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-11 7-1-1, 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 Irichocarpa; 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 Pkris 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 purphsh 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, clj^ieus, 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. .similis Norton. 



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

 furrows; tj^jically pale on vertex ventrad of vertical furrows and caudad of ocellarae; 

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



