1974] 
Cooper — Bore us 
113 
(196) holds Boreus to be acceptable to small birds as welcome sup- 
plement to their winter fare, and that Boreus ’ escape leap and thano- 
taxis perhaps offer it some protection against predation. No one seems 
to have observed birds feeding on Boreus, however, and McAtee’s 
extensive analysis of the stomach contents of birds provides no records. 
Lestage (1940), on the other hand, cites a unique record of the 
remains of Boreus from the stomachs of trout, even adding “[les] 
Truites ont montre celles-ci friandes des Boreus”! Other possible 
predators that have been mentioned are spiders, often abundant on 
snow during warmer days, and rapacious insects (Vlasov 1950, Greve 
1966) — but none have been shown to be such. Definite information, 
however, can be given on actual and probable parasites of species of 
Boreus. 
In my own experience, I have but once found mites on Boreus. 
Four adult individuals of a species of Pediculaster (Pyemotidae; 
determined by Prof. Earle A. Cross) were in neat parallel array, 
lengthwise to abdominal sternites-i and 2, nearly concealed between 
the abdomen and the dorsal faces of the metacoxae, on which they 
were seated, of an adult male of B. brumalis (Hanover, N. H., 
Jan. 8, 1961, air temp. i.7°C). The record is of special interest for 
it is a likely, occasional parasite of Boreus. Insofar as the habits of 
species of Pediculaster are known, they are ordinarily phoretic on a 
number of diverse flies, and Vitzthum found that P. mesembrinae 
(Canestrini) drop off their hosts at oviposition sites, attacking there 
the developing fly larvae (see Cross 1965). 
A not surprising second parasite of Boreus is a Cor dy ceps (Sphae- 
riales, Clavicipitaceae) that in one case of 5 such emerged from the 
intersection of the frontal and coronal sutures, as well as from be- 
tween the 9th and 10th abdominal tergites of a mummified 4th instar 
larva of B. brumalis found erect in its vertical burrow just beneath 
the basal stems of the host moss, Dicranella heteromalla (Hedw.) 
Schimp. (Princeton, N.J., Nov. 19, 1939). The portion of the 
fungus from the head bifurcated into two fruiting bodies (each about 
3-4 mm long), extending vertically upwards and nearly parallel. 
The limb from the abdomen bent sharply and vertically upwards, 
and was nearly 5 mm long. In all, the 5 Cordyceps-iniected larvae 
were among 25 + larvae collected that day from one large turf of 
the moss growing at the base of a tulip tree. Of 35 pupae collected 
at the same site and time, none were afflicted by the fungus. 
The only parasites that have been recorded from B. hyemalis are 
hymenopterous. The braconid Dyscoletes lancifer Haliday was shown 
