136 INSECUTOR INSCITI^ MENSTRUUS 



the Chilosia, and has worked out the life history of some of 

 the species causing black check in the western hemlock. He 

 bred Chilosia hoodiana from Abies concolor and grandis; and 

 C. burkei from Tsiiga heterophylla. This latter species was 

 determined as Cheilosia olaskensis Hunter by Coquillett. 



Until a few years ago the hairy eyed species of Chilosia were 

 considered to be almost entirely of western distribution in 

 North America. About half a dozen species are now known 

 to occur in the eastern United States. 



In this study the writer has separated the Chilosia (old sense) 

 somewhat after the manner of Becker, according to the pilosity 

 of the eyes and face. 



He has supplemented the character of "eyes hairy" with 

 the character "antennal pits separated," and has considered 

 the species having these characteristics as forming the genus 

 Chilosia and for those with "eyes bare" and "antennal pits" 

 confluent he has resurrected Bigot's generic name Cartosyrphus. 

 This makes nearly an even division of our North American 

 species. 



Unfortunately the type species of Chilosia, flavipes, has the 

 eyes sometimes bare in the female but the writer believes that 

 this species will be found to have the antennal pits separated, 

 which would put the genus Chilosia on a better basis. 



Each of these genera may be further divided into two sub- 

 genera. The Chilosia with hairy face are considered as form- 

 ing the subgenus Chilomyia; those with bare face form the 

 subgenus Chilosia. Cartosyrphus is divided by arista long 

 plumose, subgenus Hiatomyia, and arista short plumose, sub- 

 genus Cartosyrphus. There are other smaller groups of species 

 containing closely allied forms, which are distinct from the 

 other species, such as the comosa group which have the frons 

 and face very broad, the arista very short and thorax without 

 bristles, but it would avail nothing to consider such groups 

 as subgenera. 



The pile on the face apparently makes an arbitrary division 

 in Chilosia, as among the hairy faced forms there are some 

 which are closelv related to the bare faced forms. However, 



