AKTll. NOTES ON NEARCTIC BIBIONID FLIES McATEE. 6 



Genus HESPERINUS Walker. 



HESPERINUS BREVIFRONS Walker. 



Hesperinus brevifrons Walker (Francis), List of the Specimens of Dip- 

 terous Insects in the Collection of the British Museum/ pt, 1, 1848, p. 81 

 [St. Martin's Falls, Albany River, Hudson Bay]. 



More slender than the average Bibionid, antennae and legs elon- 

 gate. Antennae twelve-jointed, second joint short, third about twice 

 as long as fourth ; general color of head and body black with grayish 

 pruinose markings, the chief elements of which are a broad median 

 and narrower lateral vittae on thorax, and a narrow median line on 

 abdomen; head and thorax with short, abdomen, with longer pale 

 hair; genital segment of male with a broad rounded cleft nearly 

 half its length; anal plate rounded emarginate; legs copiously 

 bristly-hairy, yellow brown, darker at end of joints especially on 

 tarsi ; halteres long, slender, stramineous ; wings dusky hyaline, veins 

 and stigma brown. Length of wings, 7 mm. 



Specimens examined are from Currant Creek Valley, elevation 

 8,000 feet, Uinta National Forest, Utah, June 25, 1917, J. Silver 

 (Biol. Survey). The species has been recorded also from New 

 Hampshire, Rocky Mountains and Alaska. 



This is one of the genera on the vague border line between the 

 Mycetophilidae and Bibionidae ; the long slender antennae and gen- 

 eral appearance ally it to the former, but the lack of conspicuous 

 spurs on posterior tibiae and presence of complete second basal cell 

 in wing connect it perhaps more closely with the latter. Johannsen ^ 

 ranges this genus with the Bibionidae, but Hesperodes, which Co- 

 quillett compared^ with it, he assigns to the Mycetophilidae. 



Genus PLECIA Wiedemann. 



KEY TO SPECIES. 



A. Both sexes with the face produced in a beak as long as remainder of head; 



top of thorax reddish yellow; pleura and coxae brown to black bicolor. 



AA. Species without beak. 



B. Whole of thorax and coxae yellow confusa. 



BB. Body and legs wholly black heteroptera. 



PLECIA BICOLOR Bellardi. 



Plecia bicolor Beixabdi (Luigi), Saggio di Ditterologia Messicana, pt. 1, 



1859, p. 16 [Cordova, Orizaba, Mexico]. 



Beak as long or longer than remainder of head, narrowed a little 



before apex where palpi are inserted; eyes large and contiguous in 



male, small and well separated in female. Top of thorax reddish 



5 References are given in full the first time cited and abbreviated tliereafter. 



6 The Fungus Gnats of North America, pt. 1, Bull. 172, Maine Agr. Exp. Sta., Dec, 

 1909, p. 222. 



7 Two New Genera of Diptera, Ent. News, vol. 11, No. 4, Apr., 1900, p. 429. 



