1947] 
Hydroptilidcz 
175 
and west. Minnesota: Washington Co., May 10, 1941, 1 
male (G. Kretzschmar). Wyoming: Guernsey, N. Platte 
River, Sept. 6, 1946, 1 male (D. G. Denning). 
Hydroptila arctia Ross 
This species has not been recorded since its original 
description in 1938 from Idaho. British Columbia: 
Cowichan Lake, August, 1940, 2 male, 1 female (C. P. 
Idyll). 
Hydroptila acoma n. sp. 
This species can readily be distinguished from other 
members of the genus by the large spur arising from the 
apical portion of the aedeagus. 
Male. — Genitalia as in figs. 2, 2A and 2B. Lateral lobe 
of ninth segment acute, slightly upturned, extended 
caudad about one-half length of claspers. Tenth tergite 
semi-membranous, mesal incision deep, lateral portions 
with apices acute and diverging; seen from lateral aspect, 
fig. 2, distal portion directed dorsad. Claspers slender 
throughout, divergent, apex truncate, beset with short 
scattered setae, between claspers appear two prominent 
caudad directed tubercles. HMeagus with basal portion 
flared, narrowed just before spiral process which encir- 
cles aedeagus one and one-half time, its apex lying along 
side of tube and extending about midway to apex; seen 
from lateral aspect, fig. 2B, a large acute spur arises at 
right angles from apical portion. 
Holotype, male. — Morgan Hill, California, at light, 
August 8, 1941 (Roland Johnson) (specimen with head 
missing). 
Hydroptila valhalla n. sp. 
This species belongs to the perdita Morton group of 
Hydroptila; it can be readily separated from other spe- 
cies of that group by the curious aedagus and the dorsad 
directed mesal portion of the tenth tergite. 
Male. — Length 3 mm. Genitalia as in figs. 3, 3A, 3B, 
3C. Mesal projection of seventh sternite short, apex 
acute. About half of the eighth segment telescoped into 
seventh segment. Claspers slender throughout, fig. 3C, 
