NORTH AMERICAN DIPTERA. 179 



11. A. inolitor Loew. 



The Colorado specimens referred to in my monogi-ai)h belong to 

 agrlppina O. S. (No. 61). The forms pretiosa Cah\. and vacans Coq. 

 which I regarded as varieties of molitor, are certainly distinct, and 

 are fully characterized herewith. 



lla. A. pretiosa n. sp. — (Syn. A. molitor var. pretiosa Coq.) — Black. Frout 

 sparse, yellowish white tomentose and black pilose, face greatly retreating 

 below, yellowish white tomentose and light yellow pilose. Proboscis not pro- 

 jecting. Antennae with first joint twice as long as the second, black pilose 

 above, that below largely yellow, base of third joint short-conical. Occiput pure 

 white tomentose, that in the middle above pale yellowish. Thorax mixed black 

 and yellow tomentose, the bristles reddish, pile of front end, sides, and upper 

 part of pleura golden-yellow, that on lower part of pleura, breast and coxa* light 

 yellow, sometimes almost white. Scutellum mixed black and golden-yellow 

 tomentose, that around the edges golden-yellow, the bristles reddish, but some- 

 times a few are black. Abdomen black and golden-yellow tomentose, the black 

 being on first segment (scanty), on apices of second, third and fourth segments, 

 and on bases of the fifth and sixth segments; last segment never silvery tomen- 

 tose in the male; pile of dorsum very sparse, black and reddish, that on the 

 sides dense, golden-yellow, that on sides of fifth and sixth segments sometimes 

 black; venter golden-yellow, or yellowish white tomentose; that at bases of 

 fifth and following segments narrowly black. Legs golden-yellow, or yellowish 

 white, tomentose. that in front partly black ; front tihiiP provided with bristles, 

 claws of front tarsi about one-half as long as those of the middle tarsi in the 

 female, but only one-third as long as in the male. Wings hyaline, costal and 

 usually the first basal cell yellowish ; base of wings of female in front golden- 

 yellow tomentose, that aloTig the outward edge black ; in the male provided with 

 silvery scales, and with a silvery epaulette. Length 10—14 mm. 



Southern California. Nineteen specimens in July. 



lib. A. vacans n. sp.— (Syn. A. molitor var. vacans Coq. )— Black. Front 

 yellowish tomentose and black pilose; face slightly produced below, yellowish 

 tomentose. Proboscis not projecting. Antennje with first joint twice as long 

 as the second, black pilose above, yellowish pilose below; base of third 

 joint short-conical. Thorax mixed black and brassy-yellow tomentose, bristles 

 reddish, pile of dorsum black, that on front end, sides and pleura yellowish 

 white, that on breast and coxae largely black. Scutellum mixed black and brassy- 

 yellow tomentose, bristles black. Abdomen black ton)entose, that on first seg- 

 ment and bases of the second and fourth segments pale yellow, that on the fourth 

 segment forming a distinct cross-band ; pile of dorsum rather abundant, mixed 

 yellowish white and black, that on the sides very abundant, erect and bushy, 

 yellowish white, except that on sides of segments five and six and on apex of 

 the last segment, which is black ; venter mixed black and yellowish tomentose 

 and pilose. Legs largely blac^k tomentose in front, dark yellow tomentose be- 

 hind ; front tibiai provided with bristles, claws of front tarsi less than half as 

 long as those of the other tarsi. Wings hyaline, costal cell yellowish, base of 

 wings in front largely black tomentose. Length 18 mm. 



Washington. A single female specimen. 



TRANS. AM. ENT. SOC. XIX. JULY, 1892. 



