX83, abdominal spiracles in a 
row of similar spots on each segment. Below the spiracles is a row of 
dark spots in the sutures, and dark points often occur midway between 
adjacent spiracles. The seventh segment has a transversely oblong 
brown spot at middle as usual. Genital valves brown, often concealed. 

Length 1.!) mm., greatest width 1A mm., antenna .4 mm. 

The young are paler, more elongate, with longer beaks, and clearly 
four-jointed antennae. 

Described from a large series of examples usually taken in ants' 
nests upon the roots of various grasses and other plants, or wandering 
in the galleries. 

Pupa (Plate X.. Fig. 1). — This is very similar in general color- 
markings and vestiture to the viviparous female, but is more elongate. 
The antenna? are as in the viviparous female, and are five-jointed; the 
eyes arc large and well developed, occupying the entire side of the head 
back of the antennae, the posterior tubercle distinct. The head and tho- 
rax are darker than the abdomen, metathorax darker than mesothorax, 
wing-pads also darker towards tips, attaining side of second abdominal 
segment. Prothorax slightly longer than in the viviparous female; ab- 
domen exactly as in that form. Head and first two segments of thorax 
beneath darker than the remaining body segments. 

Length 1.95 mm., breadth 1 mm. 

Desciihed from two specimens, taken May 31 of different years. 

Winged Viviparmts Female (Plate X., Fig. 2 and 3). — The sin- 
gle specimen in our possession is not in good condition, and cannot be 
fully described. The head and thorax are blackish, the abdomen pale, 
with dark spots at the sides of the segments above, and transverse discal 
bands. The antennae are more slender than in the wingless female; 
joints I and II are very short and subequal, III twice as long as I and 
II combined, IV and V equal, the two combined about equal to III, 
spur of V about half as thick as the basal portion, and a little longer 
than thick, subcylindrical. On the lower side of III are eight or nine 
large sensoria arranged in a single row; and two can be seen on V. The 
wings are not large, subcostal vein broad, stigma large, radial vein 
strong, outer two thirds straight, directed a little above the tip of the 
wing, cubital obsolete at base, beginning below middle of stigma. Dis- 
coidal veins united for a short distance at base. Hind wings with but 
a single vein, the discoidals entirely absent. 

Described from one individual, bred about June 5 from a pupa 
taken May 31 from blue-grass roots in a Lasius nest. 

Among material taken in the fall and winter I find two additional 
forms presenting constant differences, and from what I know of the 



92 

forms of related species, I believe them to be the sexed individuals, and 
therefore describe them here. 

Wingless Oviparous Female? — somewhat smaller than the vivip- 
arous female, easily recognized by the absence of the peculiar thick, an- 
gular bent, scale-like hairs which constitute the vestiture of the vivip- 
arous female at all ages, these being replaced by fine short erect hairs, 
straight or nearly so, a little longer and more distinct in younger speci- 
mens. Antennae clearly 4- jointed in all specimens seen. Spots about 
and near spiracles usually well marked. Genital valves distinct in adult. 
No trace of sensoria other than the usual ones on the last two antennal 
joints. Otherwise as in the viviparous female. 

Length 1.85 mm., breadth 1.25 mm. 

Male? — Small, more oval, abdomen less expanded, color as in the 
viviparous female, surface clothed with long erect hairs, less fine and 
more conspicuous than in the supposed oviparous female. Antennae dis- 
tinctly 4-jointed, I and II combined about equal to IV; III a little 
longer. Beak somewhat longer than in the preceding forms. Eows of 
abdominal spots more approximate on each side, hairs of back arranged 
in rows more distinctly than in the young of the form just described. 
Anal plate more projecting, eighth segment more prominent. Other- 
wise not different from the forms already described. Sensoria of last 
two antennal joints as usual. 

Length .8 mm., breadth .41 mm., antenna .28 mm. 

As in related species, a careful search fails to reveal any other 
sensoria, such as those which appear in the sexed individuals of Aphis 
maidiradicis. 

The Woolly Grass Eoot Louse. 

(Rhizobius spicatus, n. sp.) 

(Plate X., Pig. 4.) 

Another grass root louse, belonging to the genus Ehizobius, and 
here described as R. spicatus, has been encountered, occasionally on corn 
in our studies of the insect enemies of that plant. It is representexLjn 
our collections by six lots of specimens, of which one was obtained from 
a corn field at Urbana April 1, a second from grass roots July 20, a 
third from corn roots at Tamaroa, Perry county, October 5, another 
from roots of crab-grass (Panicum proliferum) at the same time, an-» 
other from grass roots October 10, and the last from a corn field Decem- 
ber 5. 

The April and October specimens were adults, except that with 
those taken October 5 were sometimes a few young, — full grown fe- 
males placed singly in small cavities under ground, each being accompa- 
nied by a small group of young. These cavities were at various depths, 
from just below the surface to six inches under ground, and were lined 
with a bluish waxy excretion, doubtless derived from the woolly coat- 
ing of the root lice. 

The July specimens and those brought in December 5 were young, 
the latter about half grown. 



93 

DESCRIPTION.* 

Wingless Vvovpa/rous Female. — Body white or cream color in alco- 
holic specimens, oval or elliptical, covered when alive by a bluish white 
cottony excretion; a few sparse short hairs. 

Head short, subtriangular, narrowly rounded in i'ront. Antennae 
very short, scarcely surpassing the posterior angles of the head, spike- 
like in form, brown or dusky, sutures white. 1 short and thick; II 
equally thick and a little longer, being about as long as thick; diameter 
of remaining joints nearly equal, about two thirds that of II; III 
nearly one half longer than thick; IV a little shorter than thick; V 
somewhat more slender, about as long as III, subconic, with a few very 
short hairs, spur minute, dark brown. No distinct sensoria visible. 
Eyes black, minute, near posterior angles of head. 

Thoracic segments not very short, sides of body sinuate inwardly at 
posterior angles of prothorax. A row of dark brown spots lies near the 
margin on each side of the body, one in each suture. There are also four 
longitudinal rows of dark spots on the dorsum, at about equal distances 
across it, one spot on each segment, usually indistinct. They appear as 
small pale brown spots, consisting of a central brown dot surrounded 
by a fine brown ring. There also sometimes appears a pattern of longi- 
tudinal lines similar to that noted in Geoica squamosa, consisting of six 
lines, grouped in three pairs, the lines of each pair rather near together 
on the abdomen, and diverging on the first abdominal segment, those 
of each side uniting on the thorax into a single band, often absent. No 
trace can be seen of cornicles or tubercles. 

Beneath whitish, beak and legs brownish. Beak short, rather slen- 
der, reaching about half way between fore and middle coxae; last two 
joints about as long as basal portion. Last joint about twice as long as 
thick, tip black. Penultimate joint one half shorter and somewhat wider 
being about as long as broad. Legs short, middle and hind coxrb equidis- 
tant, anterior coxa? about half as far apart. First tarsal joint minute, 
but present; claws two, minute on posterior legs. Venter of abdomen 
marked with a row of indistinct transverse brown spots in the sutures, 
and often with longitudinal darker lines, a pair each side of the median 
line, and another line exterior to these. Spiracles distinct, in minute 
blackish rings. Anterior spiracle slightly elevated. Anal plate ventral, 
not elevated, eighth dorsal segment visible behind it from below; anal 
and genital apertures transverse, brownish. 

Length 1.8 mm., breadth .7 mm., antenna .12 mm. The young are 
broader, with proportionally longer legs. 

Described from six lots of specimens. 

The Chermesinae are doubtless the lowest plant lice and most nearly 
related to the Coccidge. The affinities of Rhizobius seem to be in this 
direction, and it is also closely related to the other Rhizobiinas, most 
of which would probably prove to be Pemphiginae if the winged forms 
were known. It would therefore seem a more natural arrangement to 
place the Rhizobiinse above instead of below the Chermesinae, as it now 
stands, bringing it next to the Pemphiginae. 

* By C. A. Hart. 



94 

Although the species are generally credited with only one tarsal 
joint and one posterior claw, I am inclined to think that a minute first 
tarsal joint of the usual form is really present; and the claws of the 
posterior tarsus, although smaller than the others, seem to be both dis- 
tinctly present in the species here described. 

No winged forms of Ehizobius have ever been reported, yet there 
is in our collections a singular pupa, evidently of this genus but of a 
different species, having well-developed wing-pads. 

Rltizobius pwiici, Thos. (Tychea panici) is closely related to this 
species, but differs distinctly in the antennae and beak. Ehizobius pace, 
Thos., appears to be a Dactylopius. 

The Sorghum Mealy Bug. 

(Dactylopius sorghiellus, Forbes.)* 

(Plate X., Fig. 7 and 8.) 

This mealy bug is an oval, distinctly segmented, reddish or flesh- 
colored insect, covered with a bluish waxy bloom, and commonly bears 
a thicker mass of waxy substance imbedding the bases of a tuft of hairs 
at the tip of the abdomen. It is about .07 inch long, and about as thick 
as wide, its width between a third and a half of its length. It has a 
pair of short, eight-jointed antennae, and a black simple eye on each 
side of the head. 

It is of common occurrence on corn, generally infesting the roots, 
and usually found only where the corn has been planted on sod. It is 
doubtless normally a grass insect. It was first reported by me in 1885 
as a sorghum insect, and described under the name of Coccus sorghiellus 
in my Fourteenth Report as State Entomologist of Illinois (p. 71). It 
has since been found by us on corn (roots, leaf sheath, and leaf), on 
sorghum (August 4), and on the roots of June grass, timothy, and prob- 
ably other meadow and pasture grasses, clover, and cocklebur (Xanihium 
strumarium). It is commonly attended by ants, especially the species 
most frequently acting as host to the corn root aphis, Lasius niger and 
its variety alienus. It sometimes passes the winter in their nests, where 
we have seen ants feeding on the waxy surface-covering of the mealy 



Its methods of multiplication are similar to those of the plant lice, 
viviparous females producing young in spring, and a sexual oviparous 
generation appearing in fall. We have found adults in the earth on the 
roots of grass (timothy) March 24, and have collected them from earth, 
among the roots of clover, May 14. May 15 we have taken them from 
the roots of young corn with the small brown ant Lasius niger alienus 
in attendance, and May 17 have seen adults and half -grown young to- 
gether in the same situation. The young thus seem to make their first 
appearance for the year in the early part of May. May 18 and 19 many 
specimens were obtained on corn roots at Champaign, and at Polo in 
northern Illinois, those at the former place rapidly producing young by 
viviparous generation. These were at this time scattering over the corn 
plant, and were most abundant in the youngest folded leaves. This 

* Coccus sorghiellus, Forbes, Fourteenth Rep. State Ent. 111. p. 71. 



95 

mealy bug has also been collected by us May 20 at Mendota, and May 
21, 24, 28, 30, and 31 at Champaign, adults and young occurring on 
both corn and grass (pasture sod), usually with the above-mentioned 
ant in charge. June 5 it was found on June grass, behind the ensheath- 
Lng part of the leaf, and the 6th and 16th on corn roots again, and the 
loth on the roots of young cocklebur in a corn field — here, also, in 
charge of Lasius ullc/tiis. Our remaining collections — one in duly, three 
in August, and two in October — all contained adults, those tor October 
either eggs or young also. October 20 a single reddish brown female, 
with legs of a similar color, was found on the outer surface of a corn- 
leaf sheath about four inches from the ground, surrounded by a little 
speck of iloceuleiit material containing many eggs. October 25 adults 
and young— -whether oviparous or viviparous does not appear from our 
notes — were taken together in old pasture ground near Champaign, 
attended by the two common ants mentioned above. No males of this 
species have yet been recognized. 

DESCRIPTION. 

The body is oval, distinctly segmented, .07 of an inch long by .027 
inch wide, and .024 inch deep. The surface is covered by a bluish 
bloom, and a waxy mass imbedding the bases of a cluster of long hairs 
commonly adheres to the anal extremity. The antenna? are short, reach- 
ing to the coxae of the first pair of legs, and distinctly eight- jointed, the 
first two joints thick (the first much the thicker) and about equal in 
length, the third as long as the second but narrower, the fourth the 
-hortest of all, and about as wide as long. Each of the following joints 
is slightly larger and longer than the preceding, and the eighth is 
enlarged to a kind of club, as wide as the second joint and very nearly 
as long as the sixth and seventh together. The rostrum is very short, 
two-jointed, conical, 'projecting from between the bases of the first pair 
of legs. It is not as long as the femur, and its width is about half its 
length. The maxillary filaments are four in number, and when extended 
reach the abdomen. The eyes are placed upon the sides of the head at 
a distance behind the bases of the antennas about equal to the first joint 
of the latter. They are black and simple, each consisting of a single 
ocellus. The tarsi are all 1-jointed, two thirds as long as the tibiae, and 
tapering regularly to the claw. This is strongly curved, with a pair of 
slender capitate hairs, longer than the claw itself, springing from its 
base. The tibiae and the femora are of about equal length; the antennas 
and legs are slightly hairy, and the body nearly smooth, only a few 
minute hairs being scattered over the surface. There are also a few 
long hairs at the tip of the abdomen. The latter is two-lobed and 
emarginate, with a small cauda at the base of the emargination, slightly 
blackish distally. This emargination becomes a cup-shaped depression 
when seen from behind. 

Egg. — Oval-oblong, subcylindrical, about twice as long as thick, 
brownish, surface smooth and shining. 

Length .30 mm., width .16 mm. 



9G 



2. Boots evidently injured or destroyed by perforations, gnawing, bur- 
rowing, decay, or other loss of substance. 
a. Eoots eaten away, not burrowed or perforated, and without 
rotten or withered tips. Tap-root commonly gone or de- 
cayed. White grubs in soil among or beneath the roots. 

THE WHITE GEUBS. 

GENERA LACHNOSTERNA AND CyCLOCEPIIALA. 
(Plate XII., Fig. 1-8; and Plate XIII., Fig. 1 and 2.) 

White grubs or "grub worms" are among the immemorial enemies 
of agriculture on both sides of the Atlantic, and in both Europe and 
America the problem presented by their injuries on the farm and in the 
fruit and vegetable garden still calls for throughgoing investigation 
and scientific treatment. In fact, the steady increase of their numbers 
in this State— probably connected with the gradual enlargement of the 
area laid down in grass — has made such an investigation of their life 
histories, habits, and economic relations simply imperative and indis- 
pensable. 

They infest a great variety of plants, nearly all of which have an 
agricultural value, many of them being the great staple crops of the 
farm and garden. Grasses of every kind, all the small grains, Indian 
corn, potatoes, beets, and the root crops generally are liable to destruc- 
tion by them, as well as strawberries and young fruit trees, young ever- 
greens, larches, and young forest trees of various kinds. 

Like most other injurious insects of the first class, they are liable 
to great variation and fluctuation of numbers in different localities and 
in successive years, sometimes getting the temporary mastery of a con- 
siderable tract, appropriating nearly its whole growth of vegetation to 
their own use, and then, within a year or two, disappearing from view 
for a time as an injurious agency. Apart from these seemingly spon- 
taneous fluctuations of numbers, they are most likely to cause great 
loss when the crop on ground infested by them is changed by rotation 
from one affording them an abundance of food to one yielding a rela- 
tively scanty growth — as when grass lands are planted to corn. A num- 
ber of grubs which would produce no visible effect in a dense sward, may 
be sufficient to devour completely a field of young corn. 

They hatch most commonly in grass lands (although frequently 
also in corn), from eggs laid there by various kinds of beetles, all com- 
monly confused under the general name of "June beetles" or "May 
beetles" or "dor-bugs." These large, thick, short, snuff-brown beetles, a 
half inch to more than three fourths of an inch in length, nearly as 
thick from above downwards as they are wide, and about half as wide 
as long, are universally known because of their great abundance in May 
and June, during which months they fly at night, filling the air at dusk 



97 

with their hoarse buzzing, and often invading lighted rooms in our 
houses, where they bump and bumble about, as awkward as frolicking 
cart horses. In this stage the insects are but short-lived, the males dying 
soon after the sexes pair, and the females living but a few days after 
they have laid their eggs in the ground. 

The young grubs hatching among the roots of grass or grass-like 
plants commence to feed at once, and live in the earth in the larval stage 
for at least two years (so Jar as known), most of them changing to the 
dormant pupa from the middle of June to September of the second or 
third year after hatching, and becoming fully developed "June beetles" 
again, still in the earth, in August or in September of this same year. 
These beetles' fto not, as a rule, emerge from their earthen cells until the 
following spring, but spend the winter at rest, each in the underground 
cavity made originally by the grub while preparing to pupate. In May 
and dune they come out and pair and lay their eggs as already related. 
A single species (Cyclocephala immaculate/,) has a slightly different life 
history, the grub not pupating until spring. 

Our common and destructive white grubs all belong to the genera 
Lachnosterna and Cyclocephala, by far the greater number of species and 
individuals to the former genus, of which there are thirty-two species 
known to occur in Illinois. The genus Cyclocephala, on the other hand, 
contains but one species in this State. The life histories of these various 
kinds are not sufficiently different to make discrimination of species a 
matter of practical importance, and for economic purposes, consequently, 
the white grubs may usually be classed as one. 

No wholly, or even fairly, satisfactory defence against them has yet 
been discovered, but in the contest with so abundant, so widespread, and 
so destructive' an insect even imperfectly protective measures, or merely 
palliative ones, are worthy of the most careful attention. The practice 
of the farmers of the Old World, where a contest against closely related 
insects of like habit has been waged from time immemorial, is not usually 
applicable to American agriculture, but may nevertheless become so as 
conditions gradually change with the denser settlement of this country 
and a corresponding increase in the value of our agricultural products. 
I have consequently summarized the economic procedure of England, 
France, and Germany for the "cockchafer grub," the "ver blanc" and 
the "engerling," — the names by which the European "white grubs" are 
known in those countries respectively. 

INJURIES TO CORN AND OTHER VEGETATION. 

The injuries of the American 'white grubs to corn may begin as 
soon as the roots of the young plant become large enough to attract the 
attention of a hungry insect, and may range — according to the age of 
the plant, the kind of weather, and the age and abundance of the grubs 
— all the way from a slight and temporary retardation of growth to an 
immediate and complete destruction of all the corn. An early loss of the 
tap root exposes the plant to severe suffering by early drouth, and it is 
often so reduced in vigor from root injury that it fails to form brace 
roots at the proper time, and hence has so slight a hold upon the earth 



98 

that it cannot keep itself erect or recover itself after prostration by a 
windy summer storm. 

In any case where the plant is yellowed, or dwarfed, or killed out- 
right, — especially if these appearances be most marked on the higher, 
lighter parts of the field, — the presence of white grubs may be sus- 
pected. 

As the roots of an infested plant are evidently eaten away, injury 
by the white grub is not easily mistaken for any other, and the presence 
of the conspicuous insects themselves, in the earth among or beneath the 
roots, will commonly confirm the diagnosis. If they are not thus found 
where other evidence points to them as the cause of the injury, they may 
frequently be discovered by digging down a foot or two in the worst- 
injured tracts. 

As a fair illustration of the extent and general effect of a severe 
attack on corn, our observations of their work in a twenty-acre field near 
Champaign, Illinois, are worthy of detailed report. This field of rich, 
black land had been heavily fertilized with straw-pile manure and 
seeded to timothy in 1884. It was pastured continuously until 1888, 
when it was left for hay, yielding a good crop of clean timothy that year. 
The sod was broken in the spring of 1889, and planted to corn May 10, 
immediately after breaking. This first planting was taken by web 
worms and cutworms, but the second grew well, and promised an excel- 
lent crop until about tasseling time, when the owner noticed that much 
of the corn had a yellowish and unhealthy appearance, and that it blew 
down readily when the ground was wet. These fallen hills pulled up 
easily, and the roots had a stubbed appearance, as if cut off near their 
origin. A search in the earth where the corn had stood commonly 
yielded six to twelve white grubs to a hill. The crop on two or three 
acres of the highest land was a total failure, and the yield was light on 
the lower ground. 

The following year (1890) the field was plowed April 28 and 
planted again to corn, although an abundance of grubs were noticed when 
the plowing was done. Several hundred were, in fact, collected by us 
April 28 for breeding-cage experiments, nearly all belonging to the species 
L. rur/osa. An estimate based at this time on a count of the grubs found 
within the length of a rod in a fourteen-inch furrow, gave between six 
and seven hundred to the square rod, or at the rate of two hundred and 
eighty-eight pounds per acre. By the time the young corn was six inches 
high about two thirds of it had been destroyed by the grubs. The field 
was not replanted, but about the 10th of June it was twice harrowed and 
sown to hemp. On account of the lateness of the season and a mid- 
summer drouth the hemp did not grow well, and about a hundred bush- 
els of corn were finally taken from this twenty-acre field. July 26, in 
the part of the field which had been worst infested, but three grubs and a 
single pupa were found in digging with a spade twenty holes, ranging 
in depth from a foot to twenty-six inches. On the 1st of September a 
trench four feet long, three feet wide, and two feet dee]) was dug in 
this same part with the result that only one adult June beetle and two 
long-dead larva? were found. In another space eight feet long by three 



99 

feet wide two adults and a single living larva were dug out, all the fore- 
going being within a foot of the surface. In two large areas turned 
over at the margin of the worst-infested spot, two living larvae and one 
adult were taken, the former among the corn roots and the latter about 
ten inches down. 

From these field observations, and parallel extensive breeding op- 
erations in the insectary, we have reason to infer the transformation to 
the imago stage during the season of 1890 of the greater part of the 
white grubs in the ground. 

In 1891 the entire field was sown to hemp; hut in 1892, three 
years after breaking, it was planted again to corn, and again heavily in- 
jured by grubs. August 25, a general survey of the field showed that 
no part was free from them, and that probably every acre had been in- 
jured more or less. The damage was most serious now on the lower 
ground, where a tract of about two acres bore only a few scattered stalks 
with ears. Most of the corn here had failed to tassel, and much of it 
had died when from eight or ten inches to about three feet high. Patches 
of a rod to two or three rods across on which the corn was dead or worth- 
less were to be found in all parts of the field. Nearly all the foxtail- 
grass (Setaria) had also been killed, the roots being cut off just below 
the surface, and even the common purslane (Portulaca) was similarly 
destroyed. Most of the grubs were at this time within three inches of 
the surface, and were well scattered through the ground, being by no 
means confined to the hills of corn. In one selected area of four feet 
square, which included only two corn hills, eighty-one grubs ^v^ve dug 
up, some scarcely beneath the surface, and none deeper than three inches. 
In another area of equal size, containing three corn hills, one hundred 
and thirty-six grubs were found, twenty-one of them in a single hill. 
Here, however, a few had burrowed to a depth of six inches. The grubs 
were at this time apparently from two-thirds to three-fourths grown, 
the most abundant species being L. rugosa— the same as that of the pre- 
vious years. 

In addition to affording an excellent illustration of the destructive 
capacity of the common white grubs, this record is of special interest as 
evidence that L. rugosa at least will lay its eggs and breed abundantly 
in fields of corn. On no other supposition can we explain the appear- 
ance of such vast numbers of partly grown larva? three years after the 
ground was broken from grass in the spring; three years, that is, sub- 
sequent to the latest time at which the eggs could possibly have been 
laid in the grass. It seems very likely that this second lot of grubs 
was hatched from eggs laid in the corn in the summer of 1890 by the 
beetles which came out of the ground in this same field. If this infer- 
ence be correct, it follows that planting to hemp for a year will not clear 
the gBound of grubs. 

A somewhat .similar inference of a readiness to breed in corn is to 
be drawn from our observations on another plot of about four acres on 
the University farm near Urbana. This field, broken up in the spring 
of 1890 and put into corn, was planted in 1891 partlv to corn, and 
partly to oats : in 1892 to oats and corn again, but with the areas re- 



100 

versed; and in 1893 to corn. On this the third year from sod, more 
than half the corn fell flat on the ground by the middle of September, 
most of the roots being eaten off by white grubs, of which three or four 
were commonly to be found in a hill. Owing to the consequent weak- 
ening of the plant the brace roots failed to form, the ears which set were 
small and very often imperfect, and a large percentage of the stalks 
were barren, the total height of the plant varying from six or eight feet 
to less than a foot. Even the tallest stalks were slender and unhealthy 
in appearance, the lower leaves, and sometimes practically the entire 
foliage of the plant, being as dry and brittle as in midwinter. Those 
stalks which had been killed early were usually so decayed as to be 
readily pulled apart at the nodes. 

From these data we must conclude that the species concerned — 
which was either inversa or fusca — may live as a larva through four full 
years, making the entire life history cover a five-year period, or else 
that the eggs were laid later than 1889 in either corn or oats. 

The white grubs taken by us in corn fields under circumstances to 
satisfy us that they either were or had been feeding on the roots of 
corn belong to eight species, as follows : Lachnosterna fusca, tristis, in- 
versa, hirticida, rugosa, gibbosa, and ilicis, and Cyclocephala immacu- 
lata. Of these L. fusca, inversa, and rugosa are much more common 
in such situations; and to them by far the greater part of the damage 
done to corn by the white grubs in central Illinois must be attributed. 

Next to Indian corn, the crop most generally and seriously in- 
jured in Illinois by grubs is grass ; and here the loss is the more serious 
because continuous and usually unnoticed. A very large number of 
these insects may live their long lives in the sod, feeding steadily at the 
roots, and thus diminishing the yield without actually deadening any 
continuous area. It is only when through uninterrupted multiplication 
they become excessively abundant, or when severe drouth checks the 
growth of vegetation, that brown patches may appear in midsummer, 
sometimes merging in areas of an acre or more over which the turf, 
loosened by a destruction of its roots, may be rolled up like a carpet. 

That they Avere original inhabitants of the wild prairie sod is shown 
by the common testimony of old settlers, and by Walsh in the "Prac- 
tical Entomologist" (Vol. I., p. 60), where he reports that in 1845 
he found white grubs eating off young corn when it was a foot in height, 
in a field broken from prairie land the preceding year. 

Patches of wheat, barley, and other small grains may be similarly 
killed, all underground parts of the plant being completely eaten up; 
but clover is scarcely ever damaged to any considerable degree, and 
grubs are relatively rare in clover sod mixed with grass. Their injuries 
to potatoes have often been reported, and are generally well known, and 
they are among the worst insect enemies of the strawberry grower. In 
regions where the sugar beet is an important crop, they are among 
the chief injurious insects to be taken into account. Young larches 
and evergreens are sometimes killed by them in the nursery rows, and 
probably every kind of delicately rooted shrub and of young fruit and 
forest tree is liable to destruction by them. 



101 

No general list of their food plants has ever been prepared and 
nothing whatever is known of preferences with respect to food among 
the different species of grubs. Thai the] may live for a considerable 

period on earth alone is shown by Dr. Riley, who says that he has 
known the larv;v of the common May beetle to Iced \\>v three months 
upon nothing but pure soil r : and Professor Perkins, of Vermont, has 
ke|>t individuals of all ages alive for weeks, and sometimes for months, 
in sand more free from organic matter than the soil of any field fit for 
growing crops. f The remarkable tact that the grubs may eat locust 
eggs in the ground has been mentioned in the First Reporl of the U. S. 
Entomological Commission (p. 305). 

The beetles of the white grub feed most frequently on the leaves of 
various species of trees. Oak, hickory, ash, box-elder, elm, chestnut, 
butternut, black walnut, basswood, hackberry, hazel, willow, black lo- 
cust, mountain ash, tame and wild cherry, and pear are the species posi- 
tively known by us, by personal observation, to be eaten by the adult 
beetles of various species; and apple, plum, Lombardy poplar, sweet 
gum (Liquidambar), maple, and birch may be added to the list on other 
authority. When a tree is much infested, the leaves are eaten entire 
except perhaps a stub of the petiole, or the petiole and a part of the 
midrib. Even the bark of the younger twigs may be gnawed away. Two 
species, hirticula and fused, have been charged with an almost wanton 
injury to the foliage of trees (oak and chestnut) done by gnawing 
through the leaf petioles without eating the leaves (Proc. Ent. Soc, 
Washington, Vol. II., p. 59), and we have noted the same habit as occa- 
sionally exhibited to some small extent in the "artificial forest" on the 
University premises at Champaign. The imagos sometimes eat the 
leaves of blue-grass also, and we have once found them feeding on 
heads of clover and once on corn. Several species have been known to 
eat the leaves of raspberries ("Insect Life," Vol. I., p. 366). 

Concerning the food of the separate species, we have only notes 
on the preferences of L. inversa, L. hirticula, and L. fusca. In our 
breeding cages we learned that adults of L. inversa would feed upon the 
blades of blue-grass, at least when nothing else was available, and that, 
supplied with leaves from a variety of trees, they ate freely of oak, elm, 
and chestnut, and slightly of hazel, but neglected ash. L. hirticula also 
ate blue-grass in our breeding cages under similar circumstances, and 
devoured chestnut very freely, but at first did not touch ash or oak. 
Later it ate elm, oak, and chestnut greedily, hazel and hickory sparingly, 
and birch not at all. Oak and chestnut leaves seem, on the whole, to be 
the favorite food of this species. L. fusca, similarly fed, also ate oak 
and chestnut greedily, and ash and elm less freely. A single species 
(L. rubiginosa) has been reported to eat "New Jersey tea" (Ceanothus 
am&rioanus) in Kansas. J 

These notes on the food of the beetles are of interest because of the 
damage sometimes done by these insects, especially to trees on lawns, dur- 
ing the brief period of their excessive abundance in May and June, but 
still more because it is in the adult stage that the white grubs are most 

* St. Louis "Globe-Democrat," March 25, 1876. 

t Fifth Ann. Rep. Vermont Art. Exper. Station (1891), p. 151. 

% Proc. Ent. Soc. of Washington, Vol. II., p. 244. 



102 

susceptible to organized attack. If they are ever thoroughly mastered 
by the farmers of America, it will apparently be by concerted measures, 
possibly supplemented by legal requirement, for the destruction of June 
beetles before they have laid their eggs. 

The food of the larva of Cyclocephala does not differ from that of 
the common species of Lachnosterna so far as our observations go, the 
Cyclocephala grub having been taken by us from grass and from corn. 
The food of the imago of G. immaoulata is not known to me. Specimens 
of this insect enclosed June 23 in a breeding cage with branches of 
basswood, ash, birch, oak, elm, hard maple, and soft maple, began to die 
on the 25th, and had all died by July 2 without eating anything. 

LIFE HISTORY AND HABITS. 

Lachnosterna. Imago (Plate XII., Fig. 1, -1, and 6). — The adult 
beetles of the genus Lachnosterna, hibernating in the earth in the cells 
where they originated, emerge in spring and early summer at periods 
varying according to the species of beetle, the general advancement of 
the season, and the character of the weather at the time. Warm and 
genial days in spring often bring them suddenly out in myriads where 
previously only scattered individuals have been seen, and their flight at 
night is of course more free when the weather is warm than when their 
energies are chilled by cold and storms. 

In Central Illinois L. fwsca is usually the earliest to appear, com- 
mencing to emerge as early as April 12, and continuing alive to June 
4. Inversa and hirticnla are likely to follow a few days thereafter*, 
and trisiis, usually a woodland species, at about the same time (May 7 
with us to June 7). L. gibbosa is relatively late, our earliest specimens 
having been taken May 14, and our latest June 25 ; and L. rugosa later 
still — the latest, in fact, of all our very abundant species, ranging from 
May 18 in our collections to July 28, at which latter date specimens 
were taken flying at night in Northern Illinois. July 16, an imago of 
this species was observed in Champaign county feeding on a leaf of 
corn in the field. L. crenulata appears in Illinois in July and August, 
and, according to Dr. Riley, L. ephiUda is also a late species, occurring 
in the same months. (Proc. Ent. Soc. Washington, Vol. II., p. 133.) . 

As a rule, the males are not only the first to appear but surpass 
the females in number, taking the season through. They also come to 
lights much more freely than the females, as is shown by a comparison 
of our collections made at lights with those made the same night from 
trees on which the beetles were feeding. The 7th of May, 1891, for 
example, a collection of L. Inversa made with a lantern trap contained 
1,210 males and twenty-four females, — a ratio of fifty to one, — while 
we took from trees the same night one hundred and twenty-two males 
and seventy-three females — less than two to one. Taking all our collec- 
tions of this species for the summer of 1891, we find that in those from 
lights (1,418 specimens) the males are to the females as fifty-one to 
one, while in those from trees (271 specimens) the ratio was one and 
one half to one. This is, however, much greater than the usual differ- 
ence in other Lachnosternas, the species evidently varying with reference 

* April 29 is our earliest date for each, and June 24 is our latest for Mrticula 
and June 28 for inversa. 



103 



to their sensibility to light. L. j'usnt, gave us on the date first men- 
tioned, May 7, less than two males to one female (1.6 to 1) at the lan- 
tern trap, while for tristis the ratio was 1.4 to 1 (79 and 56). L. hir- 
liciiln seems to be an intermediate species in this respect. Of 537 speci- 
mens discriminated as to sew L52 males and 33 females were taken at 
lights (nearly 5 to 1) and 194 "males and 158 females on trees (about 
1.8 to 1). 

However taken and at whatever part of the season, it is rarely that 
the females exceed or even equal the males in the same collection. 
Throwing together 2,600 specimens of several species, taken at frequent 
intervals throughout the season of 1891, the sexes of which wc have 
separated, it appears that the ratio of males to females at lights was 
16.5 to 1, and from trees and various surface shelters (839 specimens) 
^.'^ to 1. My data on this subject may be conveniently exhibited in the 
following tabular form : 





Dates. 


At Light. 


On Trees, etc. 


Species. 


No. of 

Specimens. 


Ratio of male 
to female. 


No. of 
Specimens. 


Ratio of male 
to female. 




Apr. 18— June 4 
Apr. 29— June 24 
Apr. 29— June 28 

May 7 

May 15— June 24 


94 

185 

1,418 

135 

42 


2.2 

4.6 
51.0 

1.4 
13.0 


193 
352 
271 

20 


1.3 




1.3 




1.5 








2.3 







The adult beetles emerging from the ground, flying about at night* 
in search of food, pair in the trees, to which they resort in myriads, 
and retreat again to the earth, by day. Their first flight is made in the 
early evening, beginning at dusk, as they pass from the ground where 
they have lain hidden by day to the trees on which they feed. With 
the advent of day they fly from the treesi to the earth, and hide them- 
selves an inch or less under ground, or sometimes merely creep under 
fallen grass and other similar shelter. 

Particulars concerning this retreat to their hiding places at the 
dawn of day are given in notes made by Mr. John Marten and Mr. 
Philip Hucke, detailed for night-work on June beetles May 19, 1891. 

3 :4o a. m. Mr. Hucke reports the occasional dropping of a beetle 
from trees in the artificial forest (chiefly butternuts and hickories) 
where these observations were made. At 4 : 05, an occasional beetle still 
dropping to the ground without making any effort to fly. At 4:10 the 
air suddenly becarfte full of flying beetles. One and then another be- 
gan to make a buzzing noise with its wings, when, as if at a general sig- 
nal, they deserted the trees in thousands, and by 4: 25 everything was 
still again and nearly every one was gone. 

Within the woods the beetles flew to a distance from the trees about 
equal to the height from which they started, the lower ones on the trees 
making a somewhat longer flight proportionally. Striking against the 
weeds and undergrowth, they folded their wings, and by 4 : 30 o'clock 
reached the ground within a hundred feet of the trees from which they 



* A single species has been observed to fly by day in Utah. 
Wash., Vol. II., p. 241.) 
—8 E 



(Proc. Ent. Soc. 



104 

took their flight. Probably in a clearer place they would make longer 
flights. 

The Egg. — Some of the species begin to lay their eggs in the earth 
early in June, and this operation is in progress for about a month. The 
eggs are placed from an inch to three inches beneath the surface, each 
enclosed separately in a cavity just large* enough to hold it, several, how- 
ever, being frequently placed near each other, but never, according to 
our observations, in a common cell. There appears in no case any spe- 
cial preparation of the soil or chamber containing the egg, the statement 
commonly made to the effect that the eggs are laid in a ball of earth be- 
ing clearly erroneous. The eggs are oblong-oval when first deposited, 
but soon swell by absorption to a nearly spherical form. The males be- 
gin to die not long after pairing, and the females also perish as their 
ovaries are spent. The eggs hatch in from ten to eighteen days, ac- 
cording to our experiments. As the data upon which these statements 
are based are few, they may profitably be given in some detail. 

Our earliest observations on this subject were made June 28, 1889, 
when some transparent white eggs were found among the roots of corn 
on the University premises, about an inch and a half below the sur- 
face. The ground was quite free from weeds and grass. These eggs, 
kept in earth in a breeding cage, hatched July 11 as unmistakable white 
grubs, but whether of the genus Lachnosterna or Cyclocephala it is not 
now possible to say. In 1890. thirty-seven specimens of L. in/versa ob- 
tained from the earth by following the plow in corn fields and grass 
lands at various dates from April 2 to 29 were confined in a breeding 
cage with an abundance of sod. On the 8th of May three of these 
beetles had emerged from the earth in the breeding cage, and they were 
thereafter fed with leaves of oak, elm, and chestnut, all of which they 
freely ate. By the 17th of the month the abdomens of the female were 
much swollen and full of well-developed eggs, as determined by dissec- 
tion, but no eggs were to be found as yet in the earth. May 26 and 
31 and June 4 a thorough search of the cage showed that oviposition 
had not yet begun, but on the 5th of June half a dozen eggs were de- 
posited, and next day many were found, each in its separate cavit} r , as 
above described. Males began to die June 6, in this breeding cage, and 
the first female died on the 14th of June, her ovaries being spent, as 
shown by dissection. No eggs had hatched June 21, although those iso- 
lated for observation were advanced in development, showing the out- 
lines of the larva within. On the 23d the first one hatched, and re- 
cently extruded eggs were also found ; and on the 28th the breeding 
cage still contained, besides young grubs, well-developed eggs apparently 
about to disclose the young. The beetles had in fact not yet all perished, 
although those alive were sluggish and apparently about to die. 

The next year (1891) beetles (L. inversa) collected May 18 and 
19 at lights and from the earth were placed in a barrel of earth, itself 
sunk into the ground, and eggs were obtained June 1, deposited singly 
as before. 

A similar experiment with adults of L. hiriicula was started April 
8, 1890, and here also the first two beetles emerged the 8th of May. 
On the 25th of June no eggs were to be found, but on the 28th eggs 
were first discovered — of a shape to indicate their recent extrusion. 



105 

Xine of those were isolated, and from them larvae hatched on the 7th of 
.July. 

May s. L891, both s.-xes of this species were confined in a barrel 

o!' earth sunk in the ground and planted to corn, the I ties being sup- 
plied with elm leaves as food. They deposited eggs June ."> from two to 
three inches below the surface, hut the enclosure being invaded by a 
parasitic fungus (Sporotrichum), the experiment came to an end before 
the eggs had hatched. 

Observations on Lachnosterna fusca are closely parallel to the fore- 
going. Beetles to the number of twenty-eight, collected from the earth 
in corn fields and in sod from April 8 to 28, were placed in the insec- 
tary, where they commenced to emerge May 1, but began almost at once 
to die. They were \'cd, as above, on oak, ash, chestnut, and elm, pre- 
ferring the oak and the elm. On the -fth of June two beetles were 
found in cavities in the earth below the sod, one of them with a freshly 
laid egg just under the abdomen. Fungous disease appearing in this lot 
of beetles interrupted the experiment. May 8, 1891, a large number of 
beetles of L. fusca caught at a lamp or dug from the -earth were used 
for a similar experiment. June 1 oviposition began, the eggs being 
deposited about two inches below the surface, among the corn roots in 
the breeding cage, singly, as before, without special preparation of the 
cavity for their reception. 

A similar trial with L. rugosa, taken from earth and weeds at Ur- 
bana June 1, 1891, gave us the eggs June 11, disposed singly about an 
inch below the surface ; and in another, with L. gibbosa collected May 
20, the eggs were found June 5 about three inches below the surface in 
the loose earth of the breeding cage, placed .separately, but clustered 
somewhat, three to six in a group. 

The eggs of all these species agreed in color, shape, and general ap- 
pearance with those obtained from L. inversa, as described above. 

Larval Period. — Our knowledge of the length of life of the white 
grubs in the larval stage is based solely upon inferences mostly, drawn 
from the varying sizes of the grubs that appear in collections made at 
any given time. Since the eggs are all deposited practically within a 
month, and since the larva grows but slowly, differences in size due to 
variations in time of hatching must be but small. It is easily seen, bow- 
ever, from almost any large collection made in spring or early sum- 
mer at one time and place that grubs of the same species or group can 
be readily assorted into two lots differing notably in size, and never, so 
far as my observation goes, into more than two.* This is readily to be 
explained on the supposition that the larger specimens are two years old 
that season and that the smaller have hatched from eggs laid the preced- 
ing summer. Upon this supposition the Lachnosterna larva lives as a 
grub a trifle over two full years, changes to the pupa and imago at the 
beginning of the third year of its life, and emerges from the earth an 
adult, prepared to lay its eggs, at the end of this three-year period. 

The growing grubs feed, of course, only during the season of 
growing vegetation, usually retiring from the middle to the last of No- 

* To verify this statement it is necessary that the observer should learn to dis- 
tinguish species, or at least groups of species, of these insects in the grub and larval 
stag-e, characters for which are given further on in this treatise. Adult grubs of 
some of the smaller species might otherwise be mistaken for young of the larger 
ones. 



106 

vember to a depth beneath the surface varying according to the severity 
of the winter weather, and coming up again within reach of food com- 
monly some time in March or early April. 

The time and place of hibernation have their especial economic in- 
terest, since while in their usual winter quarters the white grubs are 
far beyond the reach of any agricultural operations. The distance to 
which they retreat in this latitude is about a foot and a half, if I may 
judge from a single observation made November 29, 1886, in a badly 
infested field of wheat in Sangamon county, Illinois. Here, around the 
margins of denuded patches, — the ground being frozen some four inches 
deep, — the white grubs were found repeatedly in numbers averaging 
four or five to the square foot at a depth varying from a foot and a 
half to two feet. In 1890 they had already come up, in the pastures, 
from their winter quarters by the 21th of March; were still at the 
surface in their usual number during the latter part of October; and 
had not wholly withdrawn by November 25 — although at this late date 
most had gone beyond the reach of the plow. Notwithstanding this 
well-marked habit of retreat at the approach of winter, they occa- 
sionally linger at the surface" and hibernate at a depth scarcely greater 
than that at which they are to be found during the summer season. 

Pupation and Formation of the Beetle. — The full-grown white 
grubs, presumed to be two years old according to the preceding section, 
will live an active life in the earth, feeding freely from March to June 
or July, during which months they change to the pupa a few inches 
under ground, in oval cells made by the grub by turning about in the 
earth. In this smooth-walled chamber the cuticular remnant of the 
last moult will be found enclosed with the pupa — that is, the crust of 
the head of the grub and shriveled fragments of its last skin. Our 
first date for this pupal transformation of L. inversa is June 13, 1889, 
but Professor Perkins notes* the pupation of two larva? out of several 
hundred early in May.f In this chamber they lie until August or Sep- 
tember, when they change to the June beetle, fusca and gibbosa as early 
as August 11, and others— at least individuals of implicita, for ex- 
ample — not before September 17. A small percentage of the adults 
thus formed late in the summer and in early fall, may escape from 
the earth before the winter opens, but this is relatively a rare occur- 
rence, the great mass of the generation continuing through the winter 
in the pupal cells within which they originated. They are to be found 
in winter from no more than two or three inches to about ten inches be- 
Ineath the surface. Hence they escape in spring, as already described, 
pairing and laying their eggs for the generation following. 

From the foregoing it will be seen that the white grubs of the 
genus Lachnosterna hibernate in two stages only, those of larva and 
imago, the grubs themselves representing at least two generations. \ 

♦Fifth Ann. Rep. Vt. Agr. Exper. Station (1891), p. 148. 

t From the fact that the grub of Cycloeephala pupates in May in Illinois. I 
surmise that the above-mentioned larva; belong to this genus, and were not dis- 
tinguished from the Lachnosterna larvae among which they occurred. 

% For the full particulars upon which the foregoing statement is based, see 
Seventeenth Rep. State Ent. 111., pp. 31-38. To the data there tabulated, I may add 
the following items noted in 1891 : Grubs of L. fusca collected in corn fields near 
Champaign, April 16 and 17 and May 2, had begun to pupate July 18; and those 
of L. rugosa, taken at the same times and places, had formed two pupa? at this last 
date just mentioned. 



107 

Cyclocephala (Plate XII., Pig. 8; Plate XIII., Fig. 1 and 2).— 
The white grubs of the genus Cyclocephala differ from those of the 
various species of Lachnosterna in so Ear, at least, as to hibernate in 
the Larva] Btage only, to pupate in May ami June, and to emerge as beetles 
in June and July — later on an average than the species of the other 
genus. Pupation is consequently earlier than in Lachnosterna, and the 
emergence of the imago occurs later in the season, the essential difference 
being that adults of Cyclocephala escape from the earth one or two 
months alter the completion of their Larva] Life, while those of Lach- 
nosterna continue in the earthen cells as pupa' and imagos about ten 
months. The difference in the economic application of these biographies 
is not, however, very great, since the period of active larval life of Cy- 
clocephala seems to terminate on an average only three or four weeks 
before that of Lachnosterna. My detailed notes on the transformation 
of white grubs belonging to this genus are but few in number, hut as 
they accord with those already given by entomologists, they serve to 
support the common statements concerning the life history of these 
beetles. 

Our only species in Illinois is C. immaculata, and its larvae occur 
in grass with the other white grubs, and have been found infesting corn 
on sod. Grubs of this species collected in grass lands at Urbana, 111., 
April, 1887, had all emerged as adults July 19. Others collected from 
corn liehls April 25, 1888, had pupated, at least in part, June 20, and 
afterwards gave the imago — at what date is not now known. In April, 
1890, -tubs were collected from the 6th to the 29th from roots of corn 
from sod plowed in fall, and from a field of young oats. All but one 
of these had pupated by June 4 (some of them quite recently), and 
this one presently died. The first beetle appeared June 16, and all 
had emerged as adults (five males and eight females) June 19. 

A dozen of the beetles bred from this collection were placed in a 
breeding cage and furnished regularly with fresh sods. By July 2 
they bad laid numerous eggs among the grass roots, and five days later 
one of these had hatched. July 26 several young larva? were living and 
doing well, but by August 10, through some misadventure or misman- 
agement, all had died. Again, twenty-one larva? of Cyclocephala turned 
out by the plow in an old corn field near Urbana May 2, 1891, were 
placed in a breeding cage. No notes were made on this collection until 
July 10, at which date imagos had emerged, and numerous eggs of this 
species were found in the earth, deposited singly like those of Lach- 
nosterna. 

In electric light collections made April 11 and 12 (thirteen days in 
May, fifteen days in June, and thirteen days in July, 1887, this species 
first appeared June 10, became abundant by the 17th and 18th. con- 
tinued so until the 1st of July, and disappeared July 14 — both begin- 
ning and continuing decidedly later than any of the six species of 
Lachnosterna collected at the same time. 

NATURAL ENEMIES. 

In the struggle for existence the white grubs and the June beetles 
enjoy many pronounced advantages, and are subject to relatively few 
and feeble checks on their multiplication. The large size and the sub- 



108 

terranean habit of the grubs protect them in great measure against two 
of the three principal classes of natural enemies of insect larva?; namely, 
birds and insect parasites. They are more liable to fungus parasitism, 
it is trite, but many kinds of much less abundant insects suffer far more 
heavily therefrom, and authentic reports of the notable destruction of. 
our American white grubs by fungus parasites are rare. The beetles are 
especially protected by their large size and heavy armor, by their noc- 
turnal habit and their skill in hiding themselves by day, by the enor- 
mous numbers in which they appeal', and by the relatively short term 
of their adult life. Cold and heat, drouth and wet weather have little 
noticeable effect upon these insects in any stage, and even starvation 
does not kill the grubs, for in the absence of other food they can live 
for months on earth alone. 

Great as the number doubtless is of individuals of the several spe- 
cies which fall victims during the year to various enemies and other 
hostile agencies, the evidence now before us does not warrant us in 
placing any considerable reliance on these natural checks to the multi- 
plication of the white grubs, but we are rather led to conclude that 
American agriculture must look to its own resources for a remedy. If, 
however, we take into account the fact that our common white grubs 
are native insects, most of them living originally in the prairie sod, 
which formed a denser, more uniform, and more continuous covering 
to the surface of the country than the crops now raised by the farmer, 
and further recall the fact that under these primitive conditions these 
insects rarely produced any conspicuous effect upon our native vegeta- 
tion, we may infer with some confidence that they are not likely to in- 
crease indefinitely and inordinately, but that the natural checks which 
held them primitively within a certain well-defined limit will reassert 
themselves under the not very different conditions of a developed agri- 
culture. Such data as we have concerning the enemies of these insects, 
animal and vegetable, are presented here more as an indication of the in- 
completeness of our knowledge, than because of their present practical 
value. 

Birds. — White grubs and June beetles are eaten to some extent by 
a considerable variety of birds, doubtless by many more than my cullings 
of the scanty literature of this subject have brought to light. 

In my own studies*, I have found June beetles eaten by the robin, 
catbird, brown thrush, wood thrush, hermit thrush, bluebird, and 
meadow lark ; Mr. E. V. Wilcoxf has found both June beetles and white 
grubs in the stomachs of robins J : and Glover long ago recorded the oc- 
currence of June beetles in the stomach of a woodpecker (Rep. U. S. 
Comm. Agr. 1865, p. 38). Dr. A. K. Fisher§ reports the occurrence of 
these beetles in the food of the red-tailed hawk, the red-shouldered hawk, 
the broad-winged hawk, the sparrow hawk, the screech owl, and the 
great horned owl ; and white grubs in that of the red-shouldered hawk, 
the sparrow hawk, and the barred owl. Dr. C. V Riley's assistants** 
recognized fragments of the beetles in the stomachs of six English 

* Bull. 111. State Lab. Nat. Hist., Vol. I, Xo. 3. pp. 93, 94, 101, 105, 109, 120: 
Trans. 111. Hort. Soc. 1880, p. 23R. 

t Bull. Ohio Agr. Exner. Station, No. 43 (1892), p. 127. 
± See also Lintner's 9th Rep. St. Ent. X. Y. (1893), p. 356. 
§ Bull. 3, Div. Economic Ornith. and Mammalogy, U. S. Dept. Agr. 
** Bull. 1, Div. Economic Ornith. and Mammalogy, U. S. Dept. Agr., p. 111. 



109 

sparrows, and four large while grubs in one of this species, out of five 
hundred and twenty-two specimens examined. 

To this list 1 can add only the crow* and the blue jay, on the au- 
thority of Dr. B. 11. Warren, author of the "Birds of Pennsylvania/' 
the chuck-will's widow ("Insert Life,'* Vol. II., p. 189), the king bird 
(Lintner) and the crow blackbird, whose habii of picking up white grubs 
after the plow is a matter of common observation. 

Of these twenty species, taking into account their numbers and 
their feeding habits, 1 judge that the robin, the catbird, the brown 
thrush, and the crow blackbird devour much the largest numbers of 
these insects, f although it is possible that if the smaller insectivorous 
hawks — the Iparrow hawk especially — were permitted to increase freely 
they would equal or surpass any of these, because of the greater number 
of insects which they take at a meal. Chickens, ducks, and turkeys are 
fond of white grubs, and may often be seen scattered over freshly plowed 
ground in search of them and other subterranean insects. 

Mammals. — The only native mammals known to feed on these in- 
sects in any considerable numbers are moles, ground squirrels, and 
skunks — none of them very likely to be tolerated by the farmer, what- 
ever may he their insectivorous habits.J 

Among the domestic animals, pigs are well known as eager hunters 
for white grubs, in search of which they diligently root up an infested 
turf ; a fact which may sometimes be advantageously applied for the 
protection of corn to follow upon grass. 

Injects. — The special insect enemies of the white grubs now on 
record belong to three or, possibly, four species, two of them hymenop- 
terous and. one dipterous, a second dipterous insect bred by us from 
dead white grubs being doubtfully parasitic. To this number I am 
able to add another hymenopterous parasite, Pelecinus polytwator, a re- 
markable insect whose larval history has heretofore been wholly un- 
known. From a collection of white grubs obtained from an orchard at 
Champaign, Illinois, May 9, 1892, and kept in a breeding cage at my 
office insectary, a specimen of Pelecinus polyturator emerged August 
26, 1892. As the parasite was seen in the act of emerging from its 
pupal envelope, there can be no doubt of either the fact or the date.§ 
An examination of the remains of the grub containing the pupa skin of 
the parasite showed that the former belonged to the species L. gibbosa. 
My office specimens of the adult of this parasite are recorded under nine 
collection numbers, all bearing dates in late summer and early fall — 
July 21, 26, August 1, 2, 11, 16, 28, and September 1 and 16. It is 
hence probably single brooded, maturing in July and August. 

Perhaps the most destructive insect enemy of the white grub is 
Tipliin inornata, Say, a hymenopterous species which we have never 
bred, but which has been reported by Dr. Eiley** to occur occasionally 

* Townend Glover also records the destruction, by crows, of great numbers 
of both grubs and beetles. 

t Nine out of forty-four robins shot by me in April, May, and June had eaten 
June beetles ; six catbirds out of forty-one ; and twelve brown thrushes out of 
forty-three. 

J Raccoons and bears, both of which are said to be fond of these insects ("In- 
sect Life." Vol. Tf., p. 3 73) are still less likely to be permitted to indulge their lik- 
ing. Radsers and weasels are said by Riley to devour the grub (Sixth Mo. Rep.). 

§ The adult Pelecinus, its pupa skin, and the remains of the parasitized grub 
are all in my laboratory collection. (Nos. 18843, 18844, and 18845.) 
** Sixth Ann. Rep. State Ent. Mo., p. 122. 



110 

in very large numbers in ground infested by Laclmosterna larvae. He 
says: "One can scarcely dig for half an hour in any soil in this part 
of the country, without meeting with a curious egg-shaped cocoon, of a 
pale golden brown or buff color, and with a soft exterior surface, in 
touch as well as in color reminding one of the punk used by dentists. 
Upon cutting this cocoon open, it will be found to consist of about a 
dozen delicate layers, the outer ones soft and loosely spun, the inner 
ones more and more compact and paler in color. Within this cocoon, 
if fresh, there will be found a whitish grub which, though lacking legs, 
has the joints of the bod}', at the sides, swollen so as to look like the fleshy 
pseudopods possessed by many larvae. * * * From having repeat- 
edly found the head parts of some Lamellicorn larva attached to these 
cocoons, I had long suspected that such larvae formed the food of this 
Tiphia, and on carefully examining these head-parts I recognized them 
as belonging to the common white grub. But all doubt as to this fly 
being parasitic on said white grub ceased when, in 1872, Mr. A. W. 
Smith, of St. Louis, brought me a number of the cocoons which he 
had taken from a low part of his farm on the Illinois bottom, where 
the white grub was very thick, and the yellow cocoons so numerous as 
to attract attention."* 

Ophion bifoveolatum is likewise reported by Eiley as a white grub 
parasite (Proc. Ent. Soc. Washington, Vol. II., p. 134), and this was 
quite probably the species of Ophion bred at my office in 1886. From 
white grubs brought to the insectary April 27 the specimen emerged 
May 11, but was lost from my collections before being determined spe- 
cifically. 

A tachinid fly has also been found parasitic oh the grubs (Proc. 
Ent. Soc. Washington, Vol. II., p. 134), and a second fly, Microphthedma 
nigra, Macq., has been repeatedly bred by us from the dead bodies 
of white grubs. The habits of the family Dexida?, to which this last- 
mentioned insect belongs, make it doubtful, however, if these flies may 
not have developed from eggs laid on the bodies of grubs already dead. 

Tiphia inornata, mentioned above, ought probably to be called a 
predaceous rather than a parasitic insect, as it attacks the grub from 
without, and devours it bodily. Ants destroy white grubs in breeding 
cages,f and very possibly attack them sometimes in the field. It is quite 
likely that various other predaceous insect species, ground beetles espe- 

* "Tiphia inornata. Larva. — Length 0.25-0.50 inch when full grown; greatest 
diameter 1/3 the length ; largest in middle ; 12 joints and a subjoint. exclusive of 
head. Head bent over on the breast. Color translucent-white, with a broad, trans- 
verse, opaque wrinkle around each joint : on all the stigmata-bearing joints except 
1, this wrinkle is constricted into two ellipsoidal pieces dorsally. strongly bulging 
laterally into semi-oval tubercles, like pseudopods. and subobsolete ventrally. La- 
bi-urn edged with brown. Stigmata small, circular, brown, and placed on posterior 
part of joint 1. and on anterior part of joints 4-11. Anal slit transverse. 

"Described from 13 specimens. The color becomes more yellowish in alcohol. 

"Imago. — This insect is very variable in size, 2 male, 7 female specimens which 
I have bred from the cocoon ranging from 0.35 inch to 0.68 inch in length of body. 
The wings are either very faintly or more deeply smoky-yellow. The color is jet 
black, but on my largest female a faint bluish or purplish hue is noticeable. In 
studying by the light of the specimens before me. Say's three descriptions which 
follow, I am forced to the conclusion that they all refer to but one species. Certain 
features common to all the specimens are curiously omitted in one or other of the 
descriptions, and inserted in one or both the others, while every feature mentioned 
belongs to the one species taken in its variations. It bcomes a question, in such a 
easp, which name to use, but I employ the first because it is appropriate, and seems 
to have been the only one used by subsequent authors." — C. V. Riley. 

t Fifth Ann. Rep. Vt. Agr. Exper. Station (1891), p. 153. 



Ill 

dally, may devour white grubs occasionally, as has indeed been sug- 
gested by Riley (Sixth Bnt. Rep. Mo.), but I have no record of precise 
observations to that effect. The fact that the beetles may sometimes 

fall a prey to carnivorous insects, is shown by two specimens brought 
to my office by a student of the University, May 21, 1891. One of these 
was an example of L. hirtidda, which he had found with the tip of its 
abdomen torn open, crawling up a stem of grass. The other was a 
C/ilain'iis tomentosus, round clinging to the Lachnosterna and feeding 
upon its viscera partly drawn out of the wound. The frequency with 
which mites are found clustered upon white grubs in their earthen 
cells,* especially upon those recently dead or in a weakened condition, 
has given rise to the supposition, hitherto not experimentally verified, 
that these mites may be parasitic on the grubs. 

On the whole, the general tenor of our own observations, as well as 
those published by other entomologists, must lead us to attach compar- 
atively little economic importance to the insect enemies of white grubs, 
whether predaceous or parasitic. 

Reptiles and Amphibians. — The fact that the toad occasionally eats 
June beetles has been reported (Proc. Ent. Soc. Washington, Vol. I., p. 
69,) and could no doubt be verified extensively by dissections of toads 
made at times when the June beetle is abroad. Frogs must likewise be 
placed on the list of the natural enemies of these beetles. f Prof. Per- 
kins, of the University of Vermont, has found as many as ten in the 
stomach of a single frog of medium size.J It is altogether likely that 
insectivorous reptiles, serpents especially, would be found to destroy a 
still greater number of these insects, but no studies have been made, to 
my knowledge, on this point. 

Fungi. — But one contagious disease of the American white grub 
occurring in nature has been positively and definitely connected with a 
fungus parasite. This parasite (Cordyceps melolontlice) has been several 
times referred to in economic literature, first in the "American Journal 
of Science and Arts" (August, 1824). It was treated at length in an 
illustrated article published by Eiley in the "American Entomologist" 
for June, 1880. According to a correspondent of Walsh's in 1869, it has 
sometimes been very common in Virginia ;§ and Mrs. Treat reported 
the occurrence of thousands of infested specimens in Benton county, 
Iowa, in 1865.** Perkins mentions it as infesting grubs of Lachno- 
sterna in Vermont. ff This species is, so far as known, incapable of arti- 
ficial cultivation, and could consequently be used for insecticide purposes 
only by distributing as carriers of infection white grubs which had been 
in contact with others infested with it. Indications have not been want- 
ing of the occurrence of a bacterial disease native to our Lachnosterna 
larvae, but no precise studies have been made sufficient to warrant the 
assertion that such bacterial diseases really occur. The common insect 
parasite, Sporotrichum glolmliferum, the so-called white fungus of the 

* Fifth Ann. Rep. Vt. Agr. Exper. Station (1891), p. 147: Rep. U. S. Dept. 
Agr. 1892. p. 165. 

t "Insect Life," Vol II., p. 195, and Trans. Wis. State Agr. Soc, Vol. XIX. 
(1881), p. 297. 

t Fifth Ann. Rep. Vt. Agr. Exper. Station (1891), p. 153. 
S Am. Ent. Vol. I., p. 91. 
** Am. Ent, Vol. II., p. 53. 
ft Fifth Ann. Rep. Vt. Agr. Station (1891), p. 148. 



112 

chinch bug, has never been found by us infesting Laclmosterna larvae in 
a state of nature, although these larvae have been proven quite suscep- 
tible to it in the course of our experimental work. June beetles have 
been frequently found, however, with this fungus growing upon their 
dead bodies, but, for all that is clearly known to the contrary, it may 
have taken its start upon them after the death of the beetles. 

In Europe, according to Giard and Krassilstschik, three diseases of 
the European white grubs have been detected : one of them due to a 
fungus infection by the species most commonly known as Isaria densa, 
Link (=Botri/tis tenella, Saccardo) ; and the other two, bacterial dis- 
eases studied by the last-named author. 

These fungous diseases will be more fully treated in the following 
section, where numerous experiments for the infection of the white 
grubs will be described in some" detail. 

PREVENTIVE AND REMEDIAL MEASURES. 

If we use the word remedy for measures intended to arrest an in- 
jury already begun, and prevention for measures applied in advance of 
such injury, we must say that efficient remedies for the injuries of white 
grubs are but little applicable to their work in corn, and that we are 
confined consequently, for the main purposes of this article, to a dis- 
cussion of preventive measures only. Such measures of prevention may 
be either local or general : applied, in the first case, to the field in which 
corn is to be planted, and intended to forestall injury in that field only; 
or, in the second case, applied elsewhere or more comprehensively, with 
a view to a more general effect in reducing the number of white grubs 
over a larger area. 

Local preventive measures can take effect only on the white grubs 
themselves, while the most valuable general measures are those directed 
to the destruction of the June beetles before their eggs are laid. 

Local Prevention. — It is now well settled, as has been shown in the 
preceding pages, that at least some species of the white grubs may be 
freely and abundantly bred in fields of corn; but it still remains true 
that by far the greater number of those in the country at any time have 
arisen from eggs laid by the beetles in ground bearing a crop of grass; 
and that corn is consequently much more likely to be damaged if planted 
on sod than if it follows clover, some small grain, or corn itself. 
The first effort of the corn farmer threatened by these insects should 
consequently be directed to clearing the grubs out of the grass land 
which he wishes to plant to corn. For this purpose it is very desirable 
that hogs should be pastured for a considerable time on meadows or 
pastures before plowing for corn, and that they should also be given the 
run of the field while it is being plowed. This measure will be practi- 
cally useless, however, under ordinary circumstances, if resorted to later 
than October or earlier than April, as in the interval between these 
months the grubs will be beyond the reach of pigs, buried in their win- 
ter quarters. 

Further, I do not, myself, in the least doubt the great profit to the 
average farmer of providing for the collection of white grubs after the 
plow, by hand, in soil where they are particularly abundant, especially 
where any kind of cheap labor may be had. In estimating the value of 



113 

tin's method, we should hoar in mind the fad that a small number of 
grubs may do a great amount of barm to young corn on comparatively 
clean ground, because of the small amount of vegetation offered to them 

as food while the corn is young. 

Next, we should take into account the relatively small damage done 
to clover by the grubs, and the further fact that we have no present evi- 
dence that the eggs of the dune beetle are eveT laid in clover laud. It 
is consequently a good practice, so far as grub injury is concerned, to 
insert clover (sown perhaps with oats) between grass and corn in the 
rotation; and this is especially to be advised on light soils not per- 
fectly adapted to corn. Here it will have the effect not only to eliminate 
tin' griibs iii part, hut also to diminish the damage to the following 
crops of corn by increasing the strength of the land, thus helping the 
corn plant to withstand such loss of roots as it may nevertheless be 
subjected to. In this connection it need hardly he said that a generous 
treatment of the soil, by heavy fertilization, thorough cultivation, and 
the like, will diminish loss to corn by enabling plants attacked to throw 
out new roots more vigorously to take the place of those eaten by the 
grubs. Indeed, by some most intelligent and successful farmers, high 
fertilizing with frequent rotation is regarded as the essential and suffi- 
cient defense against these insects. 

The management of corn on lands containing grubs should also be 
directed especially to the protection of the plant from drouth, as, in the 
presence of these insects, dry weather takes a double effect by retarding 
root growth under circumstances which require it to be vigorously stim- 
ulated instead. 

To prevent the laying of the eggs of the June beetle in the corn 
field in May or June, it is desirable that the ground should be kept 
practically free from weeds at that time, as it is well known that a sur- 
face growth of vegetation is a strong attraction to these insects search- 
ing for places suitable for the support of the young. Some of our more 
recent observations show that the beetles are likely to deposit their eggs 
in the field from which they themselves have emerged, provided that it 
offers them suitable conditions — a fact which makes it clearly inadvisa- 
ble that a field which is badly infested one year, should be planted to 
corn the next. 

General Prevention. — The principal and most effective preventive 
measures of general promise are those for the collection and destruc- 
tion of the June beetles; before they have laid their eggs. They are 
practically confined to the following four methods, mentioned in the 
order of their importance: (a) shaking and jarring down the beetles 
at night from the trees in which they feed, and their collection on sheets 
or cloth-covered frames similar to those in use for the peach and plum 
curculio; (b) exposing light traps early in the evening in places fre- 
quented by the beetles; (c) the spraying of trees to which they resort, 
with Paris green or other suitable insecticide; and (d) the turning of 

pigs into w Hands, forest plantations, and the like, where the June 

beetles conceal themselves by day. 

These are all measures calling for cooperative action by all or at 
least the greater part, of the farmers of a neighborhood, since it is use- 



114 

less to expect any pronounced effect from isolated and individual action. 
They can only be carried out by previous agreement of those interested, 
by the offer of premiums for the beetles, or by the passage and enforce- 
ment of laws bearing equally upon all. In estimating the value of these 
methods it should be remembered that each female beetle is the average 
equivalent of a large number of grubs. 

In illustration of the effectiveness of the first mentioned of these 
methods, I quote from notes of Assistants Marten and Hucke, made in 
1891. 

May 19, 2 :40 a. m. Shaking the trees in the university forest plan- 
tation made the beetles fall very easily, the second shake generally get- 
ting all, or nearly all, there were in a tree. Those shaken from the 
trees made no effort to fly up again, and only one such came to the lan- 
tern trap near by. 

3 :45 a. m. The beetles apparently as abundant as ever on butter- 
nut and hickory. The lightest shake of either of these trees brings 
down the beetles by dozens. Butternut trees six to eight inches in dia- 
meter drop them in considerable numbers when shaken by the hands — 
so easily are they detached. 

From other notes it is apparent that the June beetles cling more 
closely to the trees early in the evening, — from eight to ten o'clock, — 
a fact doubtless to be connected with the gradual stupefying effect of 
the night clews and the cooler air towards morning. 

This is the standard method in both France and Germany for the 
control of injuries by the European white grubs. The results at- 
tained in the former country are shown by an article, "La Chasse aux 
Hannetons," published in the Revue des deux Mondes for 1878. In 
consequence of an offer of premiums for beetles in the department of 
Seine-Inferieiire, 1,149,000,000 of these cockchafers were collected and 
paid for in that year, at an expenditure of $16,000. It was estimated 
that these beetles would have given origin the following year to 23,000,- 
000,000 white grubs. The proprietor of an establishment for the manu- 
facture of sugar from beets, whose crop was seriously affected by the 
ravages of the grubs, offered a' prize of $4 for each one hundred kilo- 
grammes (about two hundred and twenty pounds avoirdupois) of the 
beetles, and obtained as a consequence 28,000,000 cockchafers, — equiva- 
lent to 560,000,000 grubs the following year.* 

Details of the common procedure in France are given by A. Walles 
in "Bulletin de la Societe Centrale &' Apiculture et dTnsectologie" 
for June, 1890. "It would be a mistake," he says, "to wait until the 
cockchafers [English name for the European equivalent of our June 
beetles] have emerged, since the whole benefit of the capture of the 
beetles will be lost if the females are given time to lay their eggs. Meas- 
ures for the destruction of these insects must be taken, consequently, from 
the time that a few begin to appear. Further, if in certain parts of the 
territory involved the capture of the beetles is neglected, the good effect 
of the procedure will be considerably diminished. These two points are 
essential and imperative. 

* Similar statements concerning enormous collections and their cost in Ger- 
many are given in Taschenberg's Practical Entomology (Praktische Insektcnkunde) 
Vol. I., Pt. II., p. 37. 



115 

"The cockchafer catchers should be provided with hooked poles, 
with an awning cloth, ot the like, and with bags for their catch. It 
will be well for them to go in little groups, and to make their rounds 

from the tunc of the first appearance of the insect, This last observa- 
tion is most important. On the 12th of May, for example [in France], 
no more than twenty per cent, of the cockchafers captured in the trees 
will be females. A little later, on the contrary, the males will have dis- 
appeared, and scarcely any but females will be found. These, however, 
will have laid their eggs. 

"The beetles may be most easily shaken down from the trees in 
which they are concealed, at the dawn of day, when they are still stupid 
with the coolness of the night, and this is, consequently, the time at 
which these collections should be made. Two persons will do well to 
work together when tall trees are to he visited. One strikes the branches 
and shakes them by means of the hook fastened into the end of his 
pole, while the other picks up the beetles. They can, of course, change 
places occasionally. When there is grass under the trees a cloth must 
be spread to catch the beetles, which would otherwise often be lost. It 
will be very easy to clear the trees of smaller size by shaking them en- 
ergetically, but not violently enough to break them. 

"It is perhaps in the canton of Mayenne that the cockchafer hunt 
is pursued by the inhabitants with the greatest method, energy, and 
perseverance. There those engaged in the chase of the beetles are di- 
vided into squads of four (men, women, or children), each of which is 
furnished with the following instruments: (1) A sheet of burlap three 
yards by two, in the ends of which two flexible sticks are fastened. 
Strings intended to support the apparatus are attached to these sticks. 
(2) A long pole armed with an iron hook. (3) A sack of coarse cloth. 
The squad being thus equipped, two hold the sheet extended under the 
branches. Owing to the flexibility of the rods at the end, the surface 
of the sheet easily takes the concave form of a common hammock. The 
branches are then shaken with the hand or with the hooked stick, and 
the cockchafers fall upon the cloth and accumulate in the center.!' 

Between 2 and 5 o'clock a. m. is the best time for capturing our 
American June beetles. If they are thus collected in very great num- 
bers, they may be most conveniently killed by throwing them into tubs 
or barrels of water with kerosene on the surface. If the number is so 
great as to be likely to be offensive if left to decay, they may be scat- 
tered upon the fields as a fertilizer. 

The foregoing method is but little likely to be brought into use on 
the scale required to make it effective unless the white grubs become, 
at least locally, more destructive than they are at present in any part 
of the State of Illinois. It is quite within the bounds of possibility, 
however, that this or some similar method will he ultimately forced 
upon the American farmer. 

Our June beetles are strongly attracted by lights ; a disposition 
which may he used for their destruction in fields. An apparatus con- 
sisting of a lantern suspended over a tub of water, placed in or near- 
trees or groves resorted to by the beetles, will often collect large num- 
bers of the adult insects, which, flying against the lantern, drop into 
the water, where thev are readily killed if a little kerosene has been 



116 

poured over the surface. This method is, however, of little value as 
compared with that above described, since it attracts males in very much 
greater proportion than females — sometimes fifty of the former to one 
of the latter. It is also ineffective on moonlight nights, and when the 
weather is cool or windy; is much more expensive; and, under the 
most favorable circumstances, less thoroughgoing. Its effect is shown 
by office notes made in 1888 and 1891. June 9 of the former year one 
hundred and twenty-seven beetles were caught in a pan fifteen inches 
across partly filled with water and kerosene, above which an ordinary 
lantern was suspended, the apparatus being placed on a bench under 
trees, in Urbana, 111. A similar experiment, made May ^, 1891, with a 
tub of water and oil and a common kerosene lamp yielded 1,290 beetles, 
of which all but forty-one were males. In this case the trap was placed 
in a small forest plantation on the University farm at Urbana. These 
beetles were all taken between 7:45 and 9:15 p. m., after which only 
now; and then one would come to the light. Later in the season no 
doubt the proportion of females to males would have been greater; but 
statements made in another part of this article, under the head "Life 
History and Habits," show that the disproportion continues throughout 
the season. 

The spraying of trees most resorted to for food is a possible meas- 
ure, since the beetles are killed by arsenical poisons — a fact demon- 
strated by laboratory experiments made by us in 1888 with oak leaves 
dipped in Paris green mixture, one ounce to twenty gallons of water. 
The expense of a general application of such an insecticide will, however, 
prevent its common use. 

'When pigs can be turned, in May and June, into groves, orchards, 
or forests infested by the beetles, they cannot fail to destroy immense 
numbers of them, since they eat them eagerly, and can easily find them, 
hidden as they commonly are by day barely under the surface of the 
ground. This is a measure only occasionally applicable. 

Remedial Measures. — Direct remedies for the attacks of white 
grubs are either inapplicable to the corn field, are of doubtful economic 
value, or are too little understood, as yet, to make them worthy of recom- 
mendation. For example, kerosene emulsion may properly be ap- 
plied to infested lawns, and, if followed by a copious watering, may kill 
large numbers of the grubs, but the cost of this material and treatment 
will preclude its use against grubs in corn ; and kainit and other potash 
fertilizers (the sulphate especially) will destroy grub&in the earth, but for 
this purpose must be used at a rate inadmissible in farm practice — 
more than a ton per acre according to Prof. Perkins (Fifth Ann. Bep. 
Vt. Agr. Exper. Station, p. 152)^ 

Among remedial measures of uncertain value may be mentioned the 
cultivation and dissemination of the fungus parasites of the white grub 
— uncertain because not yet thoroughly tested, and because such tests as 
have been made do not demonstrate the practical utility of the method. 

These parasitic fungi do, however, sometimes spontaneously de- 
stroy immense numbers of white grubs in the field, and some of them 
can be easily cultivated in quantity outside the body of the insect — 
almost as easily as mushrooms may be grown for the market. The sub- 
ject of the fungous diseases of these insects is therefore a very suitable 



117 

one for investigation, and should undoubtedly be most thoroughly 
studied from every point of view. 

THE CONTAGIOUS DISEASES OF THE WHITE GEUBS. 

The native contagious diseases of'the American white grubs are 
not, so far as known, encouraging subjects for practical use in the de- 
struction of these inserts; hut certain other insect diseases, due to para- 
sitic fungi capable of artificial cultivation, offer a more promising re- 
source. Numerous experiments have been made in recenl years in 
Prance with a native fungus parasite* of the European Larva of Melo- 
lontha vulgaris (already frequently referred to as the agricultural equiv- 
alent of our species) winch have been carried so far by Prof. A. (iiard 
as to lead to the artificial cultivation of this fungus on a large scale, 
and its sale t * » farmers as a specific for that insect. 

Experiments with this fungus for the destruction of Larvae of Lach- 
nosterna and allied American genera were made in my lahoratory in 
1892, and similar and still more extensive experiments were made with 
two other species ( Isaria leprosa and Sporotrichum globuliferurti) oc- 
curring spontaneously in America. This work was done under my own 
immediate supervision by an assistant, Mr. John Marten, from wdiose 
report I take the following statement of methods and results: 

Two culture tubes of Botrytis tenella were ohtained in 1H'.>2 from 
a Parisian firm of chemists, who offered the spores of this fungus in 
glass tubes for sale; and another was received directly from Professor 
Al Giard. March 31, 1893, fifty grubs taken from a rotten oak log — 
most of them Polymoechus brevipes and the remainder Serica vesper- 
Una — were thoroughly dusted with a portion of the contents of one of 
these tubes, and were then placed in an earthen dish with a quantity of 
the rotten wood. A check lot was estahlished under similar conditions, 
hut not dusted with the spores. The first effect of this treatment- was 
observed April G, when a single larva each of Serica and Polymoechus 
was found dead, the latter with flabby thorax and the abdomen some- 
what hard. This lot of larvae was examined at intervals of two days, 
and April 8 one more was found dead, April 10 sixteen, on the 12th 
seventeen, on the 14th one, on the 16th three, on the 18th four, and, 
finally, May 2, sixteen more — making forty-nine in all. 

Infection by this fungus is unmistakably indicated by a pale pink 
tint of the dead larvae, deepening to a definite rosy color, which disap- 
pears, however, with the development of spores upon the surface of the 
grub. This characteristic color was shown by twenty of the above larva?, 
the first exhibiting it April 8. It was noticed that the Serica larvae, 
although seemingly affected like the others, did not change color in 
this way. An external mycelium was first shown April 16, on a grub 
which had died on the 8th and had then been transferred to damp sand 
and covered with a bell jar. Others showed this external growth on the 
18th and 20th, while spores first appeared April 26. From such spores 
successful cultures were made in test tubes of agar-agar, the culture 
medium assuming the deep red color to which this fungus gives rise. 
Proof was consequently complete of the destruction of at least a con- 
siderable number of these grubs by a thorough infection with spores of 

* Botrytis tenella or Isaria densa, as it is variously called by different authors. 



118 

Botrytis tenella. In the check lot, in the mean time, three larvae had 
died; one on the 14th and two on the 18th of April — all of them, how- 
ever, without any appearance of fungous affection. 

A single experiment was begun May 9, 1892, intended to test the 
possibility of the transfer of the disease characterized by the fungus 
Botrytis tenella from one white grub to another in the earth. For this 
purpose thirty Lachnosterna larva? were placed in a breeding cage and 
covered with earth, and with these were buried separately five dead 
grubs covered with a dense growth of the spore-bearing mycelium of 
Botrytis from one of the experiments just described. Wheat was sown 
in the cage to furnish natural conditions and to afford food, and a 
check lot was established, similarly provided for. Seven days there- 
after no effect was visible, and one grub was dead in the check. At the 
end of a fortnight two larva? had died in the experimental lot, but with 
no appearance of a fungus mycelium. One month later (June 23) 
sixteen living larva? were found in this cage, one had died from hy- 
menopterous parasitism, and the eleven remaining were dead, but Avith 
no appearance of a fungus growth. Matters remained in substantially 
this condition until July 5, when one additional dead larva was found, 
together with two living pupa?. August 26, when the experiment was 
abandoned, the cage contained eleven adult June beetles (Lachnosterna), 
one remaining pupa, and a second larva killed by a hymenopter- 
ous parasite (Pelecinus polyturator). The dead white grubs whose re- 
mains were detected in the earth showed no trace of fungous infection, 
and the check cage was reported, by the assistant who performed the 
experiment, in practically parallel condition. 

From the foregoing it appears that no clearly distinguishable ef- 
fect was produced by this attempt at artificial infection. 

Similar experiments with this same fungus species were made in 
1892 by Prof. Herbert Osborn, of Ames, Iowa, and by Mr. F. W. 
Mally, at Washington, both under direction of Dr. Riley, Entomologist 
to the U. S. Department of Agriculture.* 

By Prof. Osborn, forty-three Lachnosterna larva? were used in two 
experiments and a number not given in a third, with the effect to con- 
vey the fungus only to a single grub ; and here, as no culture experi- 
ments are. given, it seems possible that some other fungus may have ap- 
peared. 

In Mr. Mallv's experiment nine grubs were used in two experi- 
ments, and eighty-eight others were kept as checks. Here also the 
treatment was without result. 

The material used by Osborn and Mally was apparently derived 
from a commercial source (Fribourg & Hesse, 26 rue des ficoles, Paris), 
and may have been in a condition inferior to that from Prof. Giard, 
with which my own experiments were made. 

May 25, 1892, a third experiment was begun with this fungus. 
Fifty grubs, chiefly Cyclocephala, with a few Lachnosternas, were thor- 
oughly dusted with spores of Botrytis tenella and placed in a. cage with 
blue-grass sod, a check lot being established at the same time. June 
29, this cage was overhauled, and ten live grubs, three dead ones, two 
pupa? and eleven adult Cyclocephalas were found. One of the dead lar- 

* Rep. U. S. Dept. Agr., 1892, p. 163. 



11!) 

v;v had developed white mycelium; another was characteristically pink 
in color; while the third showed no signs of disease. The dead larvae 
were placed on damp sand, and by July 8 one had formed spores of 
Botrytis from which successful cultures of tenella were afterwards ob- 
tained. The check lot developed fewer imagos, and contained a dead 

larva and pupg on dune 29. These failed to develop parasitic' fungi 
when placed on damp sand, and this experiment was not carried farther. 

Perhaps the most successful attempt to kill our common white 
grubs with this Botrytis in our breeding cages began August 20, 1892, 
when nineteen grubs from a corn held were thoroughly covered with 
spores from a culture made in agar-agar in July. The dusted grubs 
were placed in a breeding cage, without food, and moistened from time 
to time with water. September 34 ten of them were dead, and spores 
had formed on four. Within the hodies of the others a mycelial growth 
was discernible, but none appeared on the outer surface. The cage 
was not again disturbed until March 28, 1893, when eight more dead 
grubs were found, only two of them showing fungus spores. The six 
others contained no mycelium, and probably died from other causes. 

Experiments with Isaria leprosa, Ft., were begun April 19, 1892, 
in accordance with a suggestion made by Dr. Roland Thaxter, from 
whom a culture tube of this fungus was received March 21. This cul- 
ture was repeated on agar by Professor Burrill of the University of Il- 
linois, and April 19 twenty grubs were dusted with spores from this 
second growth, and placed in an earthen vessel which was filled with 
leaf mould and sunken in the earth. Grubs died in this lot April 23, 
25, and 27, most of them becoming firm to the touch and of a dusky 
brownish hue. The record shows the death of thirteen, in all, of this 
experimental lot up to May 20, at which time ants invaded the cage, 
and the experiment was discontinued. Five dead specimens trans- 
ferred to damp sand May 30, simply decayed without visible fungus 
growth. Only two of the lot, in fact, formed a mycelium, and none 
matured spores. 

The second lot of larvae, thirty in number, Cyclocephala and Lach- 
nosterna mixed, was dusted May 2.1. 1892, with spores of Isaria le- 
prosa, from the above-mentioned culture on agar. They were placed in 
a breeding cage and left undisturbed until June 29, when five dead 
larva\ fifteen living ones, two pupa?, and one adult Cyclocephala were 
found, the remaining seven having died and disappeared. Two of those 
taken dead from the cage were placed on damp sand June 29, and grew 
the fungus rapidly in the form of stalk-like bundles which bore spores 
abundantly by July 1. Agar cultures macle from these spores on the 
8th of July were indistinguishable from the original culture or from 
the fungus growing on the grubs. There was no appearance of a fun- 
gus growth on any of the grubs in the check lot corresponding. 

The common parasitic fungus Sporotrichum globuliferum, char- 
acteristic of the so-called white muscardine of the chinch bug, was also 
used by us at this time in these white grub experiments, and seemed on 
the whole more efficient than either Botrytis tenella or Isaria leprosa. 
April 19, 1892, thirty grubs taken from an old corn field were thor- 
oughly covered with spores of Sporotrichum from a culture made on 
corn meal wet with beef broth. This culture was derived directly from 
—9 E 



120 

dead insects which had beeu collected at Urbana February 23. The 
specimens were moistened and then rolled about in the fungus spores 
until they were almost completely covered, looking as if they had been 
rolled in flour. They were buried in leaf mould in a crock, which was 
sunk in the earth in the insectary, and kept covered with a board and a 
wet cloth. The first result appeared April 25, when one grub was dead 
and two more were scarcely alive. Others were found dead the 27th 
and 30th, May 2, 7, and 15, and June 1 and 15 — twenty-nine in all. An 
external mycelium appeared first April 30, and by May 15 it was pres- 
ent on twenty-two of the grubs, and by June 15 on all but four of the 
lot. Spores were first formed (on two specimens) May 3, and by 
June 1 on several others also. 

A second lot of thirty grubs was dusted with spores of Sporo- 
trichum globuliferum May 9, 1892, from the same culture as that used 
in the above experiment. May 16 nine grubs were dead, and by June 
23 only seven remained alive. Later, three of these died and four be- 
came adults. Dead examples transferred to damp sand May 16, had 
developed spores of Sporotrichum by May 23. From two of them an 
external growth of fertile hyphse took the form of long flattened sheets, 
or bundles, of threads, which spread over the sand three fourths of an 
inch in every direction. Spores were formed in immense numbers on 
the margins and upon the surfaces of this growth. These were ripe by 
July 8, and successful cultures of Sporotrichum globidiferum in its 
usual form were made upon agar by their use. The bodies of those 
grubs that died in the earth after infection, and were left under ground, 
did not grow an external mycelium if the earth was kept wet, but rap- 
idly decayed instead, leaving only the thicker chitinous portions of their 
skeleton to indicate their fate. It would seem from this and previous 
experiments that excessive moisture in the earth may possibly prevent 
the post mortem fruiting of Sporotrichum globuliferum by causing a 
too rapid bacterial decomposition of its host. 

Three grubs had died in the check lot during the period of the 
preceding experiment, but none showed any trace of fungus parasitism. 

Two other lots of white grubs, nineteen in each, were treated with 
Sporotrichum spores obtained from cultures August 26, 1892. By Sep- 
tember 24 eleven were dead in one lot and eight in the other. In this 
experiment, as in the preceding one, the dead grabs decayed rapidly when 
left in the earth, and only those lying on the surface, or buried in 
comparatively dry earth near it, ever developed spores. 

So far as we may judge from laboratory experiments only, it would 
seem possible that artificial cultures of Sporotrichum globuliferum may 
be found useful for the destruction of white grubs in the field. Much 
practical experiment will be needed, however, to test this supposition 
thoroughly. 

The most abundant native fungus parasite of the grub, Gordyceps 
melolonthce, is not, so far as known, capable of artificial cultivation, 
and if used at all, according to our present knowledge of its life his- 
tory it can be conveyed to healthy insects in the "field only by infection 
methods in which grubs parasitized by this fungus are used as the start- 
ing point of the infection. I am not aware, however, that any success- 
ful experiments to this effect have yet been made. 



121 

DESCRIPTION OF GRUBS. 

Until the publication of the Seventeenth Report from this office no 
distinguishing larval characters had been recognized Eor the Larvae of 
Lachnosterna, and even Cyclocephala had not been separated in the 
larval state from the other genera. It has not yet proven possible to 
find strict specific characters for the Lachnosterna larvae, the distin- 
guishing features recognizable being rather those of groups than of spe- 
cies. Three such groups have thus far been recognized among larvae 
subsequently bred, first represented by hirticula and rugosa, the second 
by fusca and mversa, and the third by gibbosa. 

< 1 en us Cyclocephala. — The tip of the abdomen and the summits 
of the folds on the backs .of segments four to nine are crowned with 
short brown hairs, not thickly set. Segments one to nine are short, ten 
and eleven are equal and twice as long as nine, twelve is more than 
three times as long, and segment thirteen is very short and followed by 
a large round anal plate which attains the tip of the abdomen. The 
anal slit is transverse. The hairs on the ventral surface of the last seg- 
ment are uniform and irregularly scattered. The front and clypeus are 
a little roughened, the labrum somewhat more so; the mandibles slight- 
ly sulcate. 

G. immaculata (Plate XII., Fig. 8; and Plate XIII., Fig. 1 and 
2). — The body of this species is cream-colored, and is covered with 
scattered soft brown hairs; the spiracles are orange; the head is fer- 
ruginous, with a short longitudinal brown line behind the usual frontal 
V, and a black dot at the base of each mandible. The first joint of the 
antennae is globose, the second is cylindrical, three times as long as the 
first, swollen near the distal end, the third is longest of all, the fourth 
shorter and prolonged into a short tooth anteriorly on the under side, 
the fifth as long as the second and tapering to a point. 

Genus Lachnosterna. — Body covered with soft brown hairs, the 
tip of the abdomen and the summits of the folds on the backs of seg- 
ments four to nine covered with short stiff hairs, thickly set. The spir- 
acles are ferruginous. Segments one to nine are short, ten and eleven 
are equal in length, twelve is one half longer than eleven, thirteen still 
longer than twelve, and the anal plate is small, triangular, anterior 
margin rounded, not attaining the tip, the anal slit consequently angu- 
lar. On the ventral side of segment thirteen is a triangular patch of 
conspicuous brown hairs, the outer of which are simple and pointed, 
the inner flattened and hooked at the tip, with a median double row 
of mucronate hairs, inclined inwardly, extending lengthwise through 
the middle of the patch. The mandibles are sulcate above, the anten- 
nal joints variable. 

L. fusca and inversa (Plate XII., Fig. 5). — In these larvae the 
subanal spines or hairs are relatively short and weak, the greater part 
of the hairs being hooked, these hooked hairs forming a large triangu- 
lar patch on each side of the middle line, extending outward as far as 
the ends of the anal slit. The spinules of the double median row are 
scarcely thicker or more conspicuous than the hooked hairs adjacent. 
The two rows are parallel, extend about two thirds the length of the 
ventral surface of the segment from the anal slit forward, and are sep- 



122 

a rated from each other a distance about equal to the length of a spinule, 
ine distance between the spinules in a row being approximately half as 
great. The number of spinules is from twenty-one to twenty-five in 
each row. 

L. hirticula and rugosa (Plate XII., Fig. 2 and 3). — In this group 
the median rows of mucronate spinules are much more prominent than 
in the preceding, the bases of the spinules being decidedly thicker than 
the hairs adjacent, and the spinules placed much more closely in a row 
(almost in contact), the rows being decidedly shorter — about half the 
length of the ventral surface of the segment — and stopping short of 
the anal slit. The rows are also further apart — a distance about twice 
the length of a spinule. The hooked hairs are fewer and more sparsely 
placed. Spinules about twenty-nine in a row. 

L. gibbosa (Plate XII., Fig. 7). — A much smaller larva than the 
preceding, characterized by a still greater shortening of the median ave- 
nue through an approximation of the hairs and a lateral thickening of 
their bases, these now becoming at least twice the diameter of the hairs 
adjacent. Tips of the spinules strongly inclined, nearly meeting in the 
middle, spinules of each row contiguous. The rows approximate at the 
ends, and extend about one third the length of the ventral surface of 
the segment. Patch of hooked hairs much reduced in size, not reaching 
ends of anal slit, but extending farther forward than the ends of the 
rows of spinules. 

LIST OF ILLINOIS SPECIES OF LACHNOSTEHNA. 

There are thirty-two species of white grubs belonging to the genus 
Lachnosterna credited to Illinois by the collection of the adults, twen- 
ty-six of which (marked with a star) are in my office collections. The 
habits of the larva? of these species are so far as known practically iden- 
tical, but the greater part of them have of course never as yet been 
bred separately to the imago. 

L. lanceolata, Say.* Pare, Central and Southern Illinois. 

L. prsetermissa, Horn.* Rare, Southern Illinois. 

L. glaberrima, Blanch. Rare, Illinois. 

L. ephilida, Say.* Frequent, Southern Illinois. 

L. longitarsus, Say.* Infrequent, Illinois. 

L. gibbosa, Burm.* Abundant throughout State. 

L. hirtiventris, Horn.* Rare, Central Illinois. 

L. congrua, Lee* Infrequent, Illinois. 

L. prunina, Lee* Rare, Northern Illinois. 

L. crassissima, Blanch.* Infrequent, Central and Southern Illi- 
nois. 

L. inversa, Horn.* Abundant throughout State. 

L. bipartita, Horn.* Infrequent, Southern Illinois. 

L. micans, Knoch.* Infrequent, Central and Southern Illinois. 

L. arcuata, Smith.* Rare, Southern Illinois. 

L. dubia, Smith.* Not common, Central and Northern Illinois. 

L. insperata. Smith.* Rare, Northern Illinois. 

L. fusca, Frohl.* Abundant throughout State. 

L. grandis, Smith. Rare, Illinois. 

L. marginalia, Lee* Rare, Illinois. 



123 

L. fraterna, Harr.* Frequent, Central and Southern Illinois. 

I,, nova, Smith.* Rare, Central Illinois. 

L. corrosa, Lee. Rare, Illinois. 

L. rugosa, MEels.* Common, Central Illinois. 

L. implicita, Horn.* Frequent, Central and Northern Illinois. 

L. balia, Say.* Infrequent, Central and Northern Illinois. 

L. villifrons, Lee* [nfrequent, Central and Northern Illinois. 

L. liniula, Horn. Rare, Illinois. 

L. hirticula, Knoch.* Abundant throughout State. 

L. ilicis, Enoch.* Common throughout State. 

L. ereiiulata, Frohl.* [nfrequeni throughout State. 

L. fclepta, Horn.* Rare, Southern Illinois. 

L. tristis, Fabr.* Abundant throughout State. 

The following species will prohahly be found to occur in Illinois: 
L. gracilis, Bui in. (Can. to X. C. and Tex.) ; L. dfjvmis, Lee. (D. C, 
Kan., Col.. Ind. Ter.. and Tex.) : and /,. hnochii, Cyll. (Mass. to Ga., 
Kan., and Tex.). 

Key to the Illinois Species of Lachnostcrna* 

The classification of the June beetles presents unusual difficulty because 
of their general uniformity of appearance and the large number of species, 
and extensive use must be made of the sexual characters, external and 
internal. This difficulty reaches a climax in the group of species allied to 
fusea, which are almost absolutely indistinguishable by any other means. 
One would naturally doubt the validity of such species, but on a careful 
study of these characters, I find them easily recognizable and subject to 
but little variation, and have no doubt of the distinctness of the species 
based upon them. 

A very useful character is the sculpture of the last two ventral seg- 
ments of the male, each species presenting its own characteristic pattern. 
The internal sexual structures of both sexes seem to be a reliable means 
of identifying species. The claspers of the male rest just within the open- 
ing at the tip of the abdomen, and may be easily drawn out and examined. 
It is desirable that specimens should be mounted with the claspers pro- 
truded. In the females and some of the males the two spurs at the end of 
the hind tibia are distinctly articulated and freely movable when fresh; 
but in the majority of the species the males have one spur firmly soldered 
to the tibia, appearing like an acute prolongation of the apical margin. 
The notch or sinuation at the base of this spur is very strong and distinct 
in congrua and hirtiventris, and least developed in gibbosa, which may be 
immediately recognized, however, by its remarkable angulate spur. The 
antennal club of the male is usually much larger than that of the female. 

The antennae are usually ten-jointed, three joints in the club and seven 
in the stem, but several species have normally only six joints in the stem, 
making the antenna? 9-jointed. Besides this, there is a tendency to lose 
one joint of the stem in one or even both antenna? of individuals of 
either group, so that we may find 9-jointed antenna? in species normally 
10-jointed, and 8-jointed antenna? in those normally 9-jointed. 

Other distinguishing characters are found in the vestiture, color, and 
punctuation; the clypeus; the outline, margin, and basal channel of the 
thorax; the distinctness of the elytra! costse; the length of the antennal 
club; the teeth of the tarsal claws, etc. 

The following key makes extensive use of the characters of the male, 
without which the species could scarcely be identified with any certainty. 
The females may be determined by comparison with the males. The classi- 
fication is based on the excellent monograph of Dr. Horn, "Review of the 
Species of Lachnosterna of America North of Mexico," in Trans. Am. Ent. 



Prepared by Mr. C. A. Hart. 



124 

Soc, v. 14, p. 209; and free use is made of Mr. J. B. Smith's studies of the 
sexual structures, "Notes on the Species of Lachnosterna of temperate North 
America, with Descriptions of New Species," in Proc. U. S. Nat. Mus., v. 11, 
p. 481. 

1 Surface clothed with scales, subopaque; male with ventral segments 

carinate at middle, hind tibiae with both spurs free, and hind tarsi 

long and slender; female apterous; antennae 10-jointed. 13-17 mm 

lanceolata, Say 

Surface above glabrous 2 

Surface above pubescent or hairy 30 

2 Antennae 10-jointed 3 

Antennae 9-jointed 4 

3 Fixed spur of hind tibia short; metasternum hairy, penultimate seg- 

ment with an elevated slightly roughened transverse ridge, narrowly 
separated from the posterior margin. 15-16 mm. . .ynetermissa, Horn. 

Fixed spur of male wanting; metasternum nearly naked; slender, rufo- 
testaceous, shining; penultimate ventral segment of male rugulose, 
last ventral concave with two feeble cusps in the concavity. 13-15 
mm glaberrima, Blanch. 

Fixed spur short; similar to preceding, clypeus less distinctly emargi- 
nate; abdomen of male channeled, penultimate ventral with a de- 
pressed roughened space at middle, near hind margin, depression open 
behind, its floor with sharp blackish posterior edge, occupying a deep 
emargination of edge of segment, and separated by a small notch at 
each end from the sides of the impression, which terminate posteriorly 
in thick projecting angles. 14-19 mm ephilida, Say. 

Fixed spur long or moderately long 6 

4 Inner spur of hind tibia of male anchylosed 5 

Inner spur of male free 33 

5 Fixed spur of male short; clypeus deeply emarginate; elongate cylin- 

drical, pale yellowish testaceous, head darker; abdomen of male flat- 
tened at middle, last ventral irregularly concave. 10.5-13 mm. 

longitarsus, Say. 
Fixed spur at least moderately long 25 

6 A marked sinuation at end of male hind tibiae, at base of fixed spur, 

in line with under surface of tibia 7 

No distinct sinuation at apex of hind tibiae as described 11 

7 Subcylindrical, slender, yellowish testaceous, thorax and head darker; 

claw tooth small; penultimate ventral of male abruptly declivous at 

middle. 10.5-13 mm gracilis, Burm. 

Oblong oval, darker; claw teeth strong 8 

8 Fixed spur boot-shaped; clypeus feebly emarginate; thorax rather 

coarsely and sparsely punctate; penultimate ventral of male obliquely 
plicate each side of the middle, last segment with a deep concavity 
limited behind by a sharp elevated margin overhanging posteriorly. 

12-17 mm gibbosa, Burm. 

Fixed spur of usual form 9 

9 Abdomen of male at middle hairy and rather deeply channeled, last 

ventral with a rather smooth triangular impression, hind margin 
with a broad emargination, prolonged at middle in an acuminate 
point up the middle of the triangle, and closed by paler membrane; 
thoracic punctures coarse and close, denser anteriorly, a smoother 

median space. 17-18 mm hirtiventris, Horn. 

Abdomen glabrous at middle 10 

10 Abdomen of male deeply and sharply impressed along middle, penulti- 
mate ventral strongly and acutely emarginate, slightly transversely 
plicate each side of median channel, last ventral with broader deep 
longitudinal impression, widening posteriorly and ending behind in 
two black projecting lobes separated by an acute notch; thorax 
evenly, moderately punctate; color rufocastaneous to piceous. 15-19 1 
mm congrua, Lee. 



125 

Abdomen of male flattened at middle, penultimate ventral with a 
straight transverse carina, last ventral irregularly concave, anterior 
margin elevated; last ventral of female deeply and broadly emargi- 
nate, impressed or eroded at middle; thorax coarsely, deeply, and 
irregularly punctate; elytral punctures distinct, costa? feeble; color 
brownish to castaneous. 16.5-20 mm affinis, Lee. 

Sexual characters as in preceding; thorax very coarsely and closely 
punctate; elytral punctures feeble, costae usually well marked; color 
castaneous to piceous, pruinose. 17-18.5 mm prunina, Lee. 

11 Clypeus concave, moderately reflexed, feebly emarginate 12 

Clypeus flat, narrowly reflexed, deeply emarginate 21 

12 Penultimate ventral of male without distinct elevated transverse 

ridge 13 

Penultimate ventral with distinct elevated transverse ridge, straight 
or curved 14 

13 Penultimate ventral of male with curved rugose impressed channel along 

posterior margin at middle, in front of which is a broadly triangular, 
not elevated, rugose space, last ventral with smooth cupuliform depres- 
sion; body large and broadly ovate, subpruinose; thorax closely, 

rather coarsely, punctate. 15-21 mm crassissima, Blanch. 

Penultimate ventral with subcircular rugose impression, border widely 
interrupted behind by hind margin of segment, sometimes slightly 
elevated, last ventral with broad smooth impression; fixed spur rather 
short and broad; clypeus more distinctly emarginate; thoracic punc- 
tures rather coarse and sparse. 15-18 mm inversa, Horn. 

14 Transverse ridge deeply divided by the longitudinal median impres- 

sion; thorax coarsely and rather closely punctate, with smoother 

median line. 15-19 mm Upartita, Horn. 

Transverse ridge entire 15 

15 Surface opaque, conspicuously pruinose; thoracic punctures distinct, 

sparse, and irregularly placed, median line smoother; penultimate 
ventral of male with short arcuate ridge; fixed spur not long. 

15-17 mm micans, Knoch 

Surface shining, not pruinose; thorax not very coarsely or closely 
punctured 16 

16 Transverse ridge short, strongly arcuate; female with last segment 

emarginate 17 

Transverse ridge longer, straight or but slightly curved 20 

17 Ridge overhanging throughout 18 

Ridge not overhanging 19 

18 Ends of ridge at extreme hind margin of segment and overhanging 

the next; clypeus feebly emarginate; oblong-oval, rufocastaneous to 

piceous. 19 mm arcuata, Smith. 

Ends of ridge distant from hind margin of segment; otherwise not super- 
ficially distinguishable from the preceding. 18-20 mm. . . .duMa, Smith. 

19 Ridge small, distinct, the ends as well as the rest of the ridge near 

the middle of the segment; claspers of male symmetrical; not no- 
ticeably different from the preceding species insperata, Smith. 

20 Ridge slightly curved, ends overhanging, declivous at middle; female 

with last ventral not emarginate; closely resembling the preceding. 

18-22 mm fusca, Frohl. 

Ridge nearly straight, not overhanging posteriorly, last ventral gran- 
ulate-punctate; female with last ventral emarginate; larger and more 
robust; thorax subangulate before the middle grandis, Smith. 

21 Thoracic punctuation moderate; club of male antenna much shorter 

than stem 22 

Thoracic punctuation very coarse; club of male antenna about as long 
as stem 23 

22 Penultimate ventral of male granulate and feebly impressed posteriorly, 

feebly elevated in front, elevation continued by plications extending 
obliquely backward on each side; claspers large, expanded, with 



126 

rounded posterior outline; thoracic punctures more or less sparse. 

15-18 mm fraterna, Harr. 

Penultimate ventral of male similarly sculptured, but the elevation 
stronger and shorter, forming with the lateral oblique extensions an 
approach to an acute ridge; claspers small, deeply emarginate behind; 
thoracic punctures sparse, leaving irregular smooth spaces on the 
disk. 15-17 mm nova, Smith. 

23 Penultimate ventral of male with a semicircular elevation in front of 

a deep smooth fovea; thorax broadest at base with a smooth space 
each side of middle. 16.5-21.5 mm marginalis, Lee. 

Penultimate ventral of male with the posterior border vertical at 
middle, horizontal portion obliquely plicate each side; thorax widest 
at middle, obtusely angulate, punctures moderately close, sparser at 
sides of middle. 17-20 mm corrosa, Lee. 

Penultimate ventral broadly impressed and granulate at middle, form- 
ing an oblique declivity, at each end of which is an obtuse elevation; 
thorax widest at middle, subangulate 24 

24 Thorax with punctures irregularly confluent, a distinctly elevated smooth 

median line; last ventral of male with apex acutely emarginate. 

21.5-23.5 mm knochii, Gyll. 

Thorax with punctures dense, but not confluent, median line some- 
times smoother; last ventral of male with a broad triangular emar- 
gination, closed by membrane, at apex. 18-23 mm rtigosa, Mels. 

25 Sutural stria deeply impressed, sutural costa normal 26 

Sutural stria feeble or wanting, sutural costa scarcely elevated 29 

26 Form more or less ovate, head and thorax darker than elytra 27 

Form elongate, parallel, color uniform 28 

27 Last ventral of male convex, penultimate with a subcircular rugose 

depression, limited in front by a small narrow arcuate elevation, 
feeble at middle, on each side more distinctly and sharply elevated, 
extending obliquely outwards; clypeus deeply and acutely emarginate, 
front glabrous; thoracic punctures moderately coarse, rather sparse. 

14-17.5 mm implicita, Horn. 

Last ventral of male with smooth cupuliform depression, penultimate 
with elongate concavity at middle along hind margin, in front of 
which is a short obtuse punctate arcuate elevation; front with erect 
hairs, clypeus broadly not deeply emarginate; thoracic punctures 
rather coarse and sparse, irregularly placed. 15-16 mm. .. .balia. Say. 

28 Last ventral of male broadly concave, penultimate with a feeble arcu- 

ate elevation; front with short erect hairs, clypeus deeply emargi- 
nate; thoracic punctures coarse and deep, sparsely and irregularly 
placed, often leaving large smooth spaces. 14.5-16 mm. .villifrons, Lee. 

29 Last ventral of male concave, penultimate with an obtuse transverse 

ridge divided by a depression at middle; rufotestaceous; clypeus 
emarginate; thorax moderately coarsely punctate, not closely, but 
somewhat irregularly. 14-18 mm limula, Horn. 

30 Hind tibia of male with one spur fixed 31 

Hind tibia with both spurs free 'il 

31 Surface with erect hairs, those of elytra in rows (sometimes indistinct 

from rubbing); base of thorax channeled each side; penultimate ven- 
tral of male with a broad and long transverse impression, limited at 
each end by a smooth oblique plica, space in front slightly elevated, 
last ventral broadly concave; clypeus emarginate; thorax variolately 

and irregularly punctate. 16.5-19 mm hirticula, Knoch. 

Surface covered with short grayish pubescence; base of thorax not 
channeled; penultimate ventral of male with a broad transverse im- 
pression, a slightly oblique tuberosity at each end in front, last ven- 
tral feebly concave, broadly emarginate at apex; clypeus deeply 
emarginate; thorax very densely granulate-punctate, median line 
smoother, slightly elevated. 19-23.5 mm. (ciliata, Lee.) . .ilieis, Knoch. 



127 

32 Clypeus emarginate; surface with short yellowish recumbent hair; 

penultimate ventral of male vaguely concave at middle; thorax with 
margin coarsely serrate, coarsely and densely punctate. 17-20 mm. 

crenulata, Frohl. 
Clypeus entire 34 

33 Subcylindrical, rufotestaceous; clypeus emarginate; thorax moderately 

punctate, with smooth median line; last ventral of male longitudinally 
subcarinate at middle, anterior margin elevated each side, penulti- 
mate with sharply limited cupuliform concavity, its margin rising 
into an acute rugose tuberosity on each side, hind tibial spurs slen- 
der. 15-1G mm inepta, Fabr. 

34 Surface with yellowish hair long on head, thorax, and about scutellum, 

short on remainder of elytra; thorax coarsely, closely punctured, last 
two ventrals of male broadly transversely impressed, anterior margin 
of last ventral elevated, penultimate with a short acute transverse 
carina near the front margin. 11.5-15 mm tristis, Fabr. 

THE GEEEN JUNE BEETLE. 

(Allorhina nitida, L.) 

(Plate XIII., Fig. 7.) 

The larva of the green June beetle, Allorhina nitida, commonly 
known as a white grub where it occurs, is distinguishable from the spe- 
cies of Lachnosterna and Cyclocephala by its somewhat larger size when 
full grown; by the thick covering of short stiff hairs easily visible to 
the naked eye ; but especially by the difference in its method of locomo- 
tion upon a hard surface. The common white grubs (Lachnosterna) 
creep only by means of their legs, dragging the heavy abdomen clumsily 
along ; but the larva of the green June beetle, when thrown upon a hard 
surface, turns immediately upon its back, and moves somewhat easily 
in this position by alternate contraction and expansion of the segments 
of the bod} 7 , using the stiff hairs upon the back as an aid. 

This is a southern species, and in the Southern States largely re- 
places Lachnosterna, its larva being there known as the white grub. In 
Central Illinois it occurs but rarely, but becomes noticeably abundant 
in the southern part of the State, where it has been occasionally re- 
ported as injurious in a small way. Although it has not been found in 
corn fields, its food and habits are such as to make it altogether likely 
that under favoring circumstances it might injure corn in the same 
manner as the Lachnosterna larva — or rather as the larva of the Cyclo- 
cephala, which it more closely resembles in its life history. The grub is 
normally a grass insect, but infests likewise strawberry fields, and has 
been found by Dr. Riley to feed in confinement upon the roots of wheat. 
It seems to be less dependent upon living vegetation than even the white 
grubs, apparently living much more generally upon a rich soil. Indeed, 
the beetles seem to be attracted to manured land when about to lay 
their eggs, or to that which has been heavily mulched or contains an 
unusual amount of decomposing vegetation.* Townsend has found them 
living in clean earth under circumstances to indicate a carnivorous 
habit f 

The life history of this insect is. as already intimated, different 
from that of Lachnosterna, especially in the fact that pupation of the 

* Bull. 23 Md. Agr. Exper. Station, 1893, p. 79. 
t "Insect Life," Vol. IV., p. 25. 



128 

larva takes place in May, the beetles issuing in June. Its length of 
larval life is not known, nor the precise time or place of oviposition. 
The following description of the larva is taken from Dr. Riley.* 
"Full grown larva. — Length 40 millimetres, somewhat largest pos- 
teriori}^, subcylindrical, broader at thorax and eighth and ninth abdomi- 
nal segments, which are materially swollen. More flattened ventrally, 
with a distinct swollen lateral ridge just below the stigmata, which 
rather increases the flattened aspect of the venter. General color, 
glassy yellowish white, inclining to green or blue towards the extremity. 
Head, rather small, flattened, well inserted into the prothoracic seg- 
ment, chestnut-brown in color. Dorsal surface of the body strongly 
transversely corrugate or wrinkled, each of the chief segments having 
three distinct ridges, the whole body studded with short, thick, yellow- 
ish bristles, which are most dense on the dorsal ridges and more sparse, 
but longer, on the ventral and anal segments. Dorsally these stiff hairs 
are directed posteriorly and materially assist in the dorsal locomotion. 
The legs are honey-yellow, covered with similar stiff bristles, without 
definite tarsal claw. They are short, compared with the larvae of Lach- 
nosterna generally. Prothoracic segment with a honey-yellow horny 
plate in front of the spiracle, which, as usual, is rather larger than the 
abdominal spiracles. Mandibles short, stout, dark brown, with the 
left (looking from the dorsum) 4-dentate, and the right 3-dentate. An- 
tenna? short, 4-jointed, joints subequal in length, diminishing in width 
from 1 to 4, maxillary palpi 3- jointed, joints subequal in length, ter- 
minal narrowest at tip. Labial palpi 2-jointed, joint 1 longest, some- 
what swollen at tip, and bearing a short pointed joint 2 on the inner 
side of its tip. Labium covered with short stout bristles. Maxillae with 
long, stiff bristles on the inner surface, and with two long, sharp, black 
teeth near the tip. 

"The half-grown larva does not differ in structure or coloration." 



(Plate XIII., Fig". 3-6.) 

The occasional occurrence in corn of large thick-bodied grubs be- 
longing to a different family from the common white grubs of this ar- 
ticle, calls merely for general mention. The larva? in question are those 
of two species of large brown, flatfish, long-horned beetles (Ceramby- 
cidcc), and belong to the genus Prionus (P. imbricoi-nis and P. laticol- 
lis). They are sometimes common in prairie or pasture sod, where they 
feed upon the roots of grass, and have also been a few times reported 
in corn fields in Illinois and Missouri, doing an injury apparently iden- 
tical with that of the white grubs. These larva? are at once distinguish- 
able from the latter insects by their greater size (3 mm. in length and 
nearly half as thick when full grown), by the form of the body (taper- 
ing from the head backwards), and by the fact that it is little, if at 
all, curved. They are, further, at once distinguishable by the rudimen- 
tary and inconspicuous character of their legs. They are much more 
generally known to economic entomology for their injuries to the roots 
of the vine and apple and some forest trees than for their agricultural 
relations. 

* Bull. 23 Md. Ag-r. Exper. Station. 1893, p. SO. 



129 

b. Boots penetrated, perforated, irregularly burrowed, and more or less 

eaten off and eaten up. Underground parts of stalk usually also 

simUm-l;/ injured. 
Wireworms in soil among the roots. 
(For a discussion of the wireworm injury to corn, see this report, 

p. 24.) 
Small, slender, soft-bodied, white or yellowish-white grubs in the 

roots and ear Hi. 

THE SOUTHERN CORN HOOT WORM. 

(Diabrotica 12-punctata, Oliv.) 

(Plate XIV., Fig. 1-5.) 

Injuries to corn by the southern corn root worm have not been 
seen by us in Northern Illinois and but rarely in the central part of 
the State, but they are more likely to occur southward. Outside this 
State they have been recognized by entomologists in Ohio, Indiana, Ken- 
tucky, Arkansas, Mississippi, Louisiana, Alabama, South Carolina, Vir- 
ginia, and .Maryland. As the beetle occurs from Canada southward 
through the Atlantic region, and thence to Minnesota, Kansas, Louisi- 
ana, and Mexico, it will probably be found much more generally pres- 
ent iti com fields than the above report would indicate. 

Its injuries are very similar in general character and effect to those 
of the much more abundant and better known northern corn root worm 
(Diabrotica longieornis), with which they have doubtless frequently 
been con rounded. They are distinguishable with some difficulty from 
those due to the various species of wireworms, and it will often require 
the recognition of the larva itself to determine positively to which of 
these two classes of insects a given root injury is due. The presence of 
this root worm in the field gives origin to the usual general effects of 
the loss of roots by the plant, varying according to the age of the corn, 
the gravity of the injury, and the kind of soil and weather. A conspic- 
uous damage, noticeable on a casual inspection, may vary from the death 
of the plant to a slight retardation of its growth or to a general spin- 
dling, yellowish, and unhealthy look. 

In the young plant, about six inches high, the characteristic per- 
forations of the stalk under ground may result in the sudden withering 
of the whole plant, or, more commonly, in the killing of the central 
leaf or tuft of growing leaves — an appearance which has given to this 
insect the common name of the "bud worm" in some of the Southern 
States. In certain instances the plant has been killed, as in Mary- 
land, almost as soon as it has sprouted. 

As the season advances, the corn in affected fields is likely to be 
uneven in size, and later, as the plant becomes top-heavy with growth, 
it may fall to the earth when the soil is softened by rains, and espe- 
cially during windy storms. Having once so fallen, it will, if badly in- 
jured, fail to rise again; and it may further be seen that the plant 
has but little hold upon the ground, a whole hill, perhaps, being readily 
pulled up with one hand. As a consequence of the loss of roots and the 
general weakening of the plant, many stalks fail to set the ear, or 



130 

form only a nubbin. The injured plant also matures slowly, remain- 
ing green longer than the average, and being thus especially subject to 
injury by frost. 

A closer examination of the young plant will commonly show a 
perforation of the underground part of the stem either at or near the 
upper circle of roots. Later, as the corn plant increases in size, the 
roots themselves are seen to be gnawed irregularly, great holes or 
notches being eaten out, first in one direction and then in another, until 
the roots are severed or consumed. In the larger roots the larva may 
perhaps completely bury itself, but it is much more likely to eat in and 
out irregularly than is the smaller northern corn root worm presently 
to be described. It differs from this last species likewise in the fact that 
it commonly devours everything as it goes, leaving little or no refuse 
in its burrows; and in the further fact that it works all along to some 
extent in the base of the stalk, which it penetrates, but not deeply, 
finally causing the stalk to blacken and rot where water gets admis- 
sion to its injuries. Its attack on corn is also earlier, briefer, and much 
more vigorous and destructive, owing to the larger size of the larva and 
its more rapid growth and earlier maturity. Even in well-grown corn 
it very commonly bores into the stalk beneath the upper circle of 
brace roots, or behind the sheath of the lower leaf — habits in which 
it differs from the northern corn root worm. 

Search for this root worm should be made in or about the injured 
parts — from the middle of May to the middle of August in the lati- 
tude of the southern half of Illinois. It is a soft, slender-bodied, worm- 
like insect, a little over half an inch in length when full grown, and 
nearly ten times as long as thick. The surface is slightly wrinkled or 
warty; white when young, and yellowish when old. The head is dark 
brown, sometimes nearly black, and there is a pale brown leathery patch 
on the top of the segment next behind the head, and a nearly circular 
similar patch on the top of the last segment of the body. The legs are 
very short and small, and the skin bears only a few long scattered hairs. 

It seems most likely to attack early planted corn, and hence in the 
Northern States has been found most frequently in sweet corn. An in- 
jury of fifty per cent, is a not unusual effect of its presence in South- 
ern Illinois, and elsewhere it has been reported as sometimes destroy- 
ing almost every hill when the corn was young. 

This corn root worm has not been taken in the act of injury to the 
roots of any other plant than corn, but has once been seen eating off 
a stem of young -wheat in fall.* Lugger found the pupa? among the 
roots of a common prairie plant, the cone flower (Rudbeckia), but says 
nothing of injury to that plant ; and my assistant, Mr. Marten, re- 
ports the occurrence of young larva? among the roots of Cyperm strigo- 
sus and Scirpus furintilis — two sedges common in moist low lands, the 
roots of which presented the same appearance of injury as those of in- 
fested corn. 

The food of the adult Diabrotica 13-punctata is widely varied, ap- 
parently much more so than that of the northern Diabrotica. It has 
been for a long time commonly known as a squash beetle, eating both 

* Webster, in Bull. 45 (1892), Ohio Agr. Exper. Station, p. 203. 



131 

leaves and green fruit of squashes, melons, and cucumbers. We have 
seen it eating into pumpkins, sometimes to the depth of half an inch, 
and feeding upon clover blossoms and upon the leaves of tame and 
wild sunflowers (Helianthus). We have found it in May eating away 
the v<\<j;r* of the Leaves of young corn in the field, and in duly and Au- 
gust making small round holes in coru leaves in our breeding cages. 
In September and October it lias occasionally been taken from the tip 
of the ear of corn, feeding on the silk, and once in August we saw it 
gathering up fallen corn pollen. It has also fed upon ragweed leaves 
in our breeding cages in August. By other observers it has been re- 
ported to I'i'vd on the petals of various flowers, including roses, dahlias, 
Cosmos, and the cotton plant; upon young volunteer oats (December), 
on certain moulds, on the horse nettle (Solatium canadense), on cab- 
bage, cauliflower, and beans ; and on the leaves of plums, cherries, apri- 
cots, and raspberries. Webster has also seen it eating unripe kernels of 
wheat and corn. 

LIFE HISTORY. 

As is very commonly the case with American injurious insects, 
the life history of this beetle is incomplete. Our studies of it are defi- 
cient not only in continuity of experimental work, but even in a num- 
ber and distribution of observations and collections sufficient to give us 
a fair ground of probable inference. We are especially uncertain as to 
the number of broods and the stage or stages of hibernation. In the 
latitudes of Central and Southern Illinois it seems most likely that this 
is a two-brooded insect, but if so, data published from Alabama and 
Mississippi would make it extremely probable that it is three-brooded 
there. Webster's observations in Indiana' would lead us to suppose 
that it hibernates as an adult, he having found it feeding upon volun- 
teer oats as late as December 14, and abroad in spring as early as April 
17, at which time the sexes appeared in copula. 

Our own voluminous collection records of the adult do not clearly 
bear out the suppositions made above concerning the hibernation and 
the number of annual generations of this species. Without ever having 
made any special search for it, I find that we have actually obtained it 
in eighty-two collections, — mostly of a miscellaneous character, — rang- 
ing from April 20 to November 15. We have thus taken the imago 
once in April, six times in May, eight times in June, sixteen times in 
July, twenty-eight in August, eighteen in September, four in October, 
and once in November — a gradual rise in frequency from April to 
August, and a similar gradual decline thence to the end of the sea- 
son. In our special collections of hibernating insects this species has 
not appeared ; and in our large electric-light collections, made from 
May to September in 1886 and 1887, it occurred infrequently, and in 
no case until July. 

As we now understand the subject we may say that in the latitude 
of the southern half of the State the eggs are laid in May and June, 
that the root worms do the greater part of their mischief also in these 
months, pupating from the middle of June to the last of July, and 
yielding the beetle in July and August. The new generation commence 
to pair by the beginning of the month last mentioned, and young larvae 
of the generation following may be found early in September. 



132 

The larva has first been observed in spring in the latitude of Illi- 
nois (namely in Maryland) on May 31, and in Virginia June 18. By 
the 19th of July this brood of larvae was largely full grown in 1889, 
larvae, pupae, and freshly emerged imagos occurring at that time at 
Jacksonville, in Morgan county, in this State. We have in fact once 
seen a freshly developed beetle of this species July 5, and Webster re- 
ports it as pairing in Central Indiana in July. Dr. Eiley seems to have 
found eggs of beetles in his breeding cages July 7, from individuals 
which emerged the day preceding, the larvae having originally come 
from Virginia June 18. Garman finds the ovarian eggs of this (?) 
generation mature in Kentucky July 29, these two being as yet the only 
observations on record concerning the egg. 

The pupation of this brood of larvae is not, however, altogether 
completed in Illinois before the end of July. Indeed, larvae taken the 
20th of August at Champaign, Illinois, in 1889, were possibly of this 
same brood. The beetles have begun to pair again, however, as early as 
August 8 with us, and young root worms, doubtless of a second genera- 
tion, have been collected at Champaign September 6. Garman's obser- 
vations in Kentucky are not especially different from these, but the 
dates given for Alabama ("Insect Life," Vol. IV., p. 101) show a much 
earlier start of the species. The active larva is reported as occurring 
there from March to the middle of May, these earlier larvae beginning 
to pupate certainly by April 30, and to yield the imago May 21. The 
occurrence in Minnesota of pupae September 3, which gave the imago 
three days afterwards, is a fact which has no special bearing upon this 
life history. 

I need only add that the eggs are placed, either singly or in groups 
of two to twelve or more, according to Eiley's observations, below the 
surface of the soil near the plants, in cracks or immediately about the 
base of the plants. 

NATURAL ENEMIES. 

So far as now known, the most effective natural check on the mul- 
tiplication of this insect is a bacterial parasite (Bacillus rufans) observed 
by me to infest the larva, killing about three fourths of a considera- 
ble collection of these corn root worms brought from Jacksonville July 
19, 1889. We do not yet know what part of the larva is first attacked 
by this Bacillus, but by the time the resulting disease has reached a fa- 
tal stage, it swarms in all the fluids of the root worm, which have be- 
come practically a pure culture of this bacterial species. Infested lar- 
vae lose their characteristic yellowish tinge, becoming gray and some- 
what swollen, and after death they change color through pinkish to dull 
dark red, the internal organs breaking up to a fluid pulp, held for a con- 
siderable time in the tough cuticle of the dead larva. The fluids of 
such specimens have a milky appearance in the pale worms and a red- 
dish tint in the others. This last color is due, not to the color of the 
bacilli themselves but to an excreted coloring matter diffused through 
the fluids in which they grow. In artificial cultures, consequently, — a 
numher of which I made in 1889, — a similar color is imparted to the 
culture medium, whether this be solid or fluid. 



133 

The readiness with which this Bacillus is cultivated artificially and 
the apparent deadliness of its attack make it a very promising subject 
for experimental investigation, and it is consequently much to be de- 
sired that it it he again encountered in this or any other insect species, 
it may he thoroughly investigated from the practical point of view. 

The following description of Hie Bacillus itself and of its mode of 
growth on agar and in culture fluids will serve for its identification 
wherever found. 

Bacillus rufans, n. sp.* 

Oval or short-cylindrical to rod-like, very variable in shape and 
size, often 1 to 5 microns long and .5 to 1.5 microns wide, free ends 
rounded; occurring singly, in pairs or in rods of three or lour segments; 
Sometimes slowly motile, usually not flagellate; aerobic; non-liquefy- 
ing, chromogenic; pathogenic in insects. 

The various liquid and solid media, as well as the tissues of af- 
fected insects, are diffusely tinged with red. The color spreads uni- 
formly throughout the substances, which at first become yellowish, then, 
during two or three days, gradually deepen to orange and finally to dark 
blood-red. The growth on agar and on gelatine is smooth, shining, 
slightly elevated, more abundant upon the moister portions near the 
bottom of the tube, brownish white with scattered specks or dots of deep 
orange, usually aggregated in small blotches, the whole growth finally 
becoming a dirty cream color. Bouillon becomes tinged first near the 
surface, and the color gradually extends to the bottom, with a rather 
distinct line of separation from the still unColored deeper material. A 
fragile white or slightly stained pellicle forms, but this readily breaks 
up and settles to the bottom as a loose precipitate. The organisms 
themselves are white. They readily stain with ordinary aniline dyes. 
The staining is sometimes solid throughout, but often, especially in the 
insect fluids, there is a broad central band of white. In a slide from 
an old fluid culture many spore-like forms occur. These appear like 
the ones with only the ends of the cells stained, except that the differ- 
entiation is more marked, and they are somewhat swollen in the cen- 
tral portions, becoming broadly, instead of rather narrowly, oval, as in 
other cases. Sometimes the rod-like forms have irregular dots of white 
(vacuoles). 

Growth takes place at the ordinary temperature of the room, but 
not rapidly. Other temperatures were not tried. 

I have discovered no insect enemy of this species, but Dr. Eiley 
reports the rearing of two dipterous parasites of it; one from the larva 
and pupa, and one (a tachinid) from the beetle. Professor H. Garmanf 
notes the occurrence of small numbers of predaceous beetles and larva? 
in summer and fall with young root worms in the earth. He also men- 
tions some internal parasites of the imago — Gregarinse and nematode 
worms. 

Notwithstanding the abundance of the adult Diabrotica and its 
general distribution upon a great variety of plants, it seems but little 
noticed bv birds. It has occurred but once in my own studies of the 



* Prepared bv Prof. T. J. Burrill. from my office notes and slide 
t "Psyche," Vol. VI. (1891), p. 47. 



134 

food of birds (in July, eaten by a catbird), and was not once recognized 
by Dr. Biley's assistants in their studies of the contents of the stom- 
achs of one hundred and two English sparrows which had eaten insects. 

REMEDIAL MEASURES. 

Until the life history of this species is better known, measures of 
prevention or of remedy can scarcely be intelligently discussed. The 
fact that its injuries to corn occur without apparent reference to the 
crop of the previous year makes it unlikely that the favorite method of 
rotation will serve for the protection of corn against this species. Ac- 
cording to the scattered observations hitherto reported sweet corn seems 
to be much more liable to injury than the field varieties, from which 
fact we may surmise that the time of planting has something to do 
with the intensity of the attack. The vicinity of cucumbers, squashes, 
and other of the commoner food plants of the beetle may, however, ac- 
count for this seeming preference. 

DESCRIPTION. 

The following description of the stages of this insect is copied 
from Professor H. Garman's article in "Psyche" (Vol. VI. pp. 48, 49). 

Egg. — "Matured ova from ovaries of females are much like those 
of D. longicornis. They are white, oval, with the surface reticulated 
and sculptured so as to produce numerous hexagonal, pitted areas. Prof. 
Forbes gives the dimensions of the egg of D. longicornis as .025 inch by 
.015 inch. Ova of the spotted species measures a trifle larger, being 
.027 inch in length by .016 inch in diameter." 

Larva (Plate XIV., Fig. 4 and 5). — "Body cylindrical, tapering a 
trifle towards the extremities, composed of twelve segments behind the 
head. Skin wrinkled, papillose along the sides, white, sometimes be- 
coming yellowish just before pupation. Head dark brown, nearly black 
in some examples, with a few rather strong hairs arising from the sur- 
face; a narrow median longitudinal line of black above, and two pale 
lines which converge from the bases of the antenna?, following sutures, 
to meet at the middle line on the posterior part of the head ; ventral 
side of head pale medially. No eyes. Antenna? of three segments, 
white. Labrum dark brown. Mandibles dark brown, black at tips, with 
four or more blunt denticles. Maxilla? pale, armed with numerous strong 
spines within. Labium pale. Cervical shield pale brown, with a nar- 
row median longitudinal white line, broadly triangular in shape. 
Jointed legs pale, each with a dark brown chitinous supporting frame- 
work at base ; each segment of legs provided with a number of strong- 
hairs; a single brown tarsal claw, beside which arises a white, elliptical, 
striated plate slightly longer than the claw. Dorsal shield of posterior 
bod v segment nearly- circular in outline, brown, with numerous minute 
black specks, slightly rimmed at posterior margin, and in young examples 
obscurely bituberculate ; furnished witb several strong marginal Hairs, 
and with four minute, striate, centrally placed, spatulate appendages. 
Spiracles round, the two anterior pairs sometimes with brown rims, 
the rest pale. Posterior segment with a single fleshy proleg. 



135 

"Length about .56 inch, diameter about .06 inch. Examples ready 
for pupation about .37 inch long." 

I'ujhi (Plate XIV., Fig. 2 and 3).— "Translucent white, with scat- 
tered brown hairs on dorsal side of body arranged as follows: One 
within, and a pair posterior to, the base of each antenna; a transverse, 
arched row near the anterior edge, a pair near the middle, one at the 
middle of each side, and one at each side, near the posterior margin, 
of the prothorax; four each on the meso- and meta-thorax; three at 
the extremity of each femur; a pair at the middle and one at each side 
of each abdominal segment, except the posterior three; antepenultimate 
and penultimate segments of abdomen each with six, the four inner 
being in pairs and posterior to the others; two within, and three with- 
out each of the large spines borne on the posterior segment. Caudal 
spines straight or curved, black-tipped. Wing-pads covering the pos- 
terior femora below. Antennas curving around the femora of the two 
anterior pairs of legs and then extending inwards towards the ventral 
middle line. 

"Length .22-.2S inch." 

Imago (Plate XIV., Fig. 1). — "Pale green, or greenish yellow, 
marked with black. Head and mouth-parts black, the former showing a 
brownish cast medially on ventral side. Three basal articles of each 
antenna pale, sometimes with dusky dots on posterior side; remainder 
of antennas black. Prothorax uniformly green or yellow. Elytra green 
or yellow, with twelve large black spots, six on each, arranged in three 
cross series ; the first series at the base, the second at about the mid- 
dle, and the third midway between the second and the tips of the elytra. 
Scutellum brown or black. Mesothorax beneath the coxas, the basal 
third to half of femora, and the abdomen, yellow or green. Metathorax 
beneath, the distal portion of the femora, and the whole of the tibia? 
and tarsi, black. 

"Head with a basal pit behind antennae. Prothorax above smooth 
and shining, obsoletely punctulate, with a pair of pits, one on each side 
of the middle line. Margin of prothorax sinuate at sides, no promi- 
nent angles. Elytra minutely, regularly punctulate, each elytron with a 
humeral prominence. Antennas, metathorax beneath, abdomen, and 
legs, clothed with a fine silken pubescence. 

Length .25-28 inch; antenna? about .19 inch." 

c. Roots visibly penetrated and perforated scarcely at all; sometimes 
decayed at tips, bat not eaten away. Principal injury interior, 
in form of minute burrows which are commonly longitudinal. 

THE NORTHERN CORN ROOT WORM. 

(Diabrotica longicornis, Say.) 

(Plate XIV., Fig. 6-8; and Plate XV.) 

The northern or common corn root worm (Diabrotica longicornis) 
is by far the most destructive corn root insect dependent on that plant 
alone. Indeed, it now seems likely that if it were not for the fact that it 
is highly susceptible to a measure of prevention which farmers have very 
generally taken unconsciously, as a part of a sound agricultural routine, 
—10 E 



136 

it would long ago have seriously threatened the profitable continuance 
of corn culture in the very part of the country best adapted to that 
great crop. Even as it is, its injuries are undoubtedly to be reckoned 
by millions of dollars annually*, although the essential facts concerning 
its ravages and their ready and complete prevention were officially and 
widely published nine years agof. 

INJURIES TO CORN. 

The presence of this insect first betrays itself in badly infested 
fields when the plant is a foot or so high. If at this time patches of 
corn are observed which seem to be standing still, so that the plants 
adjacent leave them behind, giving the field an uneven appearance, it 
is possible — especially if the field has been in corn two years or more 
preceding — that this retardation of growth is due to the presence of 
this corn root worm. In this case, if the corn be pulled up, many of 
the larger roots will be seen to be short and stubbed and rotten at the 
ends. On others a deadened brown line will be found, running irregu- 
larly lengthwise, while still other roots may be dead their whole length. 
Possibly when the earth is shaken off a slender white grub will be dis- 
covered, two fifths of an inch long and about as thick as a pin; but 
more frequently the observer must carefully split or peel some of the 
affected roots, when a slender sinuous brown burrow filled with excre- 
ment wil be exposed, running from one end of the root to the other, 
usually with the root worm just mentioned somewhere in its course. 
This grub is white, except the head, the top of the first segment of the 
body, and a little patch on the last segment, which are yellowish brown. 
The body is smooth and cylindrical, the head is short, deep, and rounded, 
and the tip of the body is also bluntly rounded off, somewhat like 
that of a common grub. These last characters will serve to distinguish 
it from small wireworms which are often found in such situations, but 
which are usually flattened from above, especially at the head, while in 
them the end of the body is commonly more or less toothed or notched 
or pointed. The grubs or larvae of several small flies will often be 
found about the roots of corn, and careless or unskilled observers have 
occasionally mistaken these for the corn root worm, but this latter in- 
sect has six short legs on the three segments just behind the head, while 
the grubs of flies are footless. We have seen as many as fifteen or 
twenty to a hill, and I do not doubt that in fields heavily attacked they 
are much more numerous. As the root dies, however, it is forsaken and 
another is attacked, until, not infrequently, almost every root will be- 
come infested as fast as it puts forth. This damage may thus extend 
to the practical destruction of the entire root growth, and the conse- 
quent death of the plant; or it may remain miserably dwarfed, six 
inches, perhaps, when other plants measure four or five feet. If the 
stem is perforated above the roots, the injury is probably due to the 
southern root worm or to some of the species of Avireworms, which one 
can only be told by finding the insect itself. 

* Webster estimates the damage to corn in twenty-four counties of Indiana in 
1885 at two million dollars, basing this judgment on a loss of $16,000 by one large 
farmer, and on his personal knowledge of its distribution and abundance in that 
State. 

t Twelfth Rep. State Ent. 111., pp. 29, 30. 



137 

Attention may perhaps be first attracted when the corn is putting 
forth the silk, by the extraordinary number of barren stalks upon which 
no ear is forming, or stalks may be seen winch have scarcely life enough 
to tassel. It may also be observed that the corn is unaccountably late, 
looking evidently greener and younger than other fields which had no 
advantage at the start. Or injury may be first suspected during a peri- 
od of drouth, patches here and there, or the entire Held, suffering un- 
duly from this cause. The most conspicuous evidence of this injury, 
however, at this stage of growth, is the prostration of the corn after a 
soaking rain with wind, and the evident inability of the plant to right 
itself, if one of the worst affected stalks be pulled up, the observer will 
notice that the roots are few in number, that many of them are with- 
ered and brown, and that others are rotted away to stubs. In these dis- 
colored roots the minute brown burrow of the insect may usually be 
detected, and the corn root worm itself may often be exposed. A minor 
attack frequently has the effect so to retard the ripening of the corn 
that it is not ready for the earliest frosts, and the ear consequently re- 
mains soft and unlit for use; or the loss of roots may have diminished 
the size of the stalk and ear, leaving a small nubbin where a full ear 
might have been expected. 

The injury continues from about the first or the middle of June 
to the last of August. As some of the larvae mature and cease their 
work in the latter half of June, and others not for two months later, 
plants once infested may he freed of the attack, at least in part, by the 
pupation of the root worms, and others, spared at the beginning of 
the season, may become infested later. It has sometimes been observed 
that large, rank stalks which did not ear out had evidently been injured 
after the corn had begun to tassel; while others, which leaned over at 
the root and then grew erect, had been infested earlier in the season but 
had thrown out new roots after the root worms had matured. 

It is a matter of common observation that injuries by this insect 
are most noticeable during dry years and upon the higher parts of the 
field. We have no evidence, however, that the corn root worms them- 
selves are more numerous at such times or in such situations, and the 
greater injury may be due simply to the diminished ability of the plant 
to withstand attack. I have, in fact, seen vigorous and flourishing hills 
of corn badly infested during wet seasons with no visible effect upon 
their growth, even the larger, burrowed roots remaining fresh and effi- 
cient, notwithstanding the injury. 

In case no retardation of growth or damage to the crop has been 
observed, less conspicuous mischief may often be indicated by the great 
abundance in the field, late in July and in August, of a small grass- 
green beetle about a fifth of an inch in length, resembling in shape and 
general aspect the common small striped squash beetle to which, in- 
deed, it is closelv allied. These beetles are most likely to be seen clus- 
tered at the tip of the ear and feeding upon the young silk, or lurkinsr at 
the base of the leaf where it joins the stalk, feeding there upon the fallen 
pollen of the plant. They should also be looked for upon the blossoms 
of ragweed, smartweed, and other nlants in bloom among the corn. 
This is the adult insect to which the corn root worm, so-called, has 
given origin, and its presence in extraordinary numbers in any field of 



138 

corn is presumptive evidence that the plant has suffered earlier consid- 
erable root injury of the character above described. 

It is very rarely that these phenomena are to be observed on ground 
not previously in corn, although sorghum and broom corn have been 
found somewhat favorable to the development of this insect. It is 
only where through neglect it has become enormously abundant in a 
field that we may anticipate its escape from the corn in very large 
numbers before it has laid its eggs, in which event, corn not succeeding 
com may possibly suffer the following year.* The general damage to 
a field is in the worst cases sufficient to destroy the crop so far that the 
disgusted farmer turns his pigs into his corn to get what they can. and 
makes no attempt to harvest his crop. A badly infested field was de- 
scribed to me by Dr. Boardman in 1882, which is worthy of mention 
as illustrating one of the common effects of root injury by this beetle. 
"I should say," he writes, "that one fourth of the corn in this field was 
rotting or beginning to rot. I found, on cutting an ear open, that I 
could slice the cob as easily as if it were a turnip. The infested corn 
[in Stark county] is yielding from ten to fifteen bushels per acre." 

Although the corn root worm beetle is distributed throughout the 
Mississippi Valley, and south even to Central America, it clearly be- 
comes comparatively rare southward, and has never been taken by us in 
Southern Illinois in any numbers, nor found injurious in the larval 
stage except in the northern two thirds of the State, f 

This root worm has not heretofore been certainly found infesting 
any-other plant than corn,J and the amount of skilled attention which 
has been given to this point by entomologists and other accurate ob- 
servers, makes it practically sure that it is so closely limited to corn at 
the present time in Illinois that we may base our economic methods 
upon the supposition that it infests no other plant. 

FOOD OF THE BEETLE. 

The beetles, beginning to appear in June and continuing until 
November, feed entirely during this whole period upon the softer and 
more delicate parts of the vegetation present at the time. They collect 
the pollen from the tassels of the corn, or gather that which has sifted 
down among the leaves and collected at their bases, where these join the 
stalk. They also gnaw away the fresh silk from the tip of the ear 
(where they may often he found congregated in numbers of a dozen 
to twenty, or more), probably thus doing a considerable amount of mis- 

* As an example of this tendency to spread from the infested field, I may note 
the not uncommon occurrence at Rankin, 111., July 1, 1887, of this corn root worm 
in a field of corn following- oats, but only on that part of it which bordered an in- 
fested field in corn the previous year. It is possible that other instances of this 
kind reported previous to 1891 may have related to the southern corn root worm, 
Diabrotica 12-punctata. 

t I now believe that the statement made by me in 1886 (see "Entomologica 
Americana," Vol. II., p. 174) to the effect that I found it injurious to corn in a 
field near Cairo, in Southern Illinois, which had been under water for nearly three 
weeks in the spring-, really referred to the southern corn root worm (Diabrotica 12- 
punctata), of whose habit as a corn root insect nothing was at that time known. 

% A statement from a correspondent, published in my Twelfth Report (p. 19) 
that it is sometimes very abundant in the roots of purslane (Portulaca), I believe 
to have been based on the frequent occurrence in the main root of that plant of the 
burrows of a coleopterous larva resembling the corn root worm, but certainly dif- 
ferent ; although never having bred it, I am unable to identify it precisely. It is 
shorter than Diabrotica, and has the mouth parts black instead of brown. 



139 

chief by destroying the silk before ii has served for the fertilization of 

the -rain, and causing thus a partial blasting of the car. They often 
cat the pollen of smartweed and ragweed anion-- the coin, and outside 
the fields arc very abundant upon thistle blossoms, and likewise upon 
heads of red clover, the pollen and petals of which they feed upon. By 
Professor French, of Carbondale, III., they arc said sometimes to infest 
the bean plant; Or. Boardmanj of Stark county, reported them as 
abundant on cucumber and squash vines, and we have repeatedly seen 
them late in the year (October 11 to December 16) gnawing into ripe 
pumpkins in the field, eating through the outer hard coat, and burying 
themselves in the pulp to a'deptli of nearly half an inch. We have found 
them feeding on flowers of Eelianthus, goldenrod, and other Composite, 
and on the pollen of sorghum and of squash; and Professor Webster lias 
seen them on the blossoms of the cotton plant. A farmer in De Kalb 
county asserts that they eat the pulp of apples where the skin has been 
broken from some other cause, enlarging such injuries so as seriously 
to damage the fruit. Tins same fact was reported to me some years ago 
from Grundy county, by Mr. 0. B. Galusha, then Secretary of the State- 
Horticultural Society, thin-skinned apples apparently suffering worst 
and. according to the judgment of my informant, being thus injured 
without the assistance of other insects. They have been repeatedly de- 
tected by us beneath the husks of ears of corn, where the tips had been 
exposed or injured by birds or grasshoppers, feeding here on the broken 
grains. In one instance the beetle had apparently made its way through 
the husk itself, and was feeding upon the soft grains beneath. By 
Professor Burrill, of the University of Illinois, it was found in 1889 
(September 30) feeding upon a fungus belonging to the genus Phallus; 
and I demonstrated by dissections in 1882 the fact that it sometimes 
feeds largely on the smaller fungi — blights, rusts, etc.* 

LIFE HISTORY. 

This species is single-brooded, as far as known. Although a few 
beetles may occasionally linger late in open winters, — to December 16 
of the present year (1892) for example — and as a rare exception may 
even pass the winter alive, the species hibernates almost invariably as an 
egg in the earth. f As a rule, which is, so far as known, practically 
without exception, these eggs are deposited in fields of corn and hatch 
there the following spring — at just what date has not been precisely 
ascertained. The larvae have first been detected in Central Illinois June 
10. They were found by me less than half grown near Polo, in North- 
ern Illinois, June 14, 1883. As the beetle was reported by an excellent 
observer (Dr. E. R. Boardman) to have occurred one season in south- 
eastern Iowa as early as June 25, some larvae must hatch by the begin- 
ning of that month. Pupation can scarcely begin later than June 20 
if Dr. Boardman's date for the beetle is correct, and the same observer 



* Twelfth Rep. State Ent. 111., p. 23. 

f I have in my office collection two specimens (one male and one female) ob- 
tained March 14, 1883, at Normal, Illinois, with a quantity of miscellaneous insects 
collected from their hibernating quarters. On the other hand, beetles collected from 
pumpkins at Urbana. November 2. 1892, and placed in breeding- cages with pieces 
of pumpkin as food, had died in large numbers by November 20 ; a very few were 
still alive December 4 ; two remained December 17 ; but December 28 all were dead. 



140 

reports the finding of the pupa itself in the earth June 29. On the 
other hand, larvae ready for pupation have occurred in our collections 
as late as August 2(3 — giving a period of something over two months for 
the pupation of an entire generation. 

The extreme dates definitely fixed for the next transformation — 
the emergence of the heetle — are June 25 for the earliest* and not 
earlier than August 31 for the last — again a period of something more 
than two months. We have seen the beetles copulating at various dates 
from July Id to September 25, — an interval of tfro months and six 
days, — observations which probably fix approximately the beginning and 
the end of oviposition. The eggs, however, were not all laid by October 
1, 1882, as I determined by dissecting females at the time. For the 
present we may assign August 1 and October 5 as the average dates for 
the first and last deposit of eggs. 

The recognition of this eight or nine weeks' period for the passage 
of the whole of a brood from one stage to another, enables us to say 
with some assurance that the eggs laid during this long interval in one 
year will hatch through a corresponding interval the year following — 
approximately from May 15 to July 15, or a little later. While these 
dates are, some of them, inferred, there is no doubt of the extension 
of each stage of the development over as long a period as that here 
given ; namely, two months to nine weeks. We have no precise observa- 
tions concerning the length of life of any individual in any one stage; 
neither do we know the number of eggs laid by each female, except 
as an inference from dissections. I have counted as many as fifty well- 
formed eggs of nearly full size in the ovaries of a single female beetle. 

HABITS OF BEETLE AND LARVA. 

The growing larva? remain concealed from view within the roots, 
burrowing, not through the middle but nearer the surface, in a slightly 
sinuous longitudinal direction, sometimes from the stalk outwards, but 
more frequently mining inwards from the outer end of the root. They 
have considerable power of locomotion when removed from their burrows, 
and seem capable of going from one root to another. Indeed, the fact 
that they must concentrate in hills of corn after hatching, demonstrates 
their power of locomotion when still very young. f It is altogether 
likely, consequently, that if a hill of corn is killed by them before they 
have reached maturity, they will be entirely able to search out another. 

When full grown they leave the root preliminary to pupation, 
shortening up and changing to the pupa stage in the dirt close by. At 
this time they may often be found in considerable numbers by pulling 
up infested corn and shaking out the dirt from the roots. The beetles 
emerge from the pupa under ground, and, coming to the surface, most 
commonly crawl up the stalk of corn adjacent. When recently trans- 
formed they are of a pale yellowish color, with scarcely a tinge of green. 
Their first food consists, as already mentioned, of the softer tissues of 
the corn pl ant itself, especially of the silk at the tip of the ear, or the 

* On Dr. Boardman's authority. 
* t -Although their thoracic legs are very short, they are nevertheless functional, 
and the hinder end of the body is provided with a kind of anal proleg', which serves 
as an aid to locomotion. 



141 

pollen from the tassel, or sometimes of the sofi kernels, especially if 
jfrese have been exposed by any injury to the husks. They also spread 
to various blossoming weeds in the Held, and after a time begin to desert 

the eorn Held, scattering elsewhere for food. It is commonly towards 
the last of August thai they are lir-t noticeably frequent on thistle 
blossoms, heads of clover, and other outside blooming plants. They do 
not. however, leave the corn fields generally for some time thereafter, 
but may he found there in greatly diminished numbers at least as late 
as the middle of October.* 

How soon after pairing their eggs are laid we do not now know; 
neither has the process of oviposition ever been directly witnessed. The 

freipieni occurence of dead female beetles (ill Octoher and November) 
ill the earth in corn fields in the midst of the eggs, and the distribution 
of the eggs themselves is, however, sufficient evidence that the beetle 
enters the earth to lay her eggs, and that she may perish there after her 
ovaries are spent. Although the eggs of this beetle have never been 
found outside of corn fields, notwithstanding extensive search in many 
other situations, it is certain that the eggs are not necessarily all laid 
before the female leaves the field in which she emerged. I have, on the 
contrary, frequently proven by dissection of beetles taken from flowers 
by roadsides, in meadows, and the like, that females thus dispersed may 
still contain eggs in large numbers, A considerable part of the beetles, 
and apparently the greater part, do, however, lay their eggs under ordi- 
nary circumstances before they leave the field of corn; and it is also 
highly probable on general grounds that those which go elsewhere in 
search of food return to com fields for oviposition. Since the larva is 
not known to infest any other plant than corn, or, indeed, to be capable 
of living upon any other, it is altogether likely that the female instinc- 
tively searches out the corn plant when seeking a place of deposit for 
her eggs. 

As this is a surmise or inference, however, and not a matter of 
observation, it remains possible that" if the corn root worm is neglected 
it may in time accumulate in such numbers as no longer to confine its 
chief injuries to fields previously in corn, but that the beetles, forced 
to scatter early, in search of food, from the fields in which they emerge 
will deposit their eggs freely everywhere in the ground, instead of being 
confined as now chiefly to corn fields. It is probably in fields of clover 
that this is most likely to occur, since the beetles sometimes become 
abundant there, feeding upon the pollen of the second growth. 

The depth at which the eggs are laid varies from an inch to 'five or 
six inches, the greater part of them being near the surface of the ground. 
They are usually deposited in bunches of three or four to eight or ten, 
within a space' of half an inch across, not in contact with each other, 
nor in any cell or cavity, but always simply scattered in the earth. Most 

* The following is a list of dates, precisely recorded in my office collection 
records, for the occurrence of this beetle : 

In corn fields. July 19 (pairing), 21, 27, 28; August 1, 3, 5, 6. 7, 12, 13, 17 
(pairing), 18, 19, 21, 22, 25 (pairing), 27; September 4, 7, 9, 11, 12, 16. 17. 25 
(pairing), October 1, 7, 13, 14, 18; November 1, 7. 

Outside corn fields. March 14, (1883) ; August 19, 20, 21, 22, 25, 26, 27, 29; 
September 4, 7, 13, 15, 16, 22 ; October 1, 3, 10, 13, 16, 18 ; November 2, 24 ; De- 
cember 1, 16. 



143 

careful examinations made in 1882, and many times repeated, of the 
earth between the rows, and of the roots of all the weeds growing in 
the field, have failed to discover so much as a single egg outside a space 
a few inches across, around each hill. A similar careful search of the 
roots of thistles, ragweeds, and goldenrod outside the fields, upon the 
flowers of which the beetles were feeding in great numbers, had a 
similar result; and we have found no evidence in the roots of these 
plants, either in the corn fields or elsewhere, that they have ever been 
infested by the larva?. In short, not the slightest direct proof has thus 
far been found that the beetle breeds anywhere except in fields of corn. 
It is very probable that a few develop in other situations; but the num- 
ber seems to be so small as to defy discovery, except by accident. 

NATURAL ENEMIES. 

Of natural enemies of this insect, practically nothing is known. 
While in the corn root, the larva is scarcely liable to harm. When 
outside the roots, it has possibly been destroyed now and then by pre- 
daceous insects, which are often numerous in and about hills of corn, 
but dissections of insects of this class (reported in my Twelfth Report), 
do not confirm this supposition. The soft-bodied pupas scattered in the 
earth without special protection of any kind would certainly seem to 
be exposed to insect enemies of this class, but of this fact we have no 
definite evidence. The beetles are not eaten by birds, so far as known, 
and our breeding experiments have yielded no insect parasites.* The 
spent adult, female or male, may become infested before death with 
intestinal parasites (Gregaringe), and we have occasionally found the 
dead bodies yielding a growth of Sporotriclium globidiferum — a fungus 
paiasite of living insects generally distributed everywhere. 

PREVENTION AND KEMEDT. 

A judicious rotation of crops is so simple and complete a preven- 
tive measure, that remedies for injur}'- to corn by the northern corn 
root worm are practically unnecessary. The eggs being laid in corn 
ground in the fall and the larva? hatching the following spring, feeding 
so far as known upon nothing else but corn, the planting of such infested 
land to any other grain must inevitably lead to the starvation of thd 
young when they hatch in spring. This is not an inference from the 
life history of the insect merely but even before the time and place of 
oviposition were known, it had been commonly noticed that corn was 
rarely if ever liable to injury by this insect if planted on ground 
which had borne any other kind of crop the preceding year. I have, 
however, some reason to suppose that sorghum and "broom corn are not 
good crops to follow Avith corn when this root worm is present. 

The frequency of the rotation must depend upon' circumstances, 
and especially upon the general abundance of the insect at the time. I 
know of no part of Illinois in which corn is not safe for at least two 
years, and in many situations another year may be added to this period, 
No field on which the crop has already suffered to any noticeable ex- 

* An assistant, Mr. C. W. Woodworth, reported September, 1885, the finding of 
two small locustids — specimens of which were not broug-ht in — eating the adult Dia- 
brotica. One of these was taken with a half eaten beetle in its jaws. 



143 

tent should be planted to corn the following year; and it will likewise 
be prudent to moid rout inning in corn any field in which the grass- 
green beetle of this species is seen to be abundant in September and Oc- 
tober. 

The only other preventive measure worthy of mention is one 
equally to be commended as a general agricultural practice; namely, 
the maintenance of the fertility of the soil by the use of manures, etc. 
This will not, so far as known, diminish in any way the amount of 
■insect attack, but it will enable the plant to stand a minor injury with 
relatively little loss. It is possible that experiments with various kinds 
of fertilizers will show that some of them, the potash salts for instance, 
may have an immediate deleterious effect^ upon the larvae in the earth, 
but we have at present only a speculative basis for this supposition. 

Description. 

Larva (Plate XIV v Fig. 7; and Plate XV., Pig. 2-8).— The corn 
root worm, when fully grown, just previous to its last moult, is .4 of 
an inch in length by one tenth that width, white and smooth when un- 
der a low power, but when more highly magnified, the skin is seen to 
be minutely roughened with very small tubercles. The body is cylin- 
drical, narrowing a little anteriorly, the first segment being the short- 
est and narrowest of all. There are a few scattered stiff hairs to each 
segment, most numerous anteriorty, and especially upon the head. The 
latter is narrower than the first segment, convex but flattened above, 
about two thirds as wide as long, and smooth except for the hairs al- 
ready mentioned. It is yellowish brown, a little darker in front and at 
the sides beneath. A narrow dark line extends along the middle of 
the head, widest posteriorly, where it is divided by the very narrow 
white suture, which forks at the middle, sending two narrow straight 
branches to the anterior angles of the head. 

Here the short, white, three- jointed antenna? are situated, the first 
joint about twice as wide as the last, and the second joint very short. 
The eyes are wanting. The mandibles are dark, with black tips, and the 
other mouth appendages are white. The thoracic segments all bear 
short two- jointed legs, each about as long as the segment to which it 
is attached. They are pale brown, armed with short, stout spines and 
terminating in a single claw and a flattened, membranous, oval ap- 
pendage, which extends some distance beyond the tip of the claw. The 
top of the first segment is coriaceous and yellowish brown while all the 
others are soft except the last, upon which is a circular brownish patch 
of leathery consistence. Beneath this segment is a prominent retractile 
wart or tubercle, serving as a false leg. The segment is entire and 
rounded posteriorly, where it is set with a few long hairs or slender 
spines. 

Just before pupating, the larva becomes very much shortened and 
thickened, assuming more the form of a common grub. The abdominal 
segments now become much more distinctly marked, and the head takes 
a vertical position. The length in this, which may be called the semi- 
pupa stage, is only about one fifth of an inch, and the greatest breadth 
.045 of an inch. The body now tapers more posteriorly than before. 



144 

the last two segments being conspicuously narrower than the preced- 
ing. In other respects the larva remains unchanged. 

The only objects which I have noticed in the ground about the 
roots of corn, which are likely to be mistaken for the corn root worm, 
are very young earthworms, the larvae or grubs of small gnats and other 
hies, and young wireworms. On a careful examination the first two 
of these may be readily distinguished by the fact that they are en- 
tirely destitute of legs, while, as already remarked, the root worm has 
three pairs of jointed legs just back of the head. In this respect it 
agrees with the young wireworms, which are (also like the root worm) 
destitute of appendages to the other segments of the body. Their crust 
is, however, firmer than that of the latter species, the head is longer, 
flatter, and thinner, the body also usually somewhat flattened and the 
last segment commonly either notched or variously toothed. 

Pupa (Plate XIV. Pig. 8). — The characters of the newly formed 
pupa are well shown by the figure, but as some changes occur previous 
to the escape of the beetle, a description of the latest stage is given. 
The length is .18 of an inch, and the greatest width about .1 of an 
inch. The color is pure white throughout, with the exception of the 
brownish red eyes, which now show through the skin, and a pair of 
brown, horny, curved hooks, attached to the tip of the abdomen about 
equaling in length the preceding segment. The arrangement of the 
wings, wing covers, legs, and antennae, and the position of the head, 
are well shown in the cut. Two white erect hairs are seen between the 
antennae, and another pair above and between the eyes. 

Several scattered slender spines appear. upon the back of the pro- 
thorax, as well as an irregular transverse row upon each of the other 
segments of the thorax and abdomen. These hairs are especially long 
and strong at the tip of the abdomen, and a few likewise appear upon 
the tibio-femoral joints. The hairs, as well as the forceps-like claws at 
the tip of the body, already mentioned, doubtless serve to fix the pupa 
skin in the earth when the beetle emerges. The spiracles are distinctly 
visible as small brown rings upon the back of each of the first eight 
abdominal segments, but upon the three remaining segments posterior 
to these they are not apparent. 

Imago (Plate XIV., Fig. 6). — The adult beetle is about one fifth 
of an inch in length by about half that in breadth, and a little widest 
posteriorly. Its head is nearly as wide as the thorax, smooth, or nearly 
so, with a large circular depression between the eyes, from which a 
narrow groove leads forward, dividing between the antennae and en- 
closing between the branches of the fork an elevated ridge, which ex- 
tends downward to the labrum. On either side of this, and in front of 
each antenna, the surface is minutely rugulose. There is also an angu- 
lar depressed line just within each eye. The antennae are rather long, 
extending backwards beyond the middle of the elytra. The second and 
third joints are short and equal, and together about as long as the 
fourth. The remaining joints of the antennae are of nearly equal 
length. The first and second joints are nearly smooth, the remainder 
pubescent. The eyes are black, the head and first joint of the antennae 
are pale brown or green or brownish green, and the rest of the; an- 
tennae, the labrum, and mouth parts brown. 



115 

The thorax is nut as wide as the elytra, and is strongly narrowed 
behind the middle, making the margin sinuate. The anterior angles 
arc rounded and the posterior obtuse. The sides of the thorax are nar- 
rowly expanded and recurved, Leaving a gutter-like margin along the 
whole length. It is not margined behind. The disk is very slightly 
pubescent, and sparsely and faintly punctured, most distinctly poste- 
riorly. A little behind' the middle, upon each side of the median line, 
is a Large conical fovea, bu1 there is ao median ridge or groove. A 
strong, erect hair occurs in front of the posterior angle, and another 
behind the anterior, and two or three short hairs follow the Latter. 

The elytra are coarsely and irregularly punctured, and sparingly 
pubescent, with short si ill' hairs. The surface is diversified by four or 
five obscure and irregular ribs, of which the outermost is largest, and 
forms a well-marked longitudinal angle. This and the one next it unite 
anteriorly in a prominent humerus. The edge of the elytron is recurved 
like that of the thorax, forming a still deeper gutter just within the 
margin. 

The thorax and elytra are commonly brownish green or grassy 
green throughout, but the humeral angles are occasionally touched with 
brown, as is likewise the smooth scutellum. The sutural line is also 
sometimes brown. The epipleura 3 are green, and do not attain the tips 
of the elytra. The legs and under surface of the body are puhescent ex- 
cept the prosternum, which is smooth, or nearly so. The ahdomen is 
sparsely punctured. The thighs are usually green, but the tibiae, the 
tarsi, and the sides of the metasternum are more or less deeply tinged 
with brown. 

Egg (Plate XV., Fig. 1). — The egg is of a dirty Avhite color and 
very minute, .025 of an inch in length and .015 of an inch wide ; nar- 
rower at one end than at the other, having in fact almost precisely the 
shape of a hen's egg. Under the microscope the surface is seen ito be 
thickly dotted with minute hexagonal pits, about twenty in its entire 
length, and under a higher power the bottom of each of these pits ex- 
hibits still more minute depressions, seven or eight to each reticulation. 



140 



EXPLANATION OF PLATES. 



PLATE I. 



Fig. 1. Myrmica scabrinodis lobicornis, female; enlarged ten diameters. 
Fig. 2. Male of same species; enlarged nine and one fourth diameters. 

PLATE II. 

Fig. 1. Myrmica scabrinodis lobicornis, worker; enlarged eight and one 
half diameters. 

Fig. 2. Solenopsis debilis, worker; enlarged eighteen diameters. 

Fig. 3. Agonoclerus pallipes, imago; enlarged four and one fourth diam- 
eters; its work in seed corn. 

Fig. 4. Aphodius granarius, imago; enlarged six and one half diameters. 

Fig. 5. Clivina impressifrons, imago; enlarged eight and one half diam- 
eters. 

Fig. 6. The Seed-corn Maggot, Phorbia fusciceps, larva, enlarged eleven 
diameters. 

Fig. 7. Puparium of same, enlarged ten and one half diameters. 

PLATE III. 

Fig. 1. The Seed-corn Maggot, Phorbia fusciceps, imago; enlarged eight 
and two thirds diameters. 

Fig. 2. Seed-corn injured by larva of the same. 

Fig. 3. The Black-headed Grass Maggot, Sciara sp., enlarged five diam- 
eters. 

Fig. 4. Labrum of same, upper surface. 

Fig. 5. Labrum, lower surface. 

Fig. 6. Mandible. 

Fig. 7. Maxilla. 

Fig. 8. The Pale-striped Flea-beetle, Systena, Ueniata, imago; enlarged 
ten diameters. 

PLATE IV. 

Fig. 1. The Pale-striped Flea-beetle, Systena Ueniata, larva; enlarged 
nineteen diameters. 

Fig. 2. Side view of same. 

Fig. 3. The Banded Ips, Ips fasciatus, larva; enlarged eight and one 
third diameters. 

Fig. 4. Pupa of same; enlarged nine diameters. 

Fig. 5. Imago of same; enlarged eight diameters. 

Fig. 6. Cardiophorus sp., larva, dorsal view; enlarged four diameters. 

PLATE V. 

Fig. 1. Drasterius elegans, imago; enlarged seven and one half diam- 
eters. 

Fig. 2. Larva of same; enlarged seven diameters. 

Fig. 3. Caudal segment of larva, more enlarged. 

Fig. 4. The Wheat Wireworm, Agriotes mancus, imago; enlarged seven 
diameters. 



147 

Fig. 5. Larva of same, enlarged five diameters. 
Fig. 6. Side view of same. 

PLATE VI. 

Fig. 1. Agriotes pwbescens, imago; enlarged six diameters. 

Fig. 2. Melanotus ftssilis. imago; enlarged three and four fifths diam- 
eters. 

Fig. 3. Melanotus communis, imago; enlarged four diameters. 

Fig. 4. Side view of a middle segment of larva of same species, show- 
ing muscular impression, spiracle, etc. 

Fig. 5. Caudal segment of same, dorsal view; greatly enlarged. 

Fig. 6. The Corn Wireworm, Melanotus cribulosus, larva; enlarged 
four diameters. 

Fig. 7. Side view of a middle segment of same. 

Fig. 8. Caudal segment, dorsal view; greatly enlarged. 

PLATE VII. 

Fig. 1. The Corn Wireworm, Melanotus cribulosus, imago; enlarged 
four and a half diameters. 

Fig. 2. Asaphes decoloratus, imago; enlarged four and one fifth diam- 
eters. 

Fig. 3. Larva of same, dorsal view; enlarged three and three fourths 
diameters. 

Fig. 4. Caudal segment of same; more enlarged. 

Fig. 5. The Corn Root Aphis, Aphis maidiradicis, oviparous female; en- 
larged fourteen diameters; a, Kind tibia, showing sensoria. 

Fig. 6. Male of same species; enlarged twenty-five diameters; a, an- 
tenna. 

PLATE VIII. 

Fig. 1. The Corn Root Aphis, Aphis maidiradicis, wingless viviparous 
female; enlarged fourteen diameters; a, apex of abdomen showing cornicles, 
tubercles, and cauda. 

Fig. 2. Antenna of same. 

Fig. 3. Pupa of same species; enlarged twenty-one diameters. 

Fig. 4. Winged viviparous female of same species; enlarged sixteen 
diameters. 

Fig. 5. Antenna of same. 

Fig. 6. The Grass Root Louse, Schizoneura panicola, winged viviparous 
female; enlarged eighteen diameters; a, antenna. 

PLATE IX. 

Fig. 1. The Grass Root Louse, Schizoneura panicola, wingless viviparous 
female; enlarged twenty-nine diameters. 

Fig. 2. Trama erigeronensis; enlarged twenty diameters; a, antenna; 
b, beak; c. cauda. 

Fig. 3. Forda occidentalis; enlarged twenty-one diameters; a, antenna, 
b, beak; c. cauda. 

Fig. 4. Tychea brevicornis; enlarged twenty-two diameters; a, antenna, 
b, beak. 

Fig. 5. Oeoica squamosa, wingless viviparous female; enlarged twenty- 
three diameters. * 

Fig. 6. Structures of same; a, beak; b, antenna; c, tarsus. 

PLATE X. 

Fig. 1. Geoica squamosa, pupa; enlarged twenty-four diameters. 
Fig. 2. Winged viviparous female of same species, antenna. 



148 

Fig. 3. Wing of same. 

Fig. 4. The Woolly Grass Root Louse, Rhizobius spicatus ; enlarged 
twenty-six diameters; a, antenna; b, beak. 

Fig. 5. The Small Brown Ant, Lasius niger alienus, female; enlarged 
four and one half diameters. 

Fig. 6. The same, worker, enlarged eight and one fourth diameters. 

Fig. 7. The Corn Mealy Bug, Dactylopius sorghiellus, adult female, dor- 
sal view; enlarged twenty-nine diameters. 

Fig. 8. The same, ventral view. 

PLATE XL 

Fig. 1. The Small Brown Ant, Lasius niger alienus, male; enlarged 
eight and one fourth diameters. 

Fig. 2. Formica schaufussi, worker; enlarged eleven and one half diam- 
eters; a, portion of upper surface of abdomen greatly enlarged. 

PLATE XII. 

Fig. 1. Lachnosterna rugosa, male imago; enlarged two and one fifth 
diameters; a, last two ventral segments. 

Fig. 2. Larva of same; enlarged two and one half diameters. 

Fig. 3. Lachnosterna rugosa or hirticula, last abdominal segment of 
larva, seen from beneath; enlarged six diameters. . 

Fig. 4. Lachnosterna fusca, male imago; enlarged two diameters; a, 
last two ventral segments. 

Fig. 5. Lachnosterna inversa or fusca, last abdominal segment of larva, 
seen from beneath; enlarged six diameters. 

Fig. 6. Lachnosterna gibbosa, male imago; enlarged two diameters; 
a, last two ventral segments; b. spurs at tip of hind tibia. 

Fig. 7. Larva of same, last abdominal segment; seen from beneath; 
enlarged six diameters. 

Fig. 8. Cyclocephala immaculata, last abdominal segment of larva, seen 
from beneath; enlarged six diameters. 

PLATE XIII. 

Fig. 1. Cyclocephala immaculata, larva; enlarged three and one third 
diameters. 

Fig. 2. Imago of same; enlarged three diameters. 

Fig. 3. Prionus imbricornis , imago; natural size. 

Fig. 4. Prionus laticollis, imago; natural size. 

Fig. 5. Prionus, larva; natural size. 

Fig. 6. Prionus, pupa; natural size. 

Fig. 7. The Green June Beetle, Allorhina nitida: a, larva; b, pupa; c, 
male imago; all enlarged one and a half, diameters; d, e, f, g, mandible, 
antenna, leg, and maxilla of larva; more enlarged. 

PLATE XIV. 

Fig. 1. The Southern Corn Root Worm, Diabrotica 12-punctata, imago; 
enlarged five and two thirds diameters. 

Fig. 2. Pupa of same, dorsal view; enlarged ten diameters. 

Fig. 3. Ventral view of pupa. 

•Fig. 4. Larva of same, dorsal view; enlarged five diameters. 

Fig. 5. Side view of larva. 

Fig. 6. The Northern Corn Root Worm, Diabrotica longicornis, imago; 
enlarged ten diameters. 

Fig. 7. Corn root broken across to show larva of same within. 

Fig. 8. Pupa of same; enlarged eight and a half diameters. 



149 



PLATE XV. 

Fig. 1. The Northern Corn Root Worm, Diabrotica longicornis, egg; 
enlarged eighty diameters. 

Fig. 2. Larva of same; enlarged six diameters. 

Fig. 3. Head of larva, dorsal view; greatly .enlarged. 

Fig. 4. Labrnm and leg of larva. 

Fig. 5. Mandible of larva, seen at right angles to cutting edge. 

Fig. 6. The same, seen obliquely from side. 

Fig. 7. The same, seen directly from side. 

Fig. 8. Mouth parts of larva, seen from beneath. 



NOTE. 



The following figures are from drawings made by Miss Lydia M. 
Hart: PI. I; pi. II, fig. 1, 2, 4-7; pi. Ill, fig. 1, 8; pi. IV, fig. 3-5; 
pi. V, fig. 3, 4; pi. VI, fig. 1-3; pi. VII, fig. 2, 5, 6; pi. VIII, and IX; 
pi. X, fig. 1-4, 6-8; pi. XI, fig. 2; pi. XII, fig. 1, 3-8; pi. XIV, fig. 1. 
The drawings for pi. IV, fig. 1, 2, 6 ; pi. V, fig. 1, 2, 5, 6 ; pi. VI, fig. 
4-8; pi. VII, fig. 3, 4; pi. X, fig. 5 ; pi. XI, fig. 1; pi. XII, fig. 2; pi. 
XIII, fig. 1, 2 ; and pi. XIV, fig. 2-5, were by Mr. M. Westergren ; and 
those for pi. XV, fig. 3-8, by Mr. H. Garman. PI. II, fig. 3 ; pi. Ill, 
fig. 2; and pi. XIII, fig. 3, are from Dr. C. V. Eiley; and pi. Ill, 
fig. 3-7 ; pi. XIII, fig. 4-7 ; pi. XIV, fig. 6-8 ; and pi. XV, fig. 1, 2. 
"are reprinted from previous reports of this office. 



Plate I. 




Fig. 1. 




Fig. 2. 



Plate II. 











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Fig. 2. 





Fig. 4. 




Fig. 5. 



Fig. 6. 



Plate III. 




LAjd 



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Fig, 4. 






Fig. 6. 





Fig. 8. 



Plate IA t . 



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V 




Fig. 3. 




Plate V. 




W™Wm ^^y^ r A4 





Fig. 3. 




Pig. 5. 



Plate VI. 







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Fig 7. 



a; ;i 



V 



i \ 



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Fig. 3. 




Fig. 



Plate VII. 




Fis. 4. 









Fig. 5. 




Plate VIII. 



Y 






Fig. 1. 



Fig. 2. 





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Fig. 5. 




Fig. 



Plate IX. 



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n 



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Fig. 2. 



Fig. 3. 




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Plate X. 




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Kpoo^ 




Fig. 



Fig. 2. 



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Fig. 4. 




Fig. 3. 



Fig. 7 



o 



I i X 



Fig. 8. 




Plate XI. 





Fig. 2. 



Plate XII. 





Fig. 2. 




Fig. 3. 





Plate XIII. 






Fig. 4 




Plate XIV. 




Fig. 



Plate XV. 



A.T/n,> 



Fig. 1. 




Fig. 3. 




Fig. 4. 



Fig. 2. 




Fig. 




Fig. 




INDEX. 



achyrantes, Myzus, 4S. 
affinis, Lachnosterna, 123. 125. 
Agonoderus" comma, 11. 
pallipes, 7, 11. 

description. 12. 
food of, 11. 
Agriotes. 27, 28. 

mancus, 7. 20. 32-34, 47. See under 

Wheat Wireworm. 
pubescens, 7, 34, 47. 
Agrypnus, 27. 
Ala us, 27. 

albifrons. Edema, X. 
Alice Thrush as enemy of Wireworms, 

41. 
alienus, Lasius niger, 46, 54, 57, 58, 62, 

69, 72, 79, 94, 95. 
Allorhina nitida, 47, 127. See under 

Green June Beetle. 
Amarantus, 28. 

as food of Pale-striped Flea-beetle. 

19. 
hybridus infested by Corn Root 
Aphis. 53. 
Ambrosia as food of Corn Root Aphis, 
53. 
as food of Pale-striped Flea-beetle, 
19. 
americanus, Ceanothus, 101. 
Lasius niger, 72. 
Melanotus, 28. 
anisoplise. Metarrhizius, 41. 
Anthomyia zeas, 14. 

Ants, 45, 46, 48, 51, 57, 67, 69, 79. 119. 
as enemies of White Grubs, 110. 
attendant on Forda occidentalis, 
84. 
on Geoica squamosa, 87, 88, 89. 
on Grass Root Louse, 79. 
on Sorghum Mealy Bug, 94. 
on Trama erigeronensis, 82. 
destruction of nests, as measure 
against Corn Root Aphis, 66, 68. 
food of, 74. 
injuries by, 7-10. 
insects found in nests of. 88. 
relation to Corn Root Aphis. 57. 

to Grass Root Louse, 79. 
White, note of injuries at State 
House, X, 
Aphidida? and Coccidae, 48-95. See un- 
der Plant Lice and Mealy Bugs. 
Aphis, Corn Root. 46. 50-75. See under 
Corn Root Aphis. 
maidiradicis. 8, 46, 50-75, 92. See 

under Corn Root Aphis, 
maidis, 49. See under Corn Leaf 

Aphis, 
mali, 49. 

food plants, 49. 
Aphodius, 12. 

granarius, 7, 12. 

description, 13. 
lutulentus, 12. 



Apple leaves as food of May Beetles, 101. 

louse, 49. 

food plants, 49. 
roots of, subject to attack by 

Prionus Grubs, 128. 
trees, young, damaged by larva of 
Cecropia Moth, X. 
Apples as food of adult Northern Corn 
Root Worm, 139. 
injured by adult Banded Ips, 21. 
by large Flea-beetle, X. 
Apricot leaves as food of adult South- 
ern Corn Root Worm, 131. 
arcuata, Lachnosterna, 122, 125. 
Army Worm, X, 3, 50. 
Arsenic for Wireworms, 43. 
Arsenical poisons for Agonoderus pal- 
lipes. 11. 
solutions, effect on Seed-corn, 43. 
for June Beetles, 113, 116. 
Asaphes, 28, 41. 

decoloratus, 7. 26, 39, 47. 
description, 40. 
life history, 39. 
Ash leaves as food of May Beetles, 101, 
105. 
Mountain, leaves of, as food of May 
Beetles, 101. 
Ashes, wood, for Corn Root Aphis, 67, 

Ashmead, W. H., 30. 
Athous, 28. 

australis, Ceratochloa, 82. 
avenge, Siphonophora, 49. 



Bacillus rufans, appearance of larvae in- 
fested by, 132. 
description, 133. 
mode of growth, 133. 
parasite of Southern Corn Root 
Worm, 132. 
Bacterial disease of Corn roots, 45. 
of White Grubs, 111. 112. 
parasite of Southern Corn Root 
Worm, 132. 
Badgers as enemies of White Grubs, 109. 
balia, Lachnosterna. 123, 126. 
Banded Ips, 7, 18, 20-24. 
description, 22. 
feeding habits, 21-22. 
life history, 22. 
Barley as breeding place of Chinch Bug, 
IX. 
liable to injury by White Grubs, 
100. 
by Wireworms, 26. 
Barred Owl as enemy of White Grubs, 

108. 
Basswood leaves as food of May Bee- 
tles, 101. 
Bean plant infested by adult Northern 

Corn Root Worm. 139. 
Beans as food of adult Southern Corn 
Root Worm, 131. 
of Pale-striped Flea-beetle, 19. 



Bears as enemies of White Grubs, 109. 
Beetle, Green June, 47, 127. See under 
Green June Beetle. 
Small-striped Squash, 137. 
Beetles, Click, 26, 34. 
Ground, 65. 
injuries by, 7, 10-13. 
June, 96. See under White Grubs. 
Long-horned, 128. 

May, 96. See under White Grubs, 
popular description, 10. 
predaceous, 133. 
Beets as food of Pale-striped Beetle, 19. 
of White Grubs, 96, 100. 
of Wireworms, 26. 
bifoveolatum, Ophion, 110. 
bipartita, Laehnosterna, 122, 125. 
Birch leaves as food of May Beetles, 

101, 102. 
Birds, 139. 

as enemies of Myrmica scabrinodis 
lobicornis, 9. 
of White Grubs, 108. 
of Wireworms, 41. 
Bisulphide of carbon for Wireworms, 44. 
Black Flea-beetle, VII. 

headed Grass Maggot, 6, 7, 14, 16. 
description, 17-18. 
food habits, 16. 

mining flower bulbs, 17. 
Locust leaves as food of May 

Beetles, 101, 
Walnut leaves as food of May 
Beetles, 101. 
Blackberries injured by adult Banded 

Ips. 21. 
Blackberry leaves as food of Pale- 
striped Flea-beetle, 19. 
Blackbird, Crow, as enemy of White 

Grubs, 109. 
blanda. Systena tseniata, 20. 
Bluebird as enemy of White Grubs. 108. 
Blue grass infested by Forda occiden- 
tal is, 84. 
by Geoica squamosa, 87, 88. 
by Grass Root Louse, 77, 78. 
by Trama erigeronensis, 82, 
leaves eaten by Laehnosterna 

beetles, 101. 
root-lice colonized upon, bv Ants, 78. 
Jay as enemy of White Grubs, 109. 
Boardman, E. R., 17, 138. 139, 140. 
Botrytis tenella, 118, 119. 

infesting European White 

Grubs, 112, 117. 
spores of, used for infection of 
White Grubs, 117, 118, 119. 
Box Elder leaves as food of Mav Beetles, 

101. 
Brassica nisra, infested by Corn Root 

Aphis, 53. 
brevicornis. Tychea. 46, 50, 86, 89. 
brevipes. Polvmoechus. 117. 
Broad-winged Hawk as enemy of White 

Grubs, 108. 
Broom-corn, 142. 

favorable to development of North- 
ern Corn Root Worm, 138. 
infested by Corn Leaf Aphis, 60. 
seldom iniured by Corn Root Aphis, 
52, 60. 
Brown Thrush as enemy of White Grubs, 
108, 109. 
of Wireworms, 41. 
Buckman, Benjamin, 17, 21. 
Buckton, G. B., 48, 89. 
Buckwheat and Wireworms, 43. 
Buprestidae, 27. 
Burrill. T. J., 45. 133. 139. 
bursa-pastoris, Capselia, 84. 



Butternut, 114. 

leaves as food of May Beetles, 101. 



Cabbage as food of adult Southern Corn 
Root Worm, 131. 

decaying, eaten by Banded Ips, 21. 

eaten by Wireworms, 26. 
camurellus, Crambus, X. 
canadense, Erigeron, 53. 
Capselia bursa-pastoris infested by 

Forda occidentalis, 84. 
Carabid larvae as food of Lasius niger, 

74, 
Cardiophorous sp., 7, 24, 25, 27, 28, 30, 

47. 
Carnations injured by Wireworms, 26. 
carnosa, Endeis, 89. 
carolinense, Solanum, 131. 
Carrots injured by Wireworms, 26. 
earyse, Halesidota, X. 
Catbird as enemy of White Grubs, 108, 
109. 

adult Southern Corn Root Worm 
eaten by, 134. 
Caterpillars as food of Lasius niger, 74. 

Forest, defoliating Oak and Hick- 
ory, X. 
Cauliflower as food of adult Southern 

Corn Root Worm, 131. 
Ceanothus americanus as food of Laeh- 
nosterna rubiginosa, 101. 
Cebrio, 27. 
Cebrionini, 27. 

Cecidomyia leguminicola, X. 
Cecropia Moth, larva, damaging young 

Apple-trees, X. 
Cerambycidse, 128. 
Ceratochloa australis infested by Sehizo- 

neura venusta, 82. 
Chaetocnema pulicaria, attack on young 

corn, VII. 
Chaitophorus flavus, 61, 63. 
Chalcolepidius, 27. 
Chenopodium as food of Pale-striped 

Flea-beetle, 19. 
Chermesinse, 93. 

Cherry leaves as food of adult Southern 
Corn Root Worm, 131. 
as food of May Beetles, 101. 
Chestnut leaves as food of Mav Beetles, 

101, 105. 
Chickens as enemies of White Grubs, 

109. 
Chinch Bug, 3, 45, 46, 50. 

as food of Agonoderus pallipes, 11. 
of Lasius niger, 74. 

breeding places most acceptable to. 
VIII. 

distribution of infection material 
for, IX. 

field notes and correspondence con- 
cerning. VII-IX. 

in 1890 and 1891, VII-X. 

noticeable feature of injury, VIII. 

outline of area infested by, VII, 
VIII. 

relative damage to crops. VIII, IX. 

white fungus of, IX, 111-112, 119. 
spores used to infect White 
Grubs, 119. 
Chlaenius tomentosus as enemy of Mav 

Beetles, 111. 
Chuck-will's Widow as enemy of White 

Grubs, 109. 
Click Beetles. 26, 34. 

as food of Birds, 41. 
Clivina impressifrons. 7, 13. 
description, 13. 



Clover, 26, 112. 

as food of Pale-striped Flea-beetle, 

19. . . 

in rotation as measure against 

White Grubs, 113. 
blossoms as food of adult Southern 
Corn Root Worm, 131. 
as food of May Beetles, 101. 
infested by Geoica squamosa, 88. 

bv Sorghum Mealy Bug, 94. 
rarely damaged by White Grubs, 

100. 
Red, heads of, as food of adult 
Northern Corn Root Worm, 139, 
141. 
Seed Midge, X. 
Coal-tar, 67. 
Coccidse, 93. 

and Aphididse, 48-95. 
Coceinellid larva; in nests of Ants, 88. 
Coccus sorghiellus, 94. 
Cockchafer Grub, 97. 
Cockchafers, 114, 115. See under White 

Grubs. 
Cocklebur, 28. 

as food of Pale-striped Beetle, 19. 
infested by Sorghum Mealy Bug, 94. 
Coleopterous larva infesting roots of 

Purslane, 138. 
comma, Agonoderus, 11. 
communis. Melanotus. 7. 28, 34, 36, 37, 

38, 39, 17. 
Composita?, flowers of, as food of adult 

Northern Corn Root Worm, 139. 
Comstock, J. H., 31, 32. 
Comstock, J. H., and Slingerland, M. V., 

30. 31, 33, 34, 36. 40, 41, 42, 43. 
Cone-flower roots, pupse of Southern 

Corn Root Worms among, 130. 
congrua, Lachnosterna, 122, 123, 124. 
Copperas and chloride of lime solution 
for protecting Seed-corn, 43. 
solution for protecting same, 43. 
Cordyceps, 41. 

melolontha? as parasite of White 
Grubs, 111, 120. 
Corn Bill Bugs, 5. 

classification of injuries to, 6. 
indications of injury, 4. 
injuries to the roots, 45. 

detailed discussion, 48-145. 
synopsis of, 46. 
to the seed in the earth, 6-44. 
synopsis of above, 7. 
Leaf Aphis, 65. 

characters distinguishing 
from Corn Root Aphis, 

disappearance in fall, 64. 
earliest appearance of. 61. 
relation to Corn Root 

Aphis, 60. 
transfer to roots of other 
plants, 65. 
Mealy Bug. 46. See Sorghum Mealy 

Bug. 
number of insect species injuring. 3. 
Plant-lice, 45. See under Plant-lice. 
Root Aphis. 4, 45, 46, 48. 50-75. 

Ants attendant upon, 72-75. 
autumnal brood, food 

plants, 56. 
description, 70. 

characters distinguish- 
ing from Aphis 
maidis, 72. 
distribution, 51. 



30, 4S, 129, 
See under 
Corn Root 



and 



Corn Hoot Aphis — Continued. 

economic' measures, bo-<u. 
breaking up nests of 

Ants, 68. 
starvation experiments, 

69. 
summary, 70. 
fertilizers and insecticides 

for, 66. 
fungus disease, 65. 
injury to other plants than 

corn, 52. 
life history, 54, 
migration to uninfested 

fields, 56. 
natural enemies, 65. 
number of generations, 55. 

of moults, 56. 
rank as a Corn pest, 50. 
rate of multiplication, 06. 
relation to Ants, 57-60. 

to Corn Leaf Aphis, 
60-65. 
transfer to leaf of Corn, 62. 
blight, 4, 45, 46, 52. 
lice, 3, 45, 46, 48, 50. See un- 
der Plant-lice. 
Louse. See under Corn Root 

Aphis. 
Web-worms, 5. 
Worm, Northern, 
135-145. 
Northern 
Worm. 
Southern, 47, 129-135. See 
under Southern Corn 
Root Worm. 
Worms, 3, 5, 45, 50. 
synopsis of injuries to roots, 

order of discussion, 46. 
Wireworm, 7, 18, 37-39, 47. 
description, 38. 
hibernation, 38. 
length of larval life, 3S. 
relative abundance, 3, 7. 
Worm, 5, 21. 
corni, Schizoneura, 49, 75, 79. 
Cornus as food plant of Schizoneura 

corni, 79. 
corrosa, Lachnosterna, 123, 126. 
Corrosive sublimate for Wireworms, 43. 
Corymbites, 28. 
Corymbitini, 27, 
Cosmos, petals of, as food of Southern 

Corn Root Worm, 131. 
Cotton-plant blossoms as food of adult 
Northern Corn Root Worm, 
139. 
as food of adult Southern Corn 
Root Worm, 131. 
Crab-grass infested by Corn Root Aphis, 

53 - 
by Woolly Grass Root Louse, 92. 
Crarribus camurellus damaging lawns, X. 
crassissima. Lachnosterna, 122, 125. 
crenulata, Lachnosterna, 102, 123, 127. 
cribulosus. Melanotus, 7, 18, 28. 37, 47. 
crispus, Rumex, 53, 65. 
Crow as enemy of White Grubs, 109. 

Blackbird as enemy of White Grubs, 

109. 
as enemy of Wireworms, 42. 
crus-galli, Panicum, 88. 
Cryptohypnus, 2S. 

Cucumber vines infested by Northern 
Corn Root Worm, 139. 
as food of adult Southern Corn Root 
Worm, 131, 134. 
Cutworms, 3, 5, 44. 



Cyclocephala and Green June Beetle 
larvae contrasted, 127. 
and Lachnosterna, 96-127. See un- 
der White Grubs, 
description of larva, 121. 
life history, 107. 
immaculata, 47, 97, 100, 107. 
food of larva, 102. 
leaves of trees rejected by adult, 
102. 
Cyperus strigosus infested by Southern 
Corn Root Worm, 130. 



Dactylopius, 48, 59, 94. 
in nests of Ants, 88, 
sorghiellus, 46, 94-95. See under 
Sorghum Mealy Bug. 
Dahlias injured by Wireworms, 26. 

petals of, as food of Southern Corn 
Root Worm, 131. 
debilis, Solenopsis, 7, 8, 46, 57, 88, 89. 
decoloratus, Asaphes, 7, 26, 39, 47. 
densa, Isaria, 112, 117. 
Dexidae, 110. 

Diabrotica 12-punctata, 47, 129-135, 138. 
See under Southern Corn Root 
Worm, 
longicornis, 30, 48, 129, 130, 135- 
145, See under Northern Corn 
Root worm. 
Dipterous parasites of Southern Corn 
Root Worm, 133. 
of White Grubs, 110. 
Diseases of European White Grubs, 112. 
See also under Bacterial and Fun- 
gus. 
Disonycha pennsylvanica injuring Ap- 
ples,, X. 
Dock infested by Corn Root Aphis, 53, 

65. 
Dogwood as food plant of Schizoneura 
corni, 75, 79. 
of Schizoneura panicola, 49. 
Dolopius, 27. 

Dor-bugs, 96. See under White Grubs. 
Drasterius, 27, 30. 

elegans, 7, 25, 26, 29, 47. 
description 30. 
injurious to Wheat, 29. 
places of hibernation, 31. 
dubia, Lachnosterna, 122, 125. 
Ducks as enemies of White Grubs, 109 
12-punctata, Diabrotica, 47, 129, 138. 



Earthworms, 144. 

Edema albifrons and Halesidota ca- 

ryse defoliating Oak and Hick- 
ory, X. 
Eggs of Agonoderus pallipes, 11. 
of aphides, 49, 78. 
of Apple Louse, 49. 
of Black-headed Grass Maggot, 17. 
of Corn Root Aphis, 53, 54, 55, 56, 

57, 58, 59, 60, 66, 69, 71. 
of Drasterius elegans, 31. 
of Geoica squamosa, 87, 89. 
of Green June Beetle, 127. 
of Lachnosterna rugosa, 99. 
of Lasius niger and its var. alie- 

nus, 72, 73. 
of Locusts as food of White Grubs, 

101. 
of May Beetles, 96, 97, 99, 102, 104, 

105, 106, 107, 112, 113. 
of Myrmica scabrinodis lobicornis, 

10. 



Eggs — Continued. 

of Northern Corn Root Worm, 138, 
139, 140, 141, 142. 

of Sorghum Mealy Bug, 95. 

of Southern Corn Root Worm, 131, 
132. 

of Wireworms, 26. 
Elater, 27. 

Elateridae, 24-44. See under Wire- 
worms. 
Elaterini, 27. 

elegans, Drasterius, 7, 25, 26, 29, 47. 
Elm leaves as food of May Beetles, 101, 

105. 
Endeis carnosa, 89. 

Engerling, 97. See under White Grubs. 
English Sparrow, 134. 

as enemy of White Grubs, 108. 
Entomophthora fresenii infesting Corn 

Root Aphis, 65, 
ephilida, Lachnosterna, 102, 122, 124. 
Eragrostis megastachya infested by 

Schizoneura venusta, 82. 
Erigeron canadense infested by Corn 

Root Aphis, 53. 
erigeronensis, Trama, 46, 50, 82. 
Eucneminae, 27. 
Evergreens infested by White Grubs, 96, 

100. 



farinalis, Pyralis, X. 
fasciatus, Ips, 7, 20. 
Fernald, C. H., 12. 

Fertilizers, 12, 44, 65, 66, 67, 113, 116, 
143. 
and insecticides for Corn Root 
Aphis, 66. 
Fisher, A. K., 108. 

fissilis, Melanotus, 7. 25, 34, 36, 41, 47. 
Fitch, Asa, 26, 35, 42, 60. 
flavus, Chaitophorus, 61, 63. 

Lasius, 79. 
Fleabane infested bv Corn Root Aphis, 

53. 
Flea-beetle, Black, attack on young 
Corn, VII. 
injuring Apples, X. 
Pale-striped, 7, 18-20. See under 
Pale-striped Flea-beetle, 
fluviatilis, Scirpus, 130. 
Forda occidentalis, 46, 50, 84-85. 

description, 84. 
Forel, Auguste, 9. 

Forest Caterpillars defoliating Oak and 
Hickory, X. 
trees infested by White Grubs, 96, 
100. 
roots of, subject to attack by 
Prionus Grubs, 128. 
Formica fusca, 46, 57. 

gagates attendant on Forda oc- 
cidentalis. 84. 
on Geoica squamosa, 
87, S9. 
schaufussi, 46, 57. 

attendant on Grass Root Louse, 
79. 
Formicidae, 9. 

Fowler's solution for Wireworms, 43. 
Foxtail-grass as food of Corn Root 
Aphis, 53. 
destroyed by White Grubs, 99. 
fraterna, Lachnosterna. 123, 126. 
French, G. H, 139. 
fresenii, Entomophthora, 65. 
Fribourg & Hesse, 118. 
Frogs as enemies of May Beetles, 111. 
Fruit-trees, young, infested by White 

Grubs, 96, 100. 
fugax, Solenopsis, 8. 



Fungi as food of adult Northern Corn 

Root Worm, 139. 
Fungus parasite of Corn Root Aphis, (55. 
parasites of White Grubs, 111, 112, 
116. 
cultivation and dissemination 
of, 116, 120. 
white, of Chinch Bug, X, 111, 119. 
fusca, Formica, 46, 57. 

gagates, Formica, 84, S7, 89. 
Lachnosterna, 47, 100, 102, 103, 105, 
106, 122, 123, 125. 
fusciceps, Phorbia, 7. 14. 



gagates, Formica fusca, 84, 87, 89. 
Gall insects, 49. 
Galusha, O. B., 139. 

Carman. H., 61, 64. 78, 132. 133. 134, 149. 
Gas-lime, fertilization with, for Wire- 
worms, 4 4. 
Geoica, description, 89. 

squamosa, 46, 50, 87, 93. 

chronological list showing forms, 
dates of collection, attend- 
ant ants, food plants, etc., 
87-S8. 
description, 90. 
known forms, 89. 
life history, 89. 
germanica, Setaria, 53. 
Giard, A., 112, 117. 
gibbosa, Lachnosterna, 47, 100, 102, 103, 

105, 106, 109, 121, 122, 123, 124. 
glaberrima, Lachnosterna, 122, 124. 
globuliferum. Sporotrichum, 111, 117, 119, 

120, 142. 
Glover, Townend, 19, 108. 
Goldenrod blossoms as food of adult 
Northern Corn Root Worm, 139, 142. 
gracilis, Lachnosterna, 123, 124. 
Grain Louse, 49. 

Moth, 5. 
granarius, Aphodius, 7, 12. 
grandis, Lachnosterna, 122, 125. 
Grape-vine roots, subject to attack by 

Prionus Grubs, 128. 
Grass, Blue, infested by Forda occiden- 
talis, 84. 
by Geoica squamosa, 87, 88. 
by Grass Root Louse, 76, 

77, 78. 
by Trama erigeronensis, 82. 
leaves eaten by Lachnosterna 
Beetles, 101. 
Crab-, infested by Corn Root Aphis, 
53. 
by Woolly Grass Root 
Louse. 92. 
Foxtail-, as food of Corn Root Aphis, 
53. 
destroyed by White Grubs, 99. 
Hungarian, infested bv Corn Root 

Aphis, 53. 
infested by Apple Louse, 49. 

by Geoica squamosa, 87, 88. 
by larva of Green June Beetle, 

127. 
by Prionus Grubs, 128. 
by Schizoneura corni, 79. 
by Sorghum Mealy Bug, 94. 
by Trama erigeronensis, 82. 
by White Grubs, 96, 100. 
insect, damage to lawns. X. 
June, infested bv Sorghum Mealy 

Bug, 94. 
Maggot, Black-headed, 6, 7. 14, 16. 
See under Black-headed 
Grass Maggot. 
Maggots, 4. 



Grass — Continued. 

Panic, infested by Geoica squamosa, 

88. 
Root Lice colonized upon, by Ants, 
7S. 
Louse, 46, 49, 75-82. 

characters distinguishing 
from Corn Root Aphis, 
75. 
description, 79, 
economic importance, 75, 79. 
life history, 77. 
place of hibernation, 79. 
plants infested by, 75-77. 
relations to Ants, 79. 
Woolly, 46, 92-94. 
description, 93. 
Timothy-, infested by Geoica squa- 
mosa, 87, 88. 
by Grass Root Louse, 76, 

77. 
by Sorghum Mealy Bug, 94. 
Grasshoppers, 3, 5, 139. 
Great-horned Owl as enemy of White 

Grubs, 108. 
Green June_ Beetle, 47, 127. 

description of larva, 128. 
food habits, 127. 
larva contrasted with larvse of 
Lachnosterna and Cyclo- 
cephala, 127. 
life history, 127. 
Gregarinse infesting adult Northern Corn 
Root Worm, 142. 
infesting adult Southern Corn Root 
Worm, 133. 
Ground Beetles, 65. 

Squirrels as enemies of White 
Grubs, 109. 



H 

Hackberry leaves as food of May Bee- 
tles, 101. 
Halesidota caryas and Edema albifrons 

defoliating Oak and Hickory, X. 
Hamilton, John, 21. 
Harris, T. W., 35. 
Hart, C. A., 26, 32, 79, 82, 84, 86, 89, 93, 

123 
Hart, Lydia M., 149. 

Hawk, Broad-winged, as enemy of White 
Grubs, 108. 
Red-shouldered, as enemy of White 
Grubs, 108. 
-tailed, as enemy of White 
Grubs, 108. 
Sparrow, as enemy of White Grubs, 
108, 109. 
Hazel leaves as food of May Beetles, 

101. 
Heartweed, 54. 

Helianthus blossoms as food of Northern 
Corn Root Worm, 139. 
leaves as food of Southern Corn 
Root worm, 131. 
Hemp fails to clear ground of White 

Grubs, 98, 99. 
Hermit Thrush as enemy of White 

Grubs,, 108. 
Hickory, 114. 

defoliated by Edema albifrons and 

Halesidota earyas, X. 
leaves as food of May Beetles, 101. 
hirticula, Lachnosterna, 47, 100, 101, 
102, 103, 104, 111, 121, 122, 123, 126. 
hirtiventris, Lachnosterna, 122, 123, 124. 
Hop Louse, 49. 

food plants. 49. 
Hops, injured by Wireworms, 26. 
Hormaphis, 89. 
Horn, G. H, 33, 41. 123. 



Horn-flv, report of presence in Illinois, X. 
Hucke. P. M.. 114. 
humuli, Phorodon, 49. 
Hungarian-grass infested by Corn Root 

Aphis, 53. 
hybridus, Amarantus, 53. 
Hvmenopterous parasite, 65. 

parasites of White Grubs, 109, 118. 



I 

ilicis, Laehnosterna, 100, 123, 126. 
imbricornis, Prionus, 47, 128. 
immaculata, Cycloeephala, 47, 97, 100, 

102, 107. 
implicita, Laehnosterna, 106, 123, 126. 
impressifrons, Clivina, 7, 13. 
inepta, Laehnosterna, 123, 12 7. 
infaustus, Melanotus, 7, 36, 47. 
inornata, Tiphia, 109, 110. 
Insecticides: arsenic, 43, 

arsenical poisons, 11, 43, 113, 116. 
ashes, wood. 67, 68. 
bisulphide of carbon, 44. 
coal-tar. 67. 
copperas, 43. 

and chloride of lime, 43. 
corrosive sublimate, 43. 
Fowler's solution, 43. 
gas-lime. 4 4. 
kainit, 44, 116. 
kerosene, 43, 115. 

emulsion, 43, 116. 
lime, 44, 67, 68. 

chloride of, 43, 44. 
London purple, 11. 
muriate of potash, 44. 

and petroleum, 67. 
Paris green, 11, 42, 113, 116. 

and flour, 13. 
petroleum, crude, 43. 
emulsion, 43. 
potash salts, 143. 
potassium cyanide, 43. 
salt, 43, 67, 68. 
strychnine, 43. 
sulphate of potash, 67. 

and petroleum, 67. 
superphosphates, 67. 

and petroleum, 67. 
tar. 43. 

turpentine, 43. 

and fertilizers for Corn Root Aphis, 
66-68. 
Insectivorous reptiles. 111. 
insperata. Laehnosterna, 122, 125. 
interjectus, Lasius, 46, 57, 78, 79, 82, 84. 
inversa, Laehnosterna, 47, 100, 101, 102, 

103, 104, 105, 106, 121, 122, 125. 
Ips, Banded, 7, 18, 20-24. See under 
Banded Ips. 
fasciatus, 7, 20-24, See under Banded 
Ips. 
Isaria densa infesting European White 
Grubs, 112, 117. See also under 
Botrytis tenella 
leprosa, 117, 119. 

spores of, infect White Grubs, 
119. 
italica, Setaria, 82. 



Jay, Blue, as enemy of White Grubs, 109. 

Jumping Jacks, 26. 

June Beetle, Green 47, 127. Green June 

Beetle. 
June Beetles, 96. See under White 
Grubs. 
Grass infested by Sorghum Mealy 
Bug, 94. 



Kainit, fertilization with, for White 
Grubs, 116. 
for wireworms, 44. 
Kerosene film on tubs of water at lights 
for destruction of White Grubs, 
115. 
for protecting Seed-corn against 

wireworms, 43. 
emulsion for lawns infested with 
White Grubs, 116. 
for Wireworms, 43. 
King-bird as enemy of White Grubs, 109. 
knochii, Laehnosterna, 123, 126. 
Koch, C. L., S3. 
Krassilstschik, J., 112. 



Laehnosterna afflnis, 123, 125. 

and Cycloeephala, 96-127. See under 

AVhite Grubs, 
affinis, 123, 125. 
arcuata, 122, 125. 
balia, 123, 126. 
bipartita, 122, 12 5. 
congrua, 122, 123, 124. 
corrosa, 123, 126. 
crassissima, 122. 125. 
crenulata, 102, 123, 127. 
description of larvse, 121. 
dubia, 122, 125. 
egg, 104. 

ephilida, 102, 122. 124. 
fraterna, 123, 126. 

fusca, 47, 100, 102, 103, 105, 106, 
122, 123, 125. 

date of transformation to pupa, 
106. 
to imago, 106. 

description of larva, 121. 

food of adults, 101. 

length of larval life, 100. 

time of oviposition, 105. 
gibbosa, 47. 100, 102, 103, 105, 121. 
122, 123, 124. 

date of transformation to imago, 
106. 

description of larva, 122. 

parasitized by Pelecinus poly- 
turator, 109. 

time of oviposition, 105. 
glaberrima, 122, 124. 
gracilis, 123, 124. 
grandis, 122, 125. 

hirticula, 47, 100, 102, 103, 111, 121, 
122, 123, 126. 

description of larva, 122. 

food of adult, 101. 

time of oviposition, 104. 
hirtiventris, 122, 123, 124. 
ilieis, 100, 123. 126. 
imago, life history and habits, 102- 

ratio of males to females at 
lights, 103. 
implicita, 123, 126. 

date of transformation to imago, 
106. 
inepta, 123, 127. 
insperata, 122, 125. 
inversa, 47, 100, 102, 103, 105, 122, 
125. 
date of pupal transformation, 

106. 
description of larva, 121. 
food of adult, 101. 
length of larval life, 100. 
time of oviposition, 104. 
knochii. 123. 126. 
lanceolata, 122, 124. 



Lachnosterna — Continued. 

larvae contrasted with larva of 

Green June Beetle, 127. 
larva] period, 105. 
limula, 123, 126. 
list of Illinois species, 122. 
longitarsus, 122, 124. 
marginalis, 122, 126. 
micans, 122, 125. 
nova, 123, 126. 
prseterinissa, 122. 124. 
prunina, 122, 125. 
pupation and formation of beetle, 

106. 
nibiginosa, food plant of adult, 101. 
rugosa, 47, 98, 99, 102, 121, 123, 126. 
date of pupal transformation, 

106. 
description of larva, 122. 
eggs of, 99. 

time of depositing, 105. 
tristis, 100, 102, 103, 123, 127. 
villifrons, 123. 126. 
Lamb's-quarters as food of Pale-striped 

Flea-beetle, 19. 
lanceolata. Lachnosterna, 122, 124. 
Larches infested by White Grubs, 96, 100. 
Lark. Meadow, as enemy of White 

Grubs. 108. 
Lasius attendant on Geoica squamosa, 
87, 88! 
burrows of, infested by Grass Root 

Louse, 77. 
flavus attendant on Grass Root 

Louse, 79. 
interjectus, 46, 57. 

attendant on Forda occiden- 
talis, 84. 
on Grass Root Louse, 78, 

79. 
on Trama erigeronensis, 82. 
Grass Root Louse in nest of, 78. 
mixtus, attendant on Geoica squa- 
mosa, 87, 89. 
on Trama erigeronensis, 82. 
niger, 46, 54, 57. 58, 72, 74, 79, 82, 
84, 87, 88. 
attendant on Forda occiden- 
talis, 84. 
on Geoica squamosa, 87, 88. 
on Trama erigeronensis, 82. 
and its variety alienus, 46, 54, 
57, 58, 62, 69, 72- 
75, 95. 
attendant on Corn Root 
Aphis, 54, 57, 
58, 62, 72-75. 
on Grass Root 

Louse, 79. 
on Sorghum Mealy 
Bug, 94. 
description, 74. 
differences between, 75. 
food of, 74. 
haunts, actions, and 

habits, 73. 
life history, 72. 
americanus, 72. 
laticollis. Prionus, 47, 128. 
Le Conte, J. L., 36, 37. 
leguminicola, Cecidomyia, X. 
leprosa, Isaria, 117, 119. 
Lettuce injured by Wireworms, 26. 
Lime, fertilization with, for Wireworms, 
44. 
for Corn Root Aphis, 67, 
68. 
chloride of. fertilization with, for 
Wireworms, 44. 
limula. Lachnosterna, 123, 126. 
Lintner, J. A., 15, 21, 109. 
Liquidambar leaves as food of Mav 
Beetles, 101. 



Lobelias injured by Wireworms, 26. 
lobicornis, Myrmica scabrinodis, 7, 9, 

46, 57. 
Locust, Black, leaves of, as food of May 

Beetles. 101. 
Locustkls feeding on adult Diabrotica, 

1 12. 
Locusts' eggs as food of White Grubs, 

101. 

Lombardy Poplar leaves as food of May 

Beetles, 101. 
London purple for Agonoderus pallipes, 

11. 
longicornis, Diabrotica, 30, 48, 129, 130, 

135. 
longitarsus, Lachnosterna, 122, 124. 
Ludius, 27, 
Lugger, Otto, 13 0. 
lutulentus, Aphodius, 12. 



M 

Maggot, Black-headed Grass, t>, 7, 14, 
16-18. See under Black-headed 
Grass Maggot. 
Seed-corn, 7, 14-16. See under 
Seed-corn Maggot. 
Maggots, injuries by, 7, 14-18. 
maidiradicis, Aphis, 8, 46, 50, 92. 
maidis, Aphis, 49. 
major, Plantago, 53. 
mali, Aphis, 49. 
Mally, F. W., 56, 118. 
mancus, Agriotes, 7, 26, 32, 47. 
Mangel-wurzel injured by Wireworms, 

26. 
Maple leaves as food of May Beetles, 

101. 
marginalis, Lachnosterna, 122, 126. 
Marten, John, 20, 61, 64, 67, 114, 117, 

130. 
May Beetles, 96. See under White 

Grubs. 
Mayr, G. L., 8. 
Meadow Lark as enemy of White Grub, 

108. 
Meal Moth infesting Potatoes, X. 
Mealy Bug, Corn, 46. See Sorghum 
Mealy Bug. 
Bugs, 46. 

and Plant-lice, 48-96. 
in nests of Ants, 88. 
megastachya, Eragrostis, 82. 
Melanactes, 27. 
Melanotus, 27, 39. 
americanus, 28. 

communis, 7, 28, 34, 36, 37, 38, 39, 
47. 
dates of collecting, 34, 35. 
description, 35. 
distribution, 34. 
life history, 34. 
cribulosus, 7, 18, 28, 37, 47. See 

under Corn Wireworm. 
flssilis, 7, 25, 34, 36, 41, 47. 

life history, 36. 
infaustus, 7, 36, 47. 
Melolontha vulgaris, fungous infection 

of, 117. 
melolonthse, Cordyceps, 111, 120. 
Melons as food of adult Southern Corn 

Root Worm, 131. 
Metarrhizius anisoplise, 41. 
micans. Lachnosterna, 122, 125. 
Microphthalma nigra bred from dead 

bodies of White Grubs, 110. 
Mites, 65, 111. 
mixtus, Lasius, 82, 87, 89. 
Moles as enemies of White Grubs, 109. 
molesta, Solenopsis, 8. 
Moulds as food of adult Southern Corn 
Root Worm, 131. 



Mountain Ash leaves as food of May 

Beetles, 101. 
Muriate of potash with and without 
petroleum for Corn 
Root Aphis, 67. 
fertilization with, for Wire- 
worms, 44. 
Muscardine, white. See Chinch Bug, 

white fungus. 
Muskmelon as food of Pale-striped Flea- 
beetle, 19. 
Mustard infested by Corn Root Aphis, 
53. 
to clear earth of Wireworms, 43. 
Myrmica scabrinodis lobicornis, 7, 9-10, 
46, 57. 
common in food of Birds, 

9. 
description, 10. 
distribution, 9. 
Myrmicidae, 9. 

injuries by, 7. 
Myzus achyrantes, 48. 

N 

Nematode Worms as parasites of adult 

Southern Corn Root Worm, 133. 
Nettle, Horse, as food of adult South- 
ern Corn Root Worm, 131. 
niger alienus, Lasius, 46, 54, 57, 58, 62, 
69, 72, 79, 94, 95. 
americanus, Lasius, 72. 
Lasius, 46, 54, 57, 58, 72, 74, 79, 82, 
84, 87, 88. 
nigra, Brassica, 53. 

Microphthalma, 110. 
nitida, Allorhina, 47, 127. 
Northern Corn Root Worm, 48, 129, 
130. 135-145. 
characters distinguishing from 
Wireworms and larvae of 
small Flies, 136. 
dates at which beetle has been 

collected, 141. 
description, 143-145. 
distinguishing characters of 

larva, 144. 
distribution, 138. 
food of beetle, 137, 138, 140. 
habits, 140. 
life history, 139. 
injuries, 136. 

indications of, 137. 
period of, 137. 
most noticeable, 137. 
natural enemies, 142. 
prevention and remedy, 142. 
nova, Lachnosterna, 123, 126. 



Oak defoliated by Edema albifrons and 
Halesidota caryse, X. 
leaves as food of May Beetles, 101, 
102, 105. 
Oats, 77, 99, 107. 

as food of adult Southern Corn 
Root Worm, 131. 
of Corn Root Aphis, 53, 66. 
attacked by Wireworms, 26. 
damage to, by Chinch Bug, VIII. 
infested by Geoica squamosa, 87, 
88. 
occidentalis, Forda, 46, 50, 84 
Oestlund, O. W., 83. 
oleracea, Partulaca. 53. 
Onions injured by Wireworms, 26. 
Ophion. 110. 

bifoveolatum as parasite of White 
Grubs, 110. 
Osborn, Herbert, 75, 118. 



Owl, Barred, as enemy of White Grubs, 
108. 
Great-horned, as enemy of White 

Grubs, 108. 
Screech, as enemy of White Grubs, 
108. 
Oxalis stricta infested by Corn Root 
Aphis, 53. 



Packard, A. S., 21. 
Pale-striped Flea-beetle, 7, 18-20. 
description, 19. 
food of, 19. 
pallipes, Agonoderus, 7, 11. 
Panic-grass infested by Geoica squa- 
mosa, 88. 
panici, Rhizobius, 94. 

Tychea, 94. 
panicola, Schizoneura, 46, 50, 59, 75. 
Panicum crus-galli infested by Geoica 
squamosa, 88. 
glabrum infested by Grass Root 
Louse, 75. 
by Schizoneura venusta, 82. 
infested by Corn Root Aphis, 53. 

by Grass Root Louse, 78. 
proliferum infested by Woolly Grass 
Root Louse, 92. 
Parasites, hymenopterous, 65, 118. 
Parasitic Bacteria, 132, 133. 
Diptera, 110, 133. 

Fungi, IX, 41, 65, 105, 108, 111, 112. 

destructive to White Grubs, 116, 

117, 120. 

Insects as enemies of White Grubs, 

109. 

Paris green for Agonoderus pallipes, 11. 

and flour for Aphodius gra- 

narius, 13. 
for June Beetles, 113, 116. 
for Wireworms, 42. 
Passerini, J., 82. 

Peach pits destroyed by Wireworms, 26. 
Pear leaves as food of May Beetles, 101. 
Pears injured by adult Banded Ips, 21. 
Peck, C. H., 21, 22 
Pelecinus polyturator as parasite of 

White Grubs, 109, 118. 
Pemphigina?, 89, 93. 
Pennsylvania, Disonycha, X. 
Pergande, H, 75. 
Pergande, Theodore, 9, 
Perkins, G. H., 101, 116. 
Petroleum and muriate of potash for 
Corn Root Aphis, 67. 
and sulphate of potash for Corn ' 

Root Aphis, 67. 
and superphosphates for Corn Root 

Aphis, 67. 
crude, for Wireworms. 43. 

emulsion for Wireworms, 43. 
Pettit, J., 33, 
Phallus as food of adult Northern Corn 

Root Worm, 139. 
phaseoli, Tychea, 87, 89. 
Phorbia fusciceps, 7, 14-16. See under 

Seed-corn Maggot. 
Phorodon humuli, 49. 

food plants, 49. 
Pigeon-grass, 28. 70. 

as food of Corn Root Aphis, 53, 54, 
59, 66. 
Pigs as enemies of White Grubs, 109, 

112, 116. 
Pigweed. 28. 

as food of Pale-striped Flea-beetle, 

19. 
infested by Corn Root Aphis, 53. 
Pinks injured by Wireworms, 26. 



IX 



Plantago major infested by Corn Root 

Aphis, 53. „, 

Plantain as food of Pale-striped Flea- 
beetle, 19. 
infested by Corn Root Aphis, 53. 
Plant-lice, 15. 

and Mealy Bugs, 48-95. 

points distinguishing, 48. 
Ants associated with, 50. 
differences in life history, 49. 
fungus disease of, 65. 
number of species infesting corn 

roots in Illinois, 50. 
key to species infesting corn roots, 

50. 
rate of multiplication, 48, 56. 
(See under Corn Leaf Aphis and 
Corn Root Aphis.) 
Plowing, late fall, as measure against 
Corn Root Aphis, 70. 
against Wireworms, 31, 42. 
to destroy Ants In attend- 
ance on Corn Root 
Aphis, 69. 
Plum as food of Hop Plant Louse, 49. 
leaves as food of adult Southern 
Corn Root Worm, 131. 
of May Beetles, 101. 
pose, Rhizobius, 94. 

Poisons, arsenical, effect on Seed-corn, 
43. 
for Agonoderus pallipes, 11. 
for Wireworms, 42, 43. 
(See also under Insecticides.) 
Pollen. 131, 137, 138, 139, 141. 
Polygonum as food of Corn Root Aphis, 
53. 
infested by Grass Root Louse, 77. 
Polvmoechus brevipes dusted with spores 

of Botrytis tenelia, 117. 
polyturator, Pelecinus. 109, 118. 
Poplar, Lombardy, leaves of, as food of 

May Beetles, 101. 
Portulaca destroyed by White Grubs, 99. 
oleracea as food of Corn Root Aphis, 
53. 
Potash salts for Northern Corn Root 

Worm, 143. 
Potassium cyanide for Wireworms, 43. 
Potatoes as food of Pale-striped Flea- 
beetle, 19. 
infested by Wheat Wlreworm, 32. 
by White Grubs, 96, 100. 
by Wireworms, 26. 
prsetermissa, Lachnosterna, 122, 124. 
Predaceous Insects, 110, 111, 133, 142. 
Prionus Grubs, 128. 

economic significance, 128. 
imbricornis. 47, 128. 
laticollis. 47, 12S. 
proliferum, Panicum, 92. 
prunina. Lachnosterna, 122, 125. 
pubescens, Agriotes, 7, 34, 47. 
pulicaria, Chsetocnema. VII. 
Pumpkins as food of adult Northern 
Corn Root Worm, 139. 
of adult Southern Corn Root 
Worm, 131. 
Purslane. 28, 53. 65. 

as breeding plant o" Corn Root 

Aphis. 53, 56-57. 
as food of Pale-striped Flea-beetle, 

19. 
destroyed by White Grubs, 99. 
infested by Solenopsis debilis, 9. 
by an unidentified larva, 138. 
Pyralis farinalls infesting potatoes, X. 



Raccoon as enemy of White Grubs, 109. 
radicola. Tychea, SIT. 



Ragweed, 137. 

as food of Corn Root Aphis, 53. 
of Pale-striped Flea-beetle, 19. 
of Southern Corn Root Worm, 
131. 
blossoms and pollen as food of adult 
Northern Corn Root Worm, 
137, 142. 
Rape injured by Wireworms, 26. 

fails to clear earth of Wireworms, 
43. 
Raspberries* injured by adult Banded 
Ips, 21. 
leaves eaten by adult Southern Corn 
Root Worm, 131. 
by May Beetles, 101. 
Red Clover blossoms as food of adult 
Northern Corn Root Worm, 13 9. 
-shouldered Hawk as enemy of 

White Grubs, 108. 
-tailed Hawk as enemy of White 
Grubs, 108. 
Remedies and preventives for insect dep- 
redations : arsenic, 43. 
arsenical poisons, 11, 43, 113, 

116. 
ashes, wood, 67, 68. 
bisulphide of carbon, 44. 
clean fallow, 43. 
coal-tar, 67. 
collection and destruction, 112, 

113-115. 
copperas, 43. 

and chloride of lime, 43. 
corrosive sublimate, 43. 
cultivation of buckwheat, 43. 
of mustard, 43. 
of rape, 43. 
destruction of Ants* nests, 66, 

fertilizers, 65, 113. 

and insecticides, 66-67. 
food lures, 42. 
Fowler's solution, 43. 
gas-lime, 44. 

infection material, IX, 117-120. 
jarring trees, 113, 114-115. 
kainit, 44, 116. 
kerosene, 43, 115. 

emulsion, 43, 116. 
late fall plowing. 31, 42, 69, 70. 

planting of corn, 42, 66. 
light-traps, 113, 115. 
lime, 44, 67, 68. 

chloride of, 44. 
London purple, 11. 
muriate of potash, 44. 

and petroleum, 67, 
Paris green, 11, 42. 
and flour, 13. 
pasturing of pigs, 112, 113. 
petroleum, crude. 43. 

and fertilizers, 67. 
emulsion, 43. 
potash salts, 143. 
potassium cyanide, 43. 
rotation of crops, 42, 44, 51, 66, 

70. 96, 113, 134, 142. 
salt, 43. 67, 68. 
spraying, 113, 116. 
starvation. 69. 
strychnine, 43. 
sulphate of potash, 67, 116. 

and petroleum, 67. 
superphosphates. 67. 

and petroleum, 67.* 
tar, 43. 
turpentine, 43. 
Reptiles and Amphibians as enemies of 

White Grubs, 111. 
Rhizobiinai, 89, 93. 



Rhizobius, 89, 93. 
panici, 94. 
pose, 94. 

spicatus, 46, 50, 92-94. 
description, 93. 
Riley. C. V., 11, 14, 15, 21, 101, 108, 109, 

110, 111, 118, 127, 132, 134, 149. 
Robin as enemy of Wireworms, 41. 

of White Grubs, 108, 109. 
Root Aphis, Corn, 48, 50-75. See under 
Corn Root Aphis, 
blight of Corn, 4, 45, 52. 
-lice, Corn, 3, 45, 46, 48, 50. See 

under Plant-lice. 
Louse, Corn, 3, 4, 45, 50-75. See 
under Corn Root Aphis. 
Grass, 46, 49, 75-82. 
Woolly Grass, 46, 92-94. 
description, 93. 
Web-worms, Corn, 5. 
Worm, Northern Corn, 30, 48, 129, 
13 5-145. See under North- 
ern Corn Root Worm. 
Southern Corn, 47, 129-135. See 
under Southern Corn Root 
Worm. 
Worms, Corn. 3, 5, 45. 
rosse, Siphonophora, 48. 
Roses, petals of, as food of adult South- 
ern Corn Root Worm, 131. 
Rotation of crops for Corn Root Aphis, 
51, 66, 70. 
for Cutworms, 44. 
for Northern Corn Root Worm, 

142. 
for Southern Corn Root Worm, 

134. 
for White Grubs, 44, 96, 112, 

113. 
for Wireworms, 42. 44. 
rubiginosa, Lachnosterna, 101. 
Rudbeckia roots, pupa? of Southern Corn 

Root Worm found among-, 130. 
rufans, Bacillus, 132. 
rugosa, Lachnosterna, 47, 98, 99, 102, 

105, 106, 121, 122, 123, 126. 
Rumex crispus infested by Corn Root 

Aphis, 53, 65. 
Rye as breeding plant of Chinch Bug. 
VIII. 
subject to injury by Wireworms, 26. 



Salt for Corn Root Aphis, 67, 68. 

for Wireworms, 43. 
scabrinodis lobicornis, Myrmiea, 7, 9, 46, 

57. 
schaufussi. Formica, 46, 57, 79. 
Schizoneura corni. 49, 75, 79. 

plants infested by 49. 79. 
panicola, 46, 50, 59, 75-S2. See un- 
der Grass Root Louse, 
venusta, 82. 

plants on which it occurs, 82. 
Sciara sp., 7, 16-18. See under Black- 
headed Grass Maggot. 
Scirpus fluviatilis infested by Southern 

Corn Root Worm, 130. 
Screech Owl as enemy of White Grubs, 

10S. 
Sedges infested by Southern Corn Root 

Worm, 130. 
Seed-corn Maggot, 7, 14-16. 
^description, 15. 
distribution, 14. 
life history, 15. 
Maggots, 4, 6. 
Serica vespertina dusted with spores of 
Botrytis tenella, 117. 



Setaria as food of Corn Root Aphis. 53. 
54. 
destroyed by White Grubs, 99. 
germanica infested by Corn Root 

Aphis, 53. 
glauca infested by Schizoneura ve- 
nusta, 82. 
infested by Grass Root Louse, 77, 

78. 
italica, infested by Schizoneura 

venusta, 82. 
viridis infested by same, 82. 
setariae, Tychea, 89. 
Shepherd's Purse infested by Geoica 

squamoija, 87, SS. 
Siphonophora avense, 49. 

rosae, 48. 
Six-legged larva?, injuries by, 7, 1S-44. 

47, 
Skunks as enemies of White Grubs, 109. 
Slingerland, M. V., 48. See Comstock, J. 

H., and Slingerland. 
Small-striped Squash Beetle, 137. 
Smartweed, 54, 60, 70, 137. 

as food of Corn Root Aphis, 53, 54, 

66, 68. 
infested by Grass Root Louse, 76, 

78. 
pollen as food of adult Northern 
Corn Root Worm, 139. 
Smith, J. B., 37, 124. 
Solanum carolinense as food of Southern 

Corn Root Worm, 131. 
Solenopsis debilis, 7, 8, 46, 57. 

attendant on Corn Root Aphis, 8. 
on Geoica squamosa, 88, 89. 
description, 9. 
distribution, 8. 
iniuries to strawberries, 8. 
fugax, 8. 
molesta, 8. 
sorghiellus. Coccus. 94. 
Dactylopius, 46, 94. 
Sorghum, 62, 63, 142. 

favorable to development of North- 
ern Corn Root Worm, 138. 
infested by Corn Leaf Aphis, 60, 61. 
by Corn Root Aphis, 52, 60. 
by Grass Root Louse, 77. 
by Sorghum Mealy Bug, 94. 
Louse, Yellow, 61, 63. 
Mealy Bug, 46. 94-95. 

as a Grass Insect, 94. 
Ants attendant on, 94, 95. 
dates of collection, 94, 95. 
description, 95. 
methods of multiplication. 

94. 
plants infested by, 94. 
pollen as food of adult Northern 
Corn Root Worm, 139. 
Sorrel infested by Corn Root Aphis. 53. 
Southern Corn Root Worm, 47, 129-135. 
138. 
character of injury, 129-131. 
description. 134-135. 
food of adult. 130-131, 133. 
injury to Sweet Corn, 130, 134. 
life history, 131. 
natural enemies, 132. 
remedial measures, 134. 
Sparrow, English, as enemy of White 
Grubs, 10S-109. 
Hawk as enemv of White Grubs, 
108, 109. 
spicatus. Rhizobius, 46, 50. 92. 
Sporotrichum, 105. 

globuliferum. HI. 117. 120. 142. 

spores of, infect White Grubs. 
119. 
Spraying trees for destruction of May 
Beetles, 113. 116. 



squamosa, Geoica, 46, 50, 87, 93. 
Squash as food of adult Southern Corn 
Root Worm, 131, 134. 
infested by Corn Root Aphis, 53. 
pollen as food of adult Northern 

Corn Root Worm, 139. 
-vines infested by adult Northern 
Corn Root Worm, 139. 
Squirrels. Ground, as enemies of White 

Grubs, 109. 
Stalk-borer. 5. 

Strawberries infested by White Grubs, 
96, 100. 
injured by Solenopsis debilis, 8. 
by Wireworms, 26. 
Strawberry fields infested by larva of 
Green June Beetle, 127. 
leaves as food of Pale-striped Flea- 
beetle, 19. 
stricta, Oxalis, 53. 
Strigosus, Cyperus, 130. 
strumarium, Xanthium, 94. 
Strychnine for Wireworms, 43. 
Sulphate of potash for Corn Root Aphis, 
67. 
and petroleum for same, 67: 
Sunflowers as food of adult Southern 
Corn Root Worms, 131. See Heli- 
anthus. 
Superphosphates for Corn Root Aphis, 
67. 
and petroleum for Corn Root Aphis, 
67. 
Sweet Corn injured by Banded Ips, 21. 
by Southern Corn Root Worm, 
130, 134. 
Gum Leaves as food of May Beetles, 
101. 
Systena tseniata, 7. 18-20. See under 
Pale-striped Flea-beetle, 
var. blanda, 20. 



Tachinid parasite of adult Southern 
Corn Root Worm, 133. 
of White Grubs, 110. 
tseniata blanda, Systena, 20. 

Systena, 7, IS. 
Tar for protection against Wireworms, 

43. 
Tea, New Jersey, as food of adult Laeh- 

nosterna rubiginosa, 101. 
tenella, Botrytis, 112, 117, 118, 119. 
Terrill, J. S., 64, 67. 
Thaxter, Roland. 41. 65, 119. 
Thistle blossoms as food of adult North- 
ern Corn Root Worm, 13 9, 141. 
Thomas, Cyrus, 21. 75, 82. 
Thrush, Alice, as enemy of Wireworms, 
41. 
Brown, as enemy of White Grubs, 
108, 109. 
of Wireworms, 41. 
Hermit, as enemy of White Grubs, 
108. 
of Wireworms, 41. 
Wood, as enemy of White Grubs, 
108. 
of Wireworms, 41. 
Timothv bulbs burrowed by Wireworms, 
26. 
infested by Geoica squamosa, 87, 
88. 
by Grass Root Louse. 76, 77. 
by Sorghum Mealy Bug, 94. 
Tiphia inornata as enemy of White 
Grubs, 109-110. 
description, 110. 
Toads as enemies of May Beetles, 111. 



tomentosus, Chlaenius, 111. 
Townsend, C. H. T., 127. 
Trama, 83. 

erigeronensis, 46, 50, 82. 
description, 82. 

plants taken upon, with dates 
and situation, 82. 
Traps, light-, for May Beetles, 113, 115. 
Treat, Mary. 111. 
tristis. Lachnosterna, 100, 102, 103, 123, 

127. 
Turkeys as enemies of White Grubs, 109. 
Turnips infested by Wireworms, 26. 
Turpentine as protection against Wire- 
worms, 43. 
Tychea, 83, 89. 

brevicornis, 46, 50, 86, 89. 

description, 86. 
panici, 89, 94. 
phaseoli, 87, 89. 
radicola, S3, 
setariae, S9. 



venusta, Schizoneura, 82. 

Ver blanc, 97. See under White Grubs. 

vespertina, Serica, 117. 

villifrons, Lachnosterna, 123, 126. 

viridis, Setaria, 82. 

Voorhees, E. B., 44. 

vulgaris, Melolontha, 117. 



W 



Walles, A., 114. 

Walnut, Black, leaves of, as food of 

May Beetles, 101. 
Walsh, B. D., 14, 21, 60, 100. 
Warren, B. H., 109. 

Weasels as enemies of White Grubs, 109. 
Webster, F. M., 8, 13, 15, 30, 32, 130, 

131, 132, 136, 139. 
Weed, C. M., 53, 61, 78. 
Weevils, 3, 5. 
Westergren, M., 149. 
Wheat, 53, 66, 77. 

as food of larva of Green June 
Beetle, 127. 
of Wireworms, 25, 26. 
Corn Leaf Aphis breeding on, 64. 
infested by Schizoneura venusta, 82. 
by Drasterius elegans, 29. 
by Wheat Wireworm, 32. 
kernels .as food of adult Southern 

Corn Root Worm, 131. 
liable to injury by White Grubs, 

100. 
Spring, as breeding place of Chinch 

Bug, VIII. 
stalk being eaten by Southern Corn 

Root Worm, 130. 
Wireworm, 7, 32-34, 47. 
description, 33. 
notes on life history, 33. 
relative abundance, 32. 
White Ants, injuries at State House, X. 
fungus of Chinch Bug, IX, 111-112, 

119. 
grub of Green June Beetle con- 
trasted with larvae of Lachno- 
sterna and Cvclocephala, 127. 
Grubs, 3, 4, 44. 45, 46, 47, 51, 96-127. 
contagious diseases of, 112-120. 
description of, 117-122. 
eggs of, 96, 97, 104, 105. 
European, diseases of, 112. 

standard method against, 
114. 



XII 



White Grubs — Continued. 

food of imagos, 101-102. 
preference of 
species, 101. 
of larvae, 96, 100-101. 
fluctuation of numbers, 96. 
injuries, 97-102. 

life history and habits, 102-107. 
locust eggs as food of, 101. 
natural enemies, 107-112. 
number of Lachnosterna species 

of, in Illinois, 97. 
preventive and remedial meas- 
ures against, 112- 
117. 
general, 113. 
local, 112. 
species injurious to Corn in Illi- 
nois, 100. 
Wilcox, E. V., 42, 108. 
Willow leaves as food of May Beetles, 

101. 
Wireworm, Corn, 7, 18, 37-39, 47. See 
under Corn Wireworm. 
Wheat, 7, 32-34, 47. See under 
Wheat Wireworm. 



Wireworms, 3, 4, 6, 7, 18, 24-44, 45, 47, 
51, 129, 144. 

generic synopsis, 27. 

natural enemies, 41. 

prevention and remedy, 42. 
Woodpecker as enemy of White Grubs, 

108. 
Wood Thrush as enemy of White Grubs, 

108. 
Woodworth, C. W., 142. 
Woolly Grass Root Louse, 46, 92-94. 
description, 93. 



Xanthium strumarium infested by Sor- 
ghum Mealy Bug, 94. 



Yellow Sorghum Louse, 61, 



zeas, Anthomyia, 14.