128 DIPTEKA. 



appendage at the tip. Thorax with a pale fulvous fringe of hairs in front and on the sides, that on the 

 latter passing under the wings, where it becomes whitish-yellow, and strongly contrasting with the black 

 of the pectus ; the thoracic dorsum, besides the usual pile, shows a rare, appressed, easily rubbed off, 

 reddish tomentum. Scutellum with a conspicuous band of whitish tomentum at the base. Abdomen rather 

 evenly covered with a dense, appressed, fulvous tomentum ; the black, triangular spaces, occupying nearly 

 the whole middle of segments 3 and 4 (sometimes also 2), show but very few fulvous hairs, which form an 

 indistinct stripe in the middle. Yenter black, beset with black hair. Legs dark chestnut-brown. Knob 

 of the halteres pale yellow. Wings brown (not very dark) on the antero-proximal, and hyaline on the 

 postero-distal portion ; the brown does not quite cover the extreme end of the axillary and anal cells, 

 almost reaches the middle of the discal cell, occupies a small space at the proximal end of the first posterior 

 and first submarginal cells, and reaches the costal cell at the tip of the auxiliary vein — thus the extreme 

 end of the subcostal cell remains hyaline ; the] edge of the brown is rather jagged ; in the brown 

 there are some subhyaline or simply paler spots — at the proximal end of the second anal cell, within 

 the second anal, near the proximal end of the discal (the usual spot rather large here), in the middle 

 of the first anal, and on the anterior and posterior cross- veins; moreover, the innerjside of all the 

 cells is a little paler. The contact of the discal and fourth posterior cells is narrow, shorter than the 

 anterior cross -vein. 

 Length 7-12 millim. 



Hab. Mexico, Northern Sonora (Morrison). 



Twenty specimens of both sexes. 



A. parvicornis, Loew, Cent. viii. no. 36 (Illinois), is exceedingly like A. rex, and I was 

 somewhat tempted to regard the Sonoran insect as the same species. I have an example 

 of A. parvicomis before me which I believe to be correctly determined, because I 

 compared it with the type in Cambridge, Mass. ; it agrees with two others from 

 Dallas, Texas, and with some specimens from the same locality which I have seen 

 unnamed in the Berlin Museum. All these differ from my numerous representatives 

 of A. rex in having large tufts of yellow hair on the pleurae, between the humerus 

 and the middle coxae (this agrees with Loew's description) ; while in A. rex there is a 

 tuft of yellow hairs on the humerus, extending backwards to the root of the wing, but 

 the hairs below this tuft are black. The face and legs in those specimens which I refer 

 to A. jparvicornis are rufous. The scutellum described by Loew as "prseter basim 

 nigram obscure rufum," has sometimes that colour, but is sometimes nearly black. 

 Loew omits to describe the band of whitish tomentum at the base of the scutellum, 

 which was probably abraded in his specimen ; the coloration of the wings is the same in 

 both species. 



N.B. — A. rex and A. jparvicornis, on account of the structure of the antennae (which 

 are like those of Lepidanthrax) and the prolonged proboscis, belong to a distinct, some- 

 what aberrant group. The front tibia? are beset with spinules, principally on the 

 upperside ; the front tarsi have distinct joints, and are moderately stout. No pulvilli. 

 Front comparatively broad, broader in the female. 



Subgenus Anthrax. 

 Front tibia? provided with minute spinules ; front tarsi rather stout, furnished on both 

 sides with the characteristic delicate, erect pubescence, the joints distinct ; in some species 



