176 
Psyche 
[Sept. 
divergent, apex acute, darkened and directed laterad, 
base hidden in ninth segment, which in turn is withdrawn 
into eighth and seventh segments. Tenth tergite entire, 
semi-membranous, extending caudad beyond any other 
portion of genitalia; lateral margins somewhat more 
heavily sclerotized than remainder; mesal lobe sub-tri- 
angular when viewed from dorsal aspect, tig. 3. MMea- 
gus long and slender, basal portion nearly straight, nar- 
rowed toward center then suddenly widened, apparently 
forms a distinct division from apical portion which is 
bulbular at base then constricted to an acute apex, entire 
apical portion turned laterad when viewed dorsally, 
turned ventrad when viewed from lateral aspect. 
Holotype male. — Taylors Falls, Minn., August 1937 
(C. J. Palmer). 
Mayatrichia ayama Mosely 
The available distributional records of Ross indicate 
this species is widespread; the Minnesota record is an 
extension in the known northern limits of its range. 
Minnesota: Washington Co., May 10, 1941, 1 male (Gr. 
Kretzschmar). 
Explanation of Plate 15 
Fig. 1. Oxyethira obtatus, male genitalia, lateral aspect; 1A, apex of 
eedeagus ; IB, ventral aspect of male genitalia , 
Fig. 2. Hydroptila acoma, male genitalia, lateral aspect; 2A, ventral aspect 
of male genitalia ; 2B, sedeagus. 
Fig. 3. Hydroptila valhalla, male genitalia, dorsal aspect; 3A, seleagus; 
3B, lateral aspect of male genitalia ; 3C, clasper. 
