186 PROCEEDINGS OF THE ACADEMY OF [1898. 



vibrissal angle and principal vibrissa a little above the mouth edge 

 but not as high as in Compsomyia macellaria or in Pollenia; the 

 principal vibrissa is very small for the size of the fly ; there are no 

 other vibrissa? but the ridges are clothed nearly their whole length 

 with exceedingly minute whitish hairs. 



The arista is about as long as the third antennal joint and is 

 densely plumose with fine hairs. Its rhachis is yellow toward the 

 base while its apical part and the hairs appear black. 



Thorax. — Color. — Metallic blue, violet or green with hoary coat- 

 ing. The hoary coating is much thicker in front of than behind the 

 suture. The prostigma is very large and is white. Halteres yellow- 

 ish. Tegulse wbite with smoky brown or black border of very vary- 

 ing width. 



Bristles. — There is a row of bristles on the hypopleura and some 

 bristles on the pteropleura. 



Abdomen. — Color. — Metallic blue, violet or green with a hoary 

 coating which is thickest toward the sides and on the ventral sur- 

 face. The first segment and the caudal borders of the second and 

 third are not hoary. The fourth segment is quite thickly covered 

 with whitish hairs. There are no abdominal macrocbretse. The 

 second ventral plate overlaps the corresponding dorsal plates a very 

 little, the other ventral plates are overlapped by the corresponding 

 dorsal plates. 



Br-istles of the Legs. — Femora as usual in the Muscidse. Tibia? : 

 anterior tibia has on the mesal surface in the extensor row three 

 prominent bristles III, 4, and on the lateral surface in the flexor 

 row one III, 5 ; middle tibia has on the anterior surface one III, 6 

 on the posterior surface three III, 7, and on the flexor surface one 

 III, 8 ; hind tibia has on the lateral surface in the flexor row two 

 III, 9, and on the mesal surface, in the extensor row, one III, 10. 



Explanation of Figures. 



I. 



1. Cross section of anterior femur of a Muscid. 



2. Formation of an oblique row of bristles on the tibia. 

 3a. Bristles of thorax of Pseudopyrellia nuda nov. sp. 



3b. Bristles of sternopleura of Pseudopyrellia nuda nov. sp. 



3c. Bristles of mesopleura of Pseudopyrellia nuda nov. sp. 



4. Wing of Pseudopyrellia nuda nov. sp. 



5a. Bristles of thorax of Pollenia virido-cana nov. sp. 



5b. Sternopleura of Pollenia virido-cana nov. sp. 



5c. Mesopleura of Pollenia virido-cana nov. sp. 



