106 College of Forestry 
Cheiropachus sp. 
(Det. by S. A. Rohwer) 
The only reference to a host of a member of this genus 
seems to be that given by Hopkins (1893, p. 148) im which 
he states that C. colon Linn is parasitic upon Seolytus regu- 
losus, the fruit bark beetle. 
We bred our specimens from the limbs of Tree I. The 
parasites emerged in the outdoor cages May 24 and 30, 1916, 
at about the time when the adults of Polygraphus rufipenms 
and Eccoptogaster picee were emerging from the same 
material. The only other insects from this material during 
the summer of 1916 were Phyllobenus dislocatus, Spathius 
tomict and Heterospilus sp., although in the following year 
the typical association characteristics of larch limbs and tops 
emerged. There can be little doubt that this small ptero- 
malid is parasitic upon one or both of the scolytids associated, 
it being nearly certain that HL. picee at least is so affected. 
Prosopis sp. 
(Det. by S. A. Rohwer) 
This small black and yellow bee was bred from an outdoor 
cage containing part of the limbs of Tree I on June 5, 1916. 
Members of this genus of which the habits are known, habit- 
ually breed in the pith of various weeds and pithy shrubs. 
Just what the relations of this small bee was to the larch is 
not known, but had it been only hibernating there, it would 
seem as if it would have appeared in the cage considerably 
earlier than it did. The cage contained no punky wood in 
which it might have bred, but several of the sections of limbs 
did contain the abandoned burrows of C. dentipes and other 
borers, and these borings were filled with closely packed 
frass. It will be readily seen that a burrow in the wood 
packed with frass offers conditions somewhat similar to those 
“in pith, and it seems possible or even probable that the 
specimen taken had actually bred under such conditions. 
Associated insects emerging at about the same time include 
Polygraphus rufipennis, Eccoptogaster picew, Phyllobenus 
