NOTES ON NE ARCTIC PSYCHOMYIIDAE — FLINT 471 



below Old Hickory Dam in about 15 feet of water, also on rocks. It 

 apparently can take the range of flow from practically standing water 

 to quite rapidly flowing water. On these rocks it lives under an 

 amorphous silk mat usually silt covered." 



Genus Nyctiophylax Brauer 



The genus is found throughout the world with the exception of 

 Australia-New Zealand and Europe, although it is well represented 

 in the Baltic Amber. In North America there are at least 5 closely 

 related species. Larvae of this genus were first described by Noyes 

 (1914) as Cyrnus pallidus (?), and later by Ross (1944) as Genus A 

 and Genus B. Ulmer (1957) described the larvae and pupae of the 

 Sumatran A^". -flavus. Generic characters of the larvae are given below: 



Head about as wide as long; muscle scars pale. Labrum over 

 twice as wide as long (fig. 2,d). Mandibles with dorsal edge over- 

 hanging ventral edge, left mandible with mesal brush (fig. 2,c). 

 Pronotum sclerotized, with pale muscle scars; mesonotum and meta- 

 notum membranous. Forefemora with stout dark setae ventrally 

 and anteriorly; foretibiae with 3 stout dark setae posteriorly and 4 

 anteriorly; midtibiae with 3 stout dark setae both posteriorly and 

 anteriorly (fig. 2,e~i). Ninth segment ventrally with a T-shaped 

 area of small spicules. Basal segment of anal prolegs with spicules 

 basoventrall}^; and long hairs apically and apicomesally (fig. 2,k). 

 Anal claw with strong teeth ventrally, and an accessory tooth ex- 

 ternally (fig. 2.j). 



The pale muscle scars of the head and pronotum and enlarged 

 dorsal margin of the mandibles relate the genera Nyctiophylax, Cyr- 

 nellus, and the one described here as Genus C. The short, broad, 

 and black setae on the legs also indicate a close relationship between 

 Nyctiophylax and Genus C, as do the ventral teeth on the anal claw. 

 The larvae of Nyctiophylax dift'er from those of Genus C in having 3 

 dark setae posteriorly on the midtibiae and hind tibiae, setae ven- 

 trally on the basal segment of the anal proleg, and a dorsal brush on 

 the apical segment; also in having the ventral teeth shorter and 

 farther from the base on the anal claw as weU as an external tooth 

 on the claw. 



Key to Larvae of Genus Nyctiophylax 



1. Dark color on genae completely enclosing frontoclypeus posteriorly, species A 

 Dark color of the genae not meeting broadly posterior to frontoclypeus . . 2 



2. Dark color extending anteriorly along frontal sutures to anterior margin of 



the head N. nephophilus 



Dark color of head not reaching anterior margin N. vestitus 



