NOTES ON NE ARCTIC PSYCHOMYIIDAE — FLINT 469 



I wish to express my appreciation to Dr. H. H. Ross, of the Illinois 

 Natural History Survey, and Dr. S. S. Roback, of the Philadelphia 

 Academy of Natural Sciences, for their loan of specimens. Dr. P. J. 

 Darlington, Jr., of the Museum of Comparative Zoology at Harvard 

 University, made it possible for me to study the Banks types of 

 Cy melius. The material used in this study is from four sources: 

 Illinois Natural History Survey (INHS), Academy of Natural Sciences 

 of Philadelphia (ANSP), United States National Museum (USNM), 

 and the author's collection (OSF). 



Key to the Genera of Psychomyiidae Based on the Larvae 



1. Foretrochantin broad, hatchet-shaped, set off by a basal suture (Psychomyii- 



nae) 7 



Foretrochantin pointed, fused to pleuron (Polycentropodinae) 2 



2. Both mandibles with a linear brush mesally, and equilateral in outline; tarsi 



broad and densely pilose Phylocentropus 



Right mandible never with a brush, and distinctly longer than broad; tarsi not 

 pilose 3 



3. Muscle scars of head and pronotum as pale or paler than surroundings ... 4 

 Muscle scars darker than surroundings 6 



4. Anal claw with well-developed ventral teeth 5 



Anal claw without ventral teeth Cyrnellus 



5. Anal claw with ventral teeth much shorter than apical hook and with an ex- 



ternal tooth; foretibiae and midtibiae with 3 short dark setae on posterior 



face Nyctiophylax 



Anal claw with ventral teeth nearly as long as apical hook, no external tooth; 

 foretibiae and midtibiae with 1 short dark seta on posterior face. 



{Cernotinai) Genus C 



6. Basal segment of anal proleg without setae Neureclipsis 



Basal segment of anal proleg with setae Polycentropus 



7. A broad fiat process anteriorly from mesopleuron; tibiae and tarsi fused. 



Xiphocen tron 

 No process on mesopleuron; tibiae and tarsi distinct 8 



8. Anal claw with several long teeth ventrally Psychomyia 



Anal claw lacking ventral teeth 9 



9. Left mandible with linear brush; mandibles distinctly longer than broad. 



Tinodes 

 Left mandible with 2 discrete brushes; mandibles equilateral in outline . . Lype 



Cyrnellus fraternus (Banks), new combination 



Figure 1 



Cyrnus fraterna Banks, 1905, p. 17. 



Nyctio-phylax fraternus. — Ross, 1938b, p. 12 (designates lectotype). 



Nyctiophylax marginalis Banks, 1930, p. 231. — Ross, 1938b, p. 12 (designates 



lectotype). New synonymy. 

 Cyrnellus marginalis. — Ross, 1944, p. 71 (male and female).— Sublette, 1957, 



p. 378 (mentions larvae). — Ross, 1959, p. 1033 (keys larvae). 



I recently had the opportunity to study the lectotypic female of 

 raternus and found that its forelegs had a preapical spm* and its 



