472 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 115 



Nyctiophylax vestitus (Hagen) 



Figure 2 

 Polycentropiis vestihis Hagen, 1861, p. 293. 

 Nijctiophylax vestitics. — ^Ross, 1938b, p. 13 (designates lectotype); 1944, p. 70 



(male and female). 

 Genus b Ross, 1944, p. 74; 1959, p. 1032. 



Although the adults of this species are commonly collected at 

 lights throughout much of eastern North America, the larvae have 

 remained unknown until recently. Ross (1944) gave the first de- 

 scription of the larvae under the name Psychomyiidae Genus B. 

 In the summer of 1961 I collected a male metamorphotype of the 

 species, finally establishing the correlation of stages. 



Larva. — Length 8 mm. Head yellowish, with brown area neither 

 reaching anterior margin nor extending posteriad of frontoclypeus 

 (fig. 2,a). 



Material. — Illinois: Kankakee R., Momence, May 26, 1936, 

 H. H. Ross, 1 larva (INHS). Virginia: Broad Run, Thoroughfare 

 Gap, Fauquier County, July 22, 1961, O. S. FHnt, 1 larva, Icfpupa 

 (USNM); May 27, 1961, 27 larvae, 4 pupae (OSF); June 14, 1961, 

 1 larva, 1 pupa (USNM); Thornton R., above Sperryville, Mar. 

 4, 1961, O. S. Flint, 9 larvae (USNM); Apr. 15, 1961, 7 larvae 

 (USNM). North Carolina: Deep Creek, 2,000 ft., near Bryson City, 

 May 19, 1959, O. S. Flint, 1 larva (OSF); June 7, 1961, 1 larva 

 (USNM). 



Remarks. — There is considerable variation in the shape of the 

 clasper of the male. It may well be that further study will show 

 that our present concept of the species includes several closely related 

 species. For this reason, I give figure 21, showing the clasper from 

 the metamorphotype. In all likelihood the name vestitus, based on a 

 female, is correctly associated with this male as the type locality is 

 Washington, D.C., and this is the only clasper shape I have seen 

 from the area. 



The larva of this species is most like that of nephoj^hilus, differing 

 from it in the coloration of the head. In vestitus the dark area does 

 not reach the anterior margin of the head. 



The larvae are found on rocks in streams generally about a meter 

 or two wide, near one or the other end of the pools, generally shunning 

 the fastest water of the rapids and cascades. They construct, in 

 some angle on a rock, a silken shelter of considerable rigidity beneath 

 which they hide. The shelter is open at both ends, but as far as 

 can be seen no trap net is constructed. At pupation time the shelter 

 is strengthened and closed except for a cylindrical aperture at one 

 end. The end of the cylinder inside the shelter is partially closed 

 by a silken sieve. 



