ted 
tures prevailed during the last week in April, and the control camps 
again closed for a few days by snow conditions. This cold spell was 
of great benefit to the projects, as it not only held back the emerg~ 
ence of the insects so that control work could be completed within the 
_ period planned for, but also relieved the fire hazard of burning the 
infested bark." 

Susceptibility of ponderosa pine to beetle attack.—-Studies by F. i 
P. Keen and W. J. Buckhorn, Portland, Oreg., are reported as follows: i 
"The physical characteristics of ponderosa pine most frequently selected Le 
for attack by the western pine beetle (Dendroctonus brevicomis Lec.) \ 
have been studied on the intensively cruised plots in southern Oregon 
during the past four years. Records taken on more than 27,000 beetle-— 
killed trees as to age and degree of vigor as expressed by sixteen crown 
and age classes, as compared with a similar sample of green unattacked 
trees, shows certain tree classes (defined by combinations of easily ob-— 
served factors influencing vigor, the major factors being age, degree 
of dominance, and crown development) to be decidedly more susceptible 
to attack than other classes. The vigor of the tree as represented by is 
the length and density of the crown apparently is more important than ! 
the age of the tree, although old trees are somewhat more susceptible 
than younger ones. The study also shows that within the tree classes 
recognized by Dunning, and generally adopted in Forest Service marking 
practice, there may be a wide variation in susceptibility to beetle at— 
tack. This is particularly true in the overmature trees of Class 5." 
ee 
Parasites of the larch case bearer.~-D. L. Parker, of the gipsy 
moth laboratory, Melrose Highlands, Mass., reporting on Coleophora lari- 
cella Hbn., says: "Two shipments of parasite material were received during 
the month, both from the same point at Karnten, Austria, totalling 16 
boxes of material containing approximately 60,000 hibernation cases. 
Some of the cases were placed in a cabinet having a temperature of ‘75° 
and a relative humidity of 75 to 80 per cent and from these adults of 
ington for identification. Normal issuance started April 21. and) at» the 
present time 237 males and 205 females have been obtained." C. W. Col- 
lins says, "P. A. Berry has assisted Mr. Parker in caring for the ma- 
terial received from Europe and P. B. Dowden has made dissections in 
an attempt to determine whether the chalcid parasite is acting as a 
primary or a secondary. These dissections, he states, seem to show that 
it is acting as a primary." 
Parasites of Phyllotoma nemorata Fall.—-Reporting on the birch 
leaf-mining sawfly, J. V. Schaffner, jr., of the gipsy moth laboratory, 
says: "The: compilations of our rearings from 1915 to 1929, inclusive, 
show that four of the introduced parasites have been reared from native | 
field-collected larvae." Of these four parasites, Compsilura concinnata 
Meig. was recovered from 108 identified and 6 unidentified hosts; Stur- 
mia scutellata R.D. from 4 identified and 2 unidentified hosts; Apanteles 

