1935 ] 
New Nearctic Mecoptera 
113 
uniformly black than the New England specimens, show no 
structural differences whatever. The posterior margin of 
the hypandrium is emarginate, the hypandium as a whole 
being shaped much like that of isolatus, n. sp. (figure 11). 
The body of brumalis is covered with a prominent yellow 
pubescence, which is more striking in the black specimens 
than in the brown ones. 
Boreus nivoriundus Fitch 
Amer. Journ. Agric., 5 : 277 ; 1847. 
This is another species which, previously known only from 
New England and northern New York, has been found in 
Hocking and Fairfield Counties by the above-named collec- 
tors (December 5-25, 1934). The Ohio specimens, like those 
of brumalis , are very much smaller than the more eastern 
ones, being about one-half the length of the latter. In all 
other respects, however, the Ohio specimens and the New 
England ones are identical. The fact that the more southern 
specimens of both brumalis and nivoriundus are decidedly 
smaller than the northern ones suggests that the more mod- 
erate climatic conditions tend to cause smaller specimens in 
this particular genus of insects, which are of course only ac- 
tive in the adult stages from November to February. 
The hypandrium of nivoriundus is entire and shaped very 
much like that of unicolor (figure 15). The color of the 
body is subject to some variation, the New England speci- 
mens being light brown and the Ohio ones somewhat darker, 
but the color never reaches the blackish brown of brumalis. 
Boreus unicolor Hine (Figure 15.) 
Bull. Sci. Lab. Den. Univ., 11:250; 1901. 
This insect has previously been recorded only from Boze- 
man, Montana, and Reno, Nevada (6,600 ft.). In the col- 
lections sent by Dr. Philip and Dr. H. B. Mills there are 15 
specimens of both sexes from Blacktail Flat and Specimen 
Ridge, Yellowstone National Park, Wyoming, March 17, 
1934 and Feb, 5, 1935; and several specimens from Gird’s 
Creek, Ravalli County, Montana, November 2 and December 
30, 1934 (N. L. Jellison). Mr. Lloyd (1934) recorded this 
species from Alaska also, but his specimens really belong to 
a new species ( gracilis ) described below. 
