PSYCHE 



VOL. XXVII OCTOBER. 1920 No. 5 



SYNOPSIS OF THE DIPTEROUS FAMILY PSILIDiE.^ 



By a. L. Melander, 

 Pullman, Washington. 



The following keys are given to assist in the determination of the 

 flies of the family Psilidse as at present known from North America. 

 The study is based entirely on my own collection, species before me 

 being indicated by starring the localities represented. In the 

 February (1920) issue of Psyche Mr. Charles W. Johnson gives 

 tables of Loxocera and a new genus, Pseudopsila. With slight 

 modifications these tables are incorporated in the present paper. 



Table of Genera. 



1. Antennae greatly lengthened, longer than the head, the third 



joint very slender, more than four times the length of the 



second joint and distinctly longer than the arista; no 



fronto-orbital or postvertical bristles.. .Loxocera Meigen 



Antennae shorter, the arista longer than the third joint ... .2 



2. Third antennal joint subcylindrical, about three times as long 



as the second; no fronto-orbitals, but postverticals present, 



one presutural dorsocentral present . . . Pseudopsila Johnson 



Third antennal joint short, ovate, rounded 3 



3. Face very strongly retreating; anal cell as long as second 



basal P.s'i7a Meigen 



Face more nearly perpendicular, the head not triangular in 

 profile 4 



4. Robust; occiput flat, ocellar triangle small and placed well 



back; 4 scutellar bristles; pteropleurse bare; first vein 

 ending opposite anterior cross vein, second vein near wing- 

 tip, anal cell shorter than second basal and truncate 



Chyliza Fallen 



Slender; head spherical, ocellar triangle placed forward; 



2 scutellar bristles; pteropleurae with hairs; first vein 



ending before anterior crossvein, second vein about midway 



1 Contribution from the Zoology Laboratory of the State College of Washington. 



