EPACMTTS.— APHCEBANTUS. U3 



Besides these examples I have seen several others (two males, four females) from 

 Tehuacan, Mexico (Sumichrast, in coll. Bellardi) which are a little larger ; have a 

 distinct stump on the upper branch of the third vein (one of them, however, with a 

 rudiment only of such a stump, and one of the females no stump at all) ; the row of stiff 

 bristles along the oral edge rather long, dense, intensely black, and for this reason much 

 more conspicuous than in the other specimens ; the wings more or less infuscated at the 

 base and along a part of the costa ; and the row of black bristles overshadowing the 

 male forceps (and mentioned in Loew's description) being particularly conspicuous. 

 Nevertheless these two males, as well as one of the females, do not show a trace of 

 the depression, or emargination, in the middle of the scutellum which Loew describes, 

 and which exists in the other specimens. (All these Mexican specimens are very 

 mouldy, and unfit for a closer comparison.) I incline to believe that E. modestus is a 

 very variable species ; but the question of the identity of the Tehuacan specimens I leave 

 in abeyance. That they belong to this genus is certain ; and therefore it is equally 

 certain that the absence of a stump and the presence of the emargination on the scutellum 

 should be struck out from among the generic characters. But whether that emar- 

 gination is a specific character, or merely an individual aberration, I cannot tell. The 

 principal characters of Epacmus may at present be summed up as follows : — 1. The 

 bifurcation of the second and third veins taking place not far from the origin of the former, 

 and a long distance before the small cross-vein. 2. The glabrous eyes being contiguous 

 in the male, with a comparatively large triangular front between them and the antennae. 

 3. Antennae: basal joints short ; third joint unsymmetrically short onion-shaped, pro- 

 longed in a style which ends in a very minute bristle. 4. Oral opening large, elongated, 

 elliptical, patulous posteriorly ; proboscis elongated, projecting beyond the oral margin, 

 linear, ending in narrow lips (thus producing an almost imperceptible incrassation). 

 5. Face short, projecting in the profile in front of the eyes. 6. Legs beset with delicate 

 spines. 7. Pulvilli none. 8. Posterior cells open ; anal cell usually open (almost closed 

 in some specimens) ; upper brau h of the third vein with or without stump. 9. The 

 abdomen of the male rather naruw, almost club-shaped at the end, the club being 

 formed by the large male forceps, the two halves of which seem to be encased in the 

 cup-shaped last ventral segment ; that of the female showing at the end the circle of 

 converging hairs common to many genera of the present group. 



Forms related to Epacmus, and also to Aphcebantus, occur in Central Asia (Berlin 

 Museum, from Loew's collection). 



APHCEBANTUS. 



Aphcebantus, Loew, Centur. x. no. 39 (1872) . 



Besides Epacmus (Leptochilus, Loew) the western regions of the United States, as 

 well as Northern Mexico, contain a number of closely allied species belonging to the 

 group in which the bifurcation of the second and third veins takes place some distance 



