1974] 
Cooper — Borens 
85 
bears upon the tenability of the order Neomecoptera that specially 
sets Boreus apart from other scorpion flies; the likelihood that Boreus, 
like other Mecoptera, has four larval instars; the occurrence of both 
pupal and adult pharate stages in development; that whatever limits 
the distribution of a species of Boreus , it is not its host mosses; and 
finally, that Boreus species, despite their peculiar life cycle, may have 
an obligate hymenopterous parasite, a matter which puzzled Withy- 
combe. The third and final article will deal with the range of habi- 
tats species of Boreus have entered, the mosses with which Boreus 
species are associated, interpretation of Boreus as a winter insect, 
and a reconsideration of its distribution in relation to drift and glaci- 
ation. 
Occurrence and Span of Adult Activity 
Boreus notoper ates has so far been collected at two localities only, 
both being NW faces of steep canyons, at 1219m altitude (Cold- 
water Canyon) and at 1645m (Black Canyon), on Mt. San Jacinto, 
Riverside Co., California. The first is a yellow pine — chaparral 
ecotone ( Pinus ponderosa Dougl. — A denostoma fasciculatum Hook, 
and Arn.) that is Upper Sonoran, or Upper Austral in Merriam’s 
( 1898) original sense, the mean temperature for the six hottest weeks 
(July through mid-August) being — 24°C. The second is a mixed 
woods of yellow pine, incense cedar, white fir and canyon oak ( Pinus 
ponderosa , Libocedrus decurrens Torr., Abies concolor Gord. & 
Glend., and Quercus chrysolepis Liebm.), fringed and penetrated by 
chaparral elements; it is Transitional, the corresponding high mean 
temperature being about 2i°C. Over the period 1955 — 71 the mean 
annual precipitation (close by at the Idyllwild Fire Station, alt. 
1645m) was 59.6 cm (23 in.), with 74% falling in the months of 
November through March during which adult B. notoperates have 
been collected. The adults have so far been found only on mosses 
growing on boulders and large jointed blocks of diorite, or on snow 
about them, in both fairly open (chiefly Coldwater Canyon) and 
shaded (chiefly Black Canyon) situations. Even during the period 
of winter precipitation the mosses are only periodically dampened 
and luxuriant, for precipitation is widely scattered, and melts rapidly 
when snow. The activity of Boreus at all its stages coincides with 
those periods, frequently brief and generally spaced out, when the 
mosses and their roots are damp. At other times the relative humidity 
is low, the mosses are dry to the touch, even friable, and their sods 
