mes 
This may be due to an actual difference in the Sex ratio when adults ma- 
ture or may be due to the fact that the females live longer than the 
males. This is not true in the fall generation, which normally runs be— 
tween 60 percent and 65 percent males." 
FOREST INSECTS 
Solar heat effective control for western pine beetle.~-J.M. Mil— 
ler, Berkeley, Calif., reports that "A summer control program against 
the western pine beetle (Dendroctonus brevicomis Lec.) is now under way 
on the Bass Lake Unit of the Sierra National Forest. A crew of about 
25 men from Sugar Pine Camp (F-90) have been assigned to treat Summer 
brood trees by the solar heat method. Up to July 31, 275 trees, with 
a total volume of 243,190 board feet, had been treated. It was found 
that field temperatures during July were highly effective in producing 
100 percent mortality whenever the bark received even brief exposures 
to the sun at midday." 
Elm leaf beetle gains footing in Yosemite Park.-—-Mr. Miller also 
states that "Elm trees (Ulmus americana) were planted in the valley 
floor of Yosemite at the time of early settlement, probably about 1880. 
These planted trees now compose part of the parking in the old Yosemite 
Village. In 1932 these elms were defoliated by Galerucella xanthomelaena 
Schr., and during the summer of 1953 the beetle has been so abundant as 
to defoliate completely all planted elm trees in the Park. Just how the 
elm beetle reached this locality is a question, but very probably it was 
carried in by auto campers. The elms are isolated by many miles of moun— 
tainous country from the localities where this beetle occurs in the San 
Joaquin Valley, and the possibility of its flight into Yosemite is a re-— 
mote one." 
Clean-up of Crater Lake National Park forests effective in con— 
irolling pine beetle.—-Reporting on cooperative control work, F. P. Keen, 
Portland, Oreg., says: "Using nearly the entire force of the 400 Civilian 
Conservation Corps workers assigned to Crater Lake National Park, an ex— 
haustive beetle clean-up campaign was conducted over the 30,000 acres 
comprising the susceptible pine areas of the Park. The work was completed 
Shortly after the end of the month, at which time the more advanced 
broods of the mountain pine beetle (Dendroctonus monticolae Hopk.) had 
just reached the new adult stage. Last year 20,311 infested pines were 
treated on this area. This year a diligent combing of the area by 4 
Spotting crews resulted in finding only 6,161 infested pines, a reduction 
of 70 percent. In fact the Park forests are now so free from mountain 
pine beetle infestation that a 2-day inspection of the treated areas 
failed to reveal a single living beetle." 
More on winter mortality of mountain pine beetle.--A, L. Gibson, 
Coeur d'Alene, Idaho, reports that in June he "found that an exceedingly 
heavy winter mortality had occurred in the broods of the mountain pine 
beetle in the Beaverhead National Forest. In July Mr. Gibson extended 
his examinations to include an additional number of areas both on and 
