56 ILLINOIS BIOLOGICAL MONOGRAPHS [374 



larvae of this genus are easily obtained and readily identified because of 

 the marked asymmetry of the labrum. 



The following key will serve to separate the species studied: 



SPECIES OF DOLERUS 



1(6) Head uniformly pale, creamy, or pale brown; body uniformly whitish or greenish, 

 without distinct dorsal band 2. 



2(3) Body with small black spots on each segment along supraspiracular and pedal lines; 

 head pale brownish yellow; spots on ninth abdominal segment much smaller than 

 preceding ones; length, 25 mm.; on wheat and grasses; Y-l 17-1-1, G-d-1. Dolerus sp. 1. 



3(2) Body without small black spots on each segment along supraspiracular and pedal 

 lines; head creamy; length less than 25 mm 4. 



4(5) Distance between antennaria and mandibularia subequal to distance between anten- 

 naria and ocularium; length, 20 mm.; on Carex trichocarpa; Y-24-5-2, -145-1(?),-147. 



Dolerus sp. 2. 



5(4) Distance between antennaria and mandibularia twice or more than twice the distance 

 between antennaria and ocularium; length of prothoracic spiracles in relation to 

 vertical diameter of antennaria variable; femur with or without disto-ventral pro- 

 jection; front with or without pale brown spot; length 18-20 mm.; on grasses, sedge, 

 timothy; Y-29- 11,-32-1, M-7, H,-41-l,-63,-225 Dolerus sp. 3" 



6(1) Head spotted, banded, or distinctly brown, black, or purple; body uniformly longi- 

 tudinally banded or striped on dorsum, especially along dorso-lateral lines, rarely 

 uniformly whitish or greenish 7. 



7(8) Head with a distinct blackish semicircular band extending from gena to gena dorsad 

 of front and involving ocellarae; body with a very fine brownish line along latero- 

 dorsal lines, more distinct on caudal segments; thoracic legs uniformly pale; length, 

 15 mm.; on grasses; Y-41-l-l,-41-2,-41-3,-8.47(?) M-41,-235 Dolerus sp. 4. 



8(7) Head without distinct blackish semicircular band, but with spots or dark-colored 

 areas; thoracic legs with femur, tibia, and claws brown, not concolorous with coxa. .9. 



9(12) Head pale brown, vertex with brown spots; body uniformly whitish or with light 



dorsal band .. 10. 



10(11) Vertex with two small spots, one dorso-mesad of each vertical furrow, variable in 

 size but never linear along the furrow; body uniformly whitish or creamy; length. 



21 mm.; on Carpinus and Pteris aquilina (both doubtful); Y-74-1-1, M-82 



Dolerus sp. 5. 



11(10) Vertex with one minute spot at the origin of epicranial stem; light brown spot along 



epicranial suture to ocellarae; body with dorsal band lighter on dorso-meson and 



darker on supraspiracular lines, more distinct on caudal segments; length, 15 mm.; 



on Equisetum arvense; Y-145-2 Dolerus sp. 6. 



12(9) Head brownish with purplish or brownish markings on vertex, only rarely light 

 brown or yellowish, then vertical furrows with brownish streaks; body with distinct 



dorsal band 13. 



13(14) Head deep purplish black with following parts whitish: proximal half of epicranial 

 stem, vertical furrows, vertex caudad of ocellarae to the middle of epicranial stem 

 very narrowly, epicranial arms, clypeus, and labrum; dorsal band lighter on dorso- 

 meson; pedal lines with a row of grayish patches; legs with femora without disto- 

 ventral projection; length, 19 mm. ; on Equisetum arvense; Y- 146-1-2 . . si mil is Norton. 

 14(13) Head usually brownish or yellowish, vertex deeply brown, at least along vertical 

 furrows; typically pale on vertex ventrad of vertical furrows and caudad of ocellarae; 

 front with or without brownish spot; tenth abdominal tergum on both sides usually 



