Vol. XXX] ENTOMOLOGICAL N'F.WS 9 



bristles present; basal joint of hind tarsus slightly over one-half as 

 long as second, the latter about as long as joints 3 to 5 combined, the 

 entire tarsus slightly longer than the tibia. Veins 3 and 4 convergent 

 apically; outer cross-vein at about 1.5 its own length from apex of filtii 

 vein. 



9. Similar to the male in chaetotaxy; genitalia very slender. 

 Length, 2.5 to 3 mm. 



Type and allotype, White Heath, Illinois. April 19, 1918; 

 larvae under bark of fallen cottonwood tree ; imagines emerged 

 April 26, 1918. 



Closely resembles maurus Wheeler, but has black tegular 

 cilia and differs in other respects. 



The larva makes a cocoon similar to that of Drapctis but 

 not so tough. The pupa is white, distinctly shining, with th/ 

 cephalic thorns dark brown. The following notes indicate 

 distinctions between this species and Argyra albicans Loew 

 as described by Marchand. 



The thoracic respiratory organs are more slender, the ce- 

 phalic thorns are closely contiguous, with 2 long hairs at their 

 bases above and 2 slight elevations ventrad of them, on each 

 of which there is a long hair. The two protuberances re- 

 ferred to as converging bristles above the mouth-parts by 

 Marchand are the apices of what I take to be the aristae, 

 which are straight in Medctcrus, the remainder of the an- 

 tennae being clearly traceable to the bases of the cephalic 

 tubercles. The wing-pads are longer in Mcdcterus than shown 

 by Marchand, extending to base of third segment of abdo- 

 men ; the position of the legs is similar in both species. The 

 abdomen differs from that of albicans in having a series of 

 long, sharply pointed, dense, appressed bristles on apices of 

 segments i to 8 inclusive. In other respects the specit -. 

 similar, except that cacrulescens is only 3 mm. in length. 



Imagines of Medeterus are nearly always found on tin- 

 trunks of trees or on exposed vertical surfaces close to in 

 while those of Argyra are found either on low vegi or 



on bare sand close to streams. Both genera are common to 

 Europe and North America. 



