146 CALIFORNIA ACADEMY OF SCIEHCES. [Proc. 3D Ser. 



transverse vein is iess distant from the margin of the wing 

 than its own length ; the end of the fourth longitudinal vein 

 is paraliel with the third. Feet with rather coarse bristles; 

 the first joint of all the tarsi is much longer than the 

 second; the first joint of the hind tarsi without bristles." 



In all these characters the Californian species agree with 

 their European congeners. They may be distinguished from 

 one another thus: 



a. Arista of the antenna naked, posterior cross-vein at right angles to the 



fourth vein b. 



Arista pubescent, posterior cross-vein forming an obtuse angle with the 



fourth vein Aphrosylus grassator. 



b. Wing with a black blotch covering the distal end of the discal 



cell, fore and hind femora ciliated above A. direptor. 



Wing without a black blotch, fore and hind femora eciliate. 



A. prczdator. 



Aphrosylus praedator, sp. nov. 



Plate IV, Figs. 1-6. 



Male. — Length of body 2-3 mm; length of wing 2.5-3 mm - Antennas 

 black, first joint rapidly widening distally, second short, spheroidal, with 

 black bristles, third tapering rather uniformly from a broad base to a point, 

 and covered with short hair and with a few scattered, short, spine-like bris- 

 tles, which are more numerous on the ventral than on the dorsal surface. 

 The two-jointed arista is long and flexuous, its basal segment about one-third 

 as long as the third antennal joint and, like this joint, covered with short 

 hairs; the apical segment bare. Face metallic green, thickly covered with 

 gray dust, narrow towards the middle where there is a distinct indentation at 

 the orbit on either side. The lower portion of the face projects forward 

 somewhat. Palpi large, black, with black hairs. Proboscis swollen, cylin- 

 drical. Posterior orbit metallic green, with thick gray dust and black cilia. 

 Thoracic dorsum metallic green overlaid with a thick layer of brown dust; 

 the dorsal and acrostichal bristles prominent, black. Pleurae black, with or 

 without very slight metallic green reflection, covered with gray dust. Scu- 

 tellum of the same color as the thoracic dorsum, with four bristles, the me- 

 dian pair long and thick and directed upwards and forwards; the lateral pair 

 small and weak and directed backwards. Abdomen suddenly narrowed at 

 the fourth segment, above metallic green, somewhat less opaque than the 

 thoracic dorsum, and covered with black hairs, below blackish and covered 

 with pale dust and hairs like those on the dorsal surface. What is to all ap- 

 pearances a rudiment of the seventh abdominal segment overlaps the base of 

 the hypopygium on the left side. Hypopygium large, its swollen base black, 

 without hairs; the pair of external appendages bent forwards at a right angle 



