86 ILLINOIS BIOLOGICAL MONOGRAPHS [404 



10(17) Body without numerous small tuberculate areas, usually without fine longitudinal 

 series of sub-adjacent patches; thorax, at least, always suffused on dorsum with 

 darker shade 11. 



11(12) Body shiny metallic fuscous; dorsum of all segments grayish brown; tenth abdominal 

 tergum uniformly black; Y-132-2-1 (on Carpinus caroliniana) , Y-132m-l-2 (on 

 Mows alba), Y-193 (on Alnus rugosa), erythrogastra Norton. 



12(11) Body not shiny metallic fuscous; dorsum of none of segments grayish-brown; tenth 

 abdominal tergum not uniformly black 13. 



13(14) Abdomen on dorso-meson with a fine longitudinal line; tenth abdominal tergum 

 fuscous on dorso-meson; suranal processes distinctly fuscous; on Alnus; M-114. 



Pteronidea sp. 2. 



14(13) Abdomen on dorso-meson without a fine longitudinal line; tenth abdominal tergum 

 not fuscous on dorso-meson; suranal processes not distinctly fuscous 15. 



15(16) Tenth abdominal tergum with a fuscous triangular mark on each side of meson; head 

 more or less uniformly brown; on Salix rostraia; Y-169, C-427-45. .Pteronidea sp. 3. 



16(15) Tenth abdominal tergum without a fuscous triangular mark on each side of meson; 

 head not uniformly brown but epicranial stem, vertex dorsad of ocellarae, front in the 

 center, and labrum distinctly darker; on hazel (?); M-153 Pteronidea sp. 4. 



1 7(10) Body with numerous small blackish tuberculate areas; sometimes with fine interrupted 

 longitudinal lines composed of irregular subadjacent colored areas; thorax on dorsum 

 never suffused with darker shade 18. 



18(27) Body on dorso-meson with a fine more or less continuous black line independent of 

 greenish or pale dorsal vessel, line occasionally faint but never entirely obsolete; 

 latus usually with fine more or less continuous longitudinal lines 19. 



19(20) Abdomen on ventro-meson with fuscous spots; larvapods on cephalic surpedal 

 areas never with fuscous spots; on Alnus; M-232 Pteronidea sp. 5. 



20(19) Abdomen on ventro-meson never with fuscous spots; larvapods on cephalic surpedal 

 areas often with fuscous spots 21. 



21(24) Antennae with antacoriae distinct, not limited to periphery of an ta fossae; antennal 

 segment 1 very minute, never more than twice as long as wide; segment 2 usually 

 incomplete, if complete, ventral portion never more than a mere faint line; segment 3 

 usually complete, cephalic portion reduced to a line 22. 



22(23) Larvapods on cephalic aspect with minute irregular blackish or brownish spots near 

 setae; on Salix; Y-8.48(?)-l Pteronidea sp. 6. 



23(22) Larvapods on cephalic aspect without minute irregular black spots near setae; on 

 Salix spp.; Y-6-1,-6-6,-44-1-1, M-156 (in part), C-140, C-649 odoratus Dyar. 



24(21) Antennae with antacoriae indistinct, limited to periphery of antafossae; antennal 

 segment 1 complete, or if incomplete, never less than twice as long as wide; segments 

 2 and 3 always complete, their cephalic and dorsal portions never reduced to mere 

 lines; segment 4 cylindro-conical; all four segments often fused together in part and 

 filling antafossae almost completely; larvapods on cephalic aspect with irregular 

 black spots near setae, spots sometimes very minute but never wanting from all 

 larvapods 25. 



25(26) Antennae with all 4 segments fused together in part and filling antafossae almost 

 completely; on Salix spp.; Y-95-1-1, Y-8.45 (?)s-l-l corneUi Marlatt. 



26(25) Antennae without all 4 segments fused together in part; segment 1 always dis- 

 tinctly separated from the other segments; antacorriae always distinct; on Populus; 

 M-156 (in part) Pteronidea sp. 7 



27(18) Body on dorso-meson never with a fine more or less continuous black line independent 

 of greenish or pale dorsal vessel; latus usually without fine more or less continuous 

 longitudinal lines 28. 



