REPORT OF THE STATE ENTOMOLOGIST I907 369 



MAYETIOLA Kicff. 



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 

 a 12 to 15 antennal segments 

 b 12 antennal segments 



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

 sessile; male (O 1 i g o t r o p h u s) azaleae Felt, C. 48 



hh 13 sessile or subsessile antennal segments 



c Abdomen and antennae dark brown; male 



(Oligotrophus) aceris Felt, C. 66a 

 cc Abdomen reddish brown; ovipositor J4 the length of the body; 



female virginiana n. sp., C. 80 



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



balsamifera n. sp., C. 146 

 hbh 14 antennal segments 



c Posterior tarsi normal 



d Antennal segments sessile 



e Abdomen reddish brown, the 5th antennal segment with 

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

 longer than the 3d; ovipositor l/s the length of the 



abdomen electra n. sp., C. 507 



ee Abdomen bright red, the 5th antennal segment with a 

 length 2y2 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 



u 1 m i Beutm., C. 1239, a 1683 

 dd Antennal segments subsessile, with a stem Y^. or Yz the 

 length of the basal enlargement 

 e 3d vein uniting with costa well beyond the apex 



f Abdomen pale yellowish, the 5th antennal segment 

 with a stem Ya the length of the basal enlargement; 



male -> 



(Oligotrophus) t'halictri Felt, C. 98 

 y 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 



