76 AMERICAN DIPTERA. 



Aiioroi^tonia opacsi Coquillett. 



" Head yellow, opaque, white pruinose, the front and upper part of the occiput 

 tinged with bluish gray, a velvet-black spot between the antennae and each eye, 

 anteiinte brownish, the arista marked before the middle with a white ring, palpi 

 yellow, proboscis brown ; body brown, opaque, bluish-giay pruinose, mesonotum 

 with four, the pleurae with one brownish pruinose vittse ; sternopleura bearing 

 numerous short bristly hairs and with two stout bristles; legs yellow, opaque 

 grayish pruinose, except a polished spot at base of the posterior side of the first 

 two pairs and a streak on the posterior side of the hind ones; wings whitish, 

 marked with large pale gray spots and with a black cloud covering the small and 

 hind cross-veins, a small black spot beneath apex of auxiliary vein, one slightly 

 before middle of antepenultimate section of the fourth vein, and several smaller 

 spots on some of the other veins; the gray color fills the whole maiginal cell 

 beyond apex of auxiliary vein, nearly the entire second half of the submarginal, 

 etc.; length 7 mm. A female specimen captured by the writer. 



"Habitat. — Los Angeles County, Cal. 



•' Type.— Cut. No. 5500, U. S. N. M." Original description. 



This species is not represented in the material examined. From 

 its resemblance to maculata, it is probably a sand dune form, 

 although nothing has been reported about its habits. 



Aiiorostoina maculafa Darlington, n. sp. (PI. IV, figs. 4 and 5). 



Length 4.5 mm.; of wing, the same. 



General color gray, wings spotted, cheeks ci'eam colored. 



Occiput, vertex and front gray ; lower pait of the front somewhat yellowish 

 and pubescent; the two pairs of veitical and three pairs of fronlo-orbital bristles 

 arise from brown spots; a rather broad brown stripe extends from the ocellar 

 bristles to the base of the occiput; antennae brown, third joint oval, arista white 

 for about one-third its length at the proximal end ; cheeks about one and a half 

 times the width of the eye; eyes transversely ovate; a black spot connects the 

 base of the antenna with the anterior somewhat angular margin of the eye; 

 vibrissse rather small. 



Thorax gray; dorsum ash-gray; the dorsocentral bristles arise from large, 

 distinct brown spots and the small hairs arise from small brown dots; the 

 humeri, the lateral edges of the thorax, and the pleurae, have a reddish-gray 

 tinge; scutellutn gray, bare except the ordinary four bristles, which arise from 

 large brown spots, the apical pair confluent; the mesopleura has one large and 

 one small bristle on the posterior edge, otherwise bare; the sternopleura with 

 one strong bristle on the upper edge and with rather long, somewhat scattering 

 pubescence below. 



Abdomen gray, the small hairs arising from brown dots; hyiioj)ygium of the 

 male gray, globose, and sparsely covered with very short pubescence. 



Wings whitish, with large brown blotches; there is a blackish spot on the 

 auxiliary vein at its tip, one on the small cross-vein, and a small one on the 

 anterior end of the hind cross-vein, forming a straight row ; the posterior end of 

 the hind cross-vein also a little iufuscated. 



Legs pale yellow, except the femora, which are gray. 



