REPORT OF THE STATE ENTOMOLOGIST I907 369 



MAYETIOLA Kieff. 



This genus is of particular interest, as it includes the exceedingly 

 injurious wheat pest known as the Hessian fly, M. destructor 

 Say. It comprises an assemblage of species which may be recog- 

 nized by the third vein uniting with costa at or beyond the apex, in 

 connection with the quadriarticulate palpi and simple claws. Plate 

 36, figure 6 illustrates a unique form, possibly the representative of 

 another genus. 



Key to species 

 « 12 to 15 antennal segments 

 b 12 antennal segments 



c Abdomen yellowish ; antennae light brown, the segments sub- 

 sessile; male (O 1 i go t r op h u s) azaleae Felt, C. 48 



bb 13 sessile or subsessile antennal segments 



c Abdomen and antennae dark brown ; male 



(Oligotrophus) ace r is Felt, C. 66a 

 cc Abdomen reddish brown; ovipositor ^4 the length of the body; 



female v i r g i n i a ri a n. sp., C. 80 



ccc Abdomen reddish brown ; ovipositor as long as the body ; female 



b a 1 s a m i f e r a n. sp., C. 146 

 bbb 14 antennal segments 



c Posterior tarsi normal 



. d Antennal segments sessile 



e Abdomen reddish brown, the Sth antennal segment with 

 a length twice its diameter, the 4th palpal segment H 

 longer than the 3d ; ovipositor 1/5 the length of the 



abdomen electra n. sp., C. 507 



ce Abdomen bright red, the Sth antennal segment with a 

 length 2l4 times its diameter, the 4th palpal segment 

 a little longer than the 3d; ovipositor as long as the 



body, female; bred from elm buds and folded leaves 



ulmi Beutm., C. 1239, ai683 

 dd Antennal segments subsessile, with a stem J4 or J/^ the 

 length of the basal enlargement 

 e 3d vein uniting with costa well beyond the apex 



/ Abdomen pale yellowish, the 5th antennal segment ' 

 with a stem ^ the length of the basal enlargement; 



male 



(Oligotrophus) f h a 1 i c t r i Felt, C. 98 

 ee 3d vein uniting with costa just beyond the apex 



/ Abdomen brownish red; ovipositor short; female 



s o c i a 1 i s n. sp., C. 97 



ff Abdomen yellowish or fuscous yellowish; ventral 



plate of the male deeply and roundly emarginate 



distally; the female with the ovipositor as long as 



the body ; bred from rolled violet leaves 



(Diplosis) violicola Coq., C. ai346 



