Insects Bred from American Larch 55 
of the larger borers, is a more or less casual or incidental 
one, in that the presence of their burrows in the inner bark 
destroys material which would otherwise serve as food for the 
scolytids. The fact that the most usual direction of these 
larger burrows is longitudinal increases the likelihood of 
disaster to the small larvae. On the other hand, the fact 
that the flatheaded and roundheaded larvae are two-year 
forms, is to the advantage of H. picew in that the latter is 
usually associated in the first year of the life of the two-year 
forms, when the larvae of these are small and comparatively 
not so voracious — it being a well-known fact that by far 
the greater per cent of the burrow is made during the latter 
part of a borer’s life history. 
Phyllobenus dislocatus is the only predator found asso- 
cited with H. picew. The parasites associated include 
Spathius tomici, Spathius sp., Spintherus pulchripennis, 
Heterospilus sp., Cheiropachus sp., an undetermined ptero- 
malid, and the fly Medeterus sp. It is impossible to state 
which of these are parasitic upon 17. picew, but a number of 
cocoons were found in the burrows of this scolytid as well as 
in those of P. rufipennis in the same material, but we are 
unable to connect these up with the adults arising from 
them. 
Crypturgus pusillus Gyll. (C. atomus LeConte) 
Crypturgus pusillus is cosmopolitan in its distribution. 
Ratzeburg (1839, pp. 196) recorded it from Germany, Bar- 
bey (1913, pp. 143) has taken it in France, and E. P. Steb- 
bing (1904, pp. 498) has written a short account of its habits 
as he observed them in North and West Himalaya. It has also 
been recorded from Japan by Swaine (1909, pp. 44), and in 
North America Packard (1890, pp. 727) reports the distri- 
bution as extending from Canada to Massachusetts and New 
York. Later literature has extended the range over a con- 
siderable portion of northeastern North America, specifically 
given as Canada and Maine south to West Virginia and 
westward to Ohio (Felt, 1906, pp. 360). 
