OSTEN SACKEN ON WESTERN DIPTERA. 303 



white and black hairs ; the subhuineral callosities and the lower part of 

 the pleurae are beset with white hairs ; but, in front of the root of the 

 wings, there is some black pile. The abdomen on the sides is beset 

 with white pile ; it is long and tuft like at the base, but becomes rather 

 rare beyond the third segment. Legs uniformly deep black, shining ; 

 they are much less stout than in G. callipedilus 9; the tibiae, especially 

 the front pair, are more straight ; front tarsi rather long ; the pile and 

 bristles on the four anterior legs are black, except some white pile on 

 the under and hind side of the femora ; the hind femora and tibiae are 

 beset with white pile, which is particularly dense on the upper side of 

 the hind tibiae; the bristles, as usual, are black; the first joint of the 

 hind tarsi shows, in a reflected light, some short, white pile ; otherwise 

 the tarsi are uniformly black. Ungues whitish, with black tips. Wings 

 grayish-hyaline ; venation normal. Length 10.5 ram . 



Sab. — Webber Lake, Sierra Nevada, California, July 22. Two females. 

 A third specimen, from the same locality, has the third antennal joint 

 much darker reddish-brown; the thoracic dorsum has distinct brown 

 stripes, and is less whitish ; the fan-like fringe of pile in front of the 

 halteres consists of black hairs only, etc. I believe, nevertheless, that 

 the specimen belongs to C. cretaceus. 



This species, like G. princeps, has the ungues whitish, with black tips ; 

 both species were found in the same locality ; they are too different, 

 however, to be taken, without further evidence, for the sexes of the 

 same species. The other species of Gyrtopogon, described in this paper, 

 have the ungues black and more or less brownish or reddish at the base 

 only. G. profusus and nugator are the only species which, in this re- 

 spect, resemble the two above-mentioned ones. 



9. Cyrtopogon longimanus Loew, Berl. Ent. Zeitschr, 1874, 360 ; 



"Male. — Totus ater, pilis nigris et albis vestitus, vittis dorsalibus tho- 

 racis tribus latissimis fusco-pollinosis, segmentis abdominalibus secundo, 

 tertio, quarto et quinto singulis postice fascia lata albo-pollinosa ornatis, 

 alarum dimidio basali hyalino, apicali nigricante. — Long. corp. 4^ lin. 

 long. al. 3 T 5 2 lin. (about 9 mm and 7.5 mm ). 



(Translation.) " The ground-color of the whole body is, without excep- 

 tion, shining black. The front with a long black pubescence, with which 

 are mixed some whitish hairs, or such which appear whitish toward 

 their tip. Antennae black, the two first joints sparsely beset with 

 black hairs, partly whitish toward their tips; the third joint very slender, 

 strongly coarctate in the middle ; terminal style slender, a little more 

 than half as long as the joint. The long mystax reaches up to the 

 antennae, and is composed in the middle of hairs which are whitish, 

 or black at their base only ; the hairs on its outer side, all around, are 

 exclusively black, so that, seen from the side, the mystax seems to con- 

 sist entirely of black hairs; the long pile on the occiput is white; in 

 the vicinity of the vertex and on the greatest part of the posterior 

 orbit, it is black. The pollinose design on the thoracic dorsum resem- 

 bles that of G. marginalis Lw. It consists of three broad stripes cov^ 



