142 DIPTERA. 



the proboscis protrudes a little beyond the oral margin, and has much narrower lips ; 

 the anal cell is open ; the antennae of the known species have a somewhat different struc- 

 ture, the third joint being stouter at the base and more suddenly attenuate (but the last 

 two characters may be merely specific). The differences in the general characters 

 and in the nature of the hairy covering are obvious. 



The genital organs are very much alike in structure in both genera: the male 

 forceps withdrawn symmetrically within the abdomen ; the ovipositor with a thick 

 covering of silky fibres like that of Bombylius. In both genera there are no macrocheetse 

 on the scutellum and post-alar callosities differing in size from the other hairs ; two 

 or three macrochsetse are perceptible on the prae-alar callosities only. In this respect 

 Lomatia and Oncodocera differ from the majority of the " Anthracina." 



1. Oncodocera valida. CZ^ 



Anthrax valida, Wiedem. Aussereur. zweifl. Ins. ii. P.-647 1 . ' «-^- A -^-°' 

 Anisotamia eximia, Macq. Dipt. Ex. Suppl. iv. p. 114, t. ll.f. 2 2 . 

 Oncodocera valida, O. Sacken, Catal. N. Am. Dipt. 1878, p. 90. if 



Hab. Mexico x 2 (Sumichrast & Craveri, in coll. Bellardi) ; Guatemala, San Gerommo 

 (Champion). 



I have a pair from the latter locality before me; both specimens are entirely 

 abraded. 



2. Oncodocera lencoprocta. , , , 



Mulio leucoprocta, Wiedem. Aussereur. zweifl. Ins. i. p. 330 ( $ ) (sine patria) . ^ ' ¥ ^ * "*" 



Anthrax terminalis, Wiedem. loc. cit. ii. p. 639 \ 



Ogcodocera dimidiata, Macq. Dipt. Ex. ii. 1, p. 84, t. 15. f. 1 ( ? ). 



Oncodocera leucoprocta, O. Sacken, Catal. N. Am. Dipt. 1878, p. 90. 



Hab. kSouTHERN United States. — Mexico 1 . 



EPACMUS*. 



Leptochilus, Loew, Centur. x. no. 40 (1872) (nomen prseocc.). 



The name Leptochilus being preoccupied in Hymen optera (Saussure, 1852), I am 

 obliged to adopt a new generic name in place of that of Loew. 



1. Epacmus modestus. 



Leptochilus modestus, Loew, Centur. x. no. 40 \ 



Hab. United States, Texas \ California. — Mexico, Northern Sonora (Morrison). 



Loew is quite right in describing the hairs above the oral margin in the female of 

 this species as " non raro ferrugineis, vel fuscis, interdum nigris." My few specimens 

 show these differences. 



* iiraKfxos, pointed. 



