154 . DIPTEBA. 



brownish, those on the posterior half darker. Legs black, with a not very dense 

 covering of yellowish scales. Knob of the halteres yellow. Wings hyaline, brownish at 

 the base. 



A male specimen of this interesting species has been kindly given to me by 

 Dr. Williston, of New Haven, Conn.] 



SPARNOPOLIUS. 



Sparnopolius, Loew, Neue Beitr. &c. iii. p. 43 (1855). 



Specimens in Prof. Bellardi's collection (Mexico, Truqui) may perhaps belong to 

 S. brevicornis, Loew, Centur. x. no. 43 (Texas, Belfrage). 



LORDOTUS. 



Lordotus, Loew, Centur. iv. no. 53 (1863). 



Loew only described the female ; the male has contiguous eyes, and the edge of the 

 costa denticulate on the distal half. The genus is easily distinguishable by the enormous 

 expansion of the end of the marginal cell. In the male I count eight abdominal segments, 

 besides the forceps ; the eighth segment is short, and more or less withdrawn within 

 the preceding one ; the forceps withdrawn within the abdomen in the usual un sym- 

 metrical fashion, with the opening of the ring turned towards the right. 



In one of the female specimens I can count only five segments ; in another, a large 

 sixth and a small seventh segment are extruded ; the ovipositor does not show the 

 coronet of spinules, but, as far as I can see, there is a small bifid horny plate, with the 

 two ends rounded. 



1. Lordotus gibbus. 



Lordotus gibbus, Loew, Centur. iv. no. 53 ; O. Sacken, Western Dipt. p. 258 \ 

 (?) Adelidea flava, Jaennicke, Neue exot. Dipt. p. 39 ; O. Sacken, Catal. N. Am. Dipt. 1878, p. 93, 

 note 162. 



Hab. North America, Western United States 1 . — Mexico, Northern Sonora (Morrison), 

 Tehuacan (Sumichrast, in coll. Bellardi). 



I have shown in the ' Western Diptera ' that this species is variable as to the colour 

 of the antennae and legs, and that for this reason many specimens do not quite agree 

 with Loew's description. I have before me several specimens from Mexico, and a 

 single small one from Northern Sonora. In the latter the wings are hyaline, without 

 that yellowish-brown shade in the antero-proximal region which distinguishes normal 

 examples. Smaller specimens with a whitish, instead of yellow, fur are perhaps faded 

 representatives of the same species. 



