Insects Bred from American Larch 91 
senior author observed three specimens at one time hovering 
about spruce recently felled and stripped for pulp wood and 
which was at that time being piled upon a skidway. 
Entomological literature contains numerous mention of 
this insect as a wood borer, but apparently no data is avail- 
able as regards length of larval and pupal life history. Our 
data, while not absolutely conclusive, shows that usually the 
life history is completed in one year. This, however, is 
doubtless subject to considerable variation, dependent not 
only upon the general climatic conditions but also upon the 
exact individual conditions in each case. 
The eggs are deposited by the females in the bark of 
dying or recently felled coniferous trees. Preference is 
shown for recently felled trees, but failing these, trees dying 
or even dead are used for ovipositing. The larvee on hatch- 
ing bore directly into the wood, in which they construct their 
mines throughout their entire larval existence. These bur- 
rows run in all directions through the wood and are closely 
packed with a very fine dust like frass. In general they are 
very much like the mines of S. barbatus, but can be dis- 
tinguished by the fact that they are nearly exactly circular in 
eross section, while those made by the melandryid are oval. 
Adults of this siricid emerged in our outdoor breeding 
cages during June and July. In all, twelve specimens were 
obtained — comprising two females and ten males. Of 
these one male and one female were obtained in July, 1916, 
from Tree IJ. The other female and the nine males were 
obtained from the lower, middle and upper trunk regions of 
Tree X. Mr. Rohwer of the Bureau of Entomology in iden- 
tifying these specimens makes the following statement 
regarding the males: “At present there are no characters 
known which definitely separate the male of Urocerus albt- 
cornis Fabr. from the male of Urocerus flavicornis Fabr. 
and it is impossible to be positive as to the above determina- 
tion.” However, the fact that the males were bred from the 
same material as the known females of U. albicornis and 
emerged at about the same time would make the presumption 
very strong that they belong to this species. These specimens 
