1935 ] 
New Near otic Mecoptera 
115 
of very long, heavy, yellow-brown hairs ; hypandrium emar- 
ginate, the notch broadly “V”-shaped ; rostrum long, more 
than twice as long as the eye. 
Female: length, 4.5-5 mm.; wings, ovipositor and legs 
light brown or yellow-brown ; eyes dark brown or black, pro- 
notum reddish brown ; rest of body black ; entire body cov- 
ered with prominent yellow pilosity, which is especially long 
and deeply colored on abdominal terga; pronotum with the 
two rows of long yellow-brown hairs as in male; ovipositor 
short, only a little longer than the rostrum ; fore wing cov- 
ering hind wing scar. 
Holotype ( $ ) and allotype : Kaslo, British Columbia, 
December, 1932; both in Museum of Comparative Zoology. 
Paratypes : 2 males, 8 females, all with same collecting 
data as holotype in Museum of Comparative Zoology ; and 1 
female from the same lot in the California Academy of Sci- 
ences. 
Boreus isolatus n. sp. (Figure 11.) 
Male : length, 3.2 mm.; wings light brown, eyes brown, 
legs dark brown with the joints black; rest of body black; 
most of body covered with very fine, short, white pilosity, 
uniform over most of body, absent only on the anterior half 
of each abdominal tergum ; hypandrium rather narrow, and 
emarginate, the notch being in the form of a “V” ; rostrum 
short, scarcely longer than the eye. Female unknown. 
Holotype ( $ ) : Como Lake, Ravalli County, Montana, 
January 6, 1935 (W. L. Jellison) ; in Museum of Compara- 
tive Zoology. 
Although somewhat hesitant to describe this species from 
the single male at hand, I believe that the characteristics of 
the male are so distinctive that it unquestionably represents 
an easily recognized species. It is the only one of the west- 
ern species of Boreus which has the combination of the 
emarginate hypandrium and short pilosity, the other species 
with the emarginate hypandrium (pilosus and nix) having 
long pilosity over the entire body, and especially on the ab- 
dominal terga. 
