Vol. 5, p. 51-58, pi. 5. June 8, 1923. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



A REVIEW OF THE PLATYPEZIDAE OF EASTERN NORTH 

 «. AMERICA. 



BY CHARLES W. JOHNSON. 



This family comprises an interesting group of little flies, the 

 larvae of which, as far as known, live in various species of decaying 

 fungi. Most of the species are by no means common and it has 

 taken several years to get sufficient material of the genus Platy- 

 peza to warrant an attempt at a revision. The species of Aga- 

 thomyia and Callimyia were reviewed by the writer in 1916 

 (Psyche, vol. 23, p. 27-33). The table of the species of Aga- 

 thomyia has been revised so as to include the three new species here 

 described. In the genus Callimyia no additions of importance 

 have been obtained and the table is therefore not reprinted in 

 this paper. 



The two sexes of a species in the genus Platypeza often differ so 

 greatly, both in color and in the form of the hind tarsi, that it is 

 difficult at first to correlate them specifically. The third tarsal 

 joint which is elongated and flattened below in the female, is not 

 thus differentiated in the male and when a study of the tarsi is 

 confined to one sex, the differences are so slight that they are of 

 little value even for separating species. Thus we find that the 

 female of P. pallipes is in every way, a typical Platypeza. Color is 

 also a feature that has lead to some confusion, and which I shall 

 again refer to under the several species here discussed. The 

 most valuable character to depend on is the venation, and when 

 studied carefully and with some discretion, the species can be 

 separated and the sexes correlated. The relative length of the 

 costal and first basal cells, the position of the posterior cross-vein 

 and the form of the anal cell are subject to but little variation 

 specifically. The following notes on the species of Platypeza are 

 based on a study of over 250 specimens, many of which were bred 

 from fungi. 



Table of the Species of Platypeza. 



Males. 



1. Hind tarsi greatly enlarged, first and third joints with clubbed appendages 



(Calotarsa ornatipes auct.) pallipes Loew. 



Hind tarsi somewhat enlarged, without appendages 2. 



51 



