288 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



cittiens from California (San Eafael, Marin County, May 29; Sonoma 

 County, July 4) and Vancouver Island (G. R. Crotch), which are very 

 like I), alhius from the Atlani}ic States, but seem to differ in the abdo- 

 men being less narrow and less glabrous ; the scattered, fine, yellowish - 

 red pile of the abdomen, which is very little conspicuous in the Atlantic 

 specimens, is very distinct in the Californian ones. However, D. albkis 

 from the Atlantic States is subject to variations the limit of which is, 

 as yet, very doubtful to me. 1 have ten male and female specimens 

 before me from the Catskill Mountains, New York, from the White 

 Mountains, and from the Palisades, New Jersey, opposite New York. 

 Some of the males have the whole axillary region of the wing distinctly 

 whitish ; in others, this whitish tinge is very distinct on the whole prox- 

 imal half of the wing. One of the male specimens from the White 

 Mountains has the proximal two-thirds of the wings pale yellowish, the 

 distal third blackish, the tibiae yellowish-red except at the tip, the 

 front femora yellowish-red except a broad black stripe on their upper 

 surface. This specimen may be a distinct species, but it is singular 

 that the two specimens from Vancouver Island also have the base of 

 the tibiae yellowish-red; the femora, however, are altogether black. 

 The other Californian specimens show the same tendency to vary in the 

 coloring of the wings as the Atlantic specimens. In this uncertainty, I 

 prefer not to describe my Californian specimens until a larger number 

 can be procured. 



2. DiocTRiA RESPLENDENS Loew, Centur., X, 21. — California. I have 

 seen (in Mr. Burgess's collection in Boston) a specimen of this easily 

 recognizable species. 



3. DiocTRiA pusio n. sp., 9 .—Thorax and abdomen black; segments 

 3-5 of the latter, dull reddish; legs yellowish-red; hind tibiae dark 

 brown except the tip. Length 4.2""'. 



Antennae long, black, inserted on a small protuberance ; third joint 

 (without the style) as long as the first two taken together; the style 

 not quite half as long as the joint, with a small expansion at the base 

 (somewhat like Meigen, tab. 19, fig. 20, only the style, in comparison to 

 the joint, is longer in D. pusio) ; face with a pollen, which is golden-yel- 

 low above, silvery below; mystax of a few whitish hairs; front and occi- 

 put black; posterior orbits and two spots above the neck on the occiput 

 silvery-pollinose. Thorax black, shining ; dorsum with three faintly in- 

 dicated lines of microscopic pubescence; the lateral ones expanded into 

 triangles anteriorly ; pleurae with several spots with a partly silvery, 

 partly golden reflection. Knob of halteres lemon-yellow. Legs red, 

 including the coxae ; hind tibiae dark brown, except the tip, which is 

 red and somewhat incrassated ; first joint of hind tarsi large and stout. 

 Abdomen black, shining, smooth ; second segment with a greenish re- 

 flection ; the three following segments are reddish, but with darker, 

 metallic reflections. Wings with a rather uniform, slight brownish tinge ; 

 anal cell open; veins brown, yellowish at base ; venation normal. 



Mah. — Sonoma County, California, July 4. A single specimen. 



