1898.] NATURAL SCIENCES OF PHILADELPHIA. 173 



tliia number occurs occasionally in otherwise normal specimens both 

 of domestica and corvina. 



Musca corvina Fabr. 



One male taken September 10, 1894. 

 Musca biseta nov. sp. 



One male and four females, all taken March 10, 1894. Very 

 much like domestica, from which it differs as follows: 



Male. — Front about one-half as wide as in specimens of domestica 

 with the same width of head. Dorsum of first abdominal segment 

 entirely black. 



Female. — Front of same width as that of specimens of domestica 

 with same width of head, but the frontal vitta is decidedly narrower 

 and its lateral borders less curved. 



Both Sexes. — Smaller than the average sized domestica. Geno- 



vertical plates, genre, bucc?e and vibrissal ridges silvery white, with 



scarcely a trace of the yellowish tinge which so often predominates 



in domestica. Only two dorso-central bristles in front of the suture. 



Bristles of the extenso lateral row of the hind tibia equal or almost 



equal. No prominent bristle in the extenso-mesal row of the hind 



tibia. 



Genus MORELLIA. 

 Morellia podagrica Loew. 



Two males and one female taken March 10, 1894, and April 10, 

 1894. Agree perfectly with, but are smaller than, my European 

 specimens of this species. 



Genus PSEUDOPYRELLIA. 

 Pseudopyrellia sp. ? 



One male and one female taken March 10, 1894. This is a 

 new species. The specimens are too imperfect to describe fully. 

 The antennal arista has longer, more numerous and more delicate 

 hairs than comicina (American and European specimens), and the 

 female has on the thorax, in front of the suture, a broad, median, 

 cephalo-caudal hoary stripe which fades out before the suture is 

 reached. The distinctness and brilliancy of this stripe vary with 

 the iucidence of light. Of 100 American female specimens of com- 

 icina examined not one has this stripe. The front of the male is 

 much narrower than in comicina. 



Pseudopyrellia nuda nov. sp. 



Four females taken March 10, 1894, and September 29, 1894. 

 Length about 8 mm., of a brilliant metallic violet color, varying to 

 bronzy-green. Remarkably few and delicate macrochsetse. 



