122 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



adults emerge the following spring about the time the larch foliage 

 appears. 



The larch sawfly (Pristiphora erichsonii (Hartig)), a native of 

 Europe and first found in New England about 1880, has spread 

 westward through the Lake States and Canada into northern 

 British Columbia. Its progress has been disastrous, inasmuch as 

 it kills trees rapidly, and has left vast areas of dead and dying 

 larch in its wake. It was first noted attacking western larch in 

 southern British Columbia in 1930 and since has been found in the 

 northwestern part of the United States. 



The cypress sawfly (Susana cupressi Ron. & Midd.) feeds on 

 the foliage of Monterey cypress in California. 



SAWFLIES ON BROADLEAVED TREES 



The elm sawfly (Cimbex americana Leach) is commonly found 

 in the Middle West, as well as in the Eastern States, but ranges 

 west into Colorado and British Columbia. These sawflies are 

 active feeders on the leaves of willow and elm, and also attack 

 poplar, alder, maple, and other trees. The adults are large, steel 

 blue to black, broadwaisted sawflies about 3 4 inch long with three 

 or four yellow, oval spots on each side of the body, with short 

 knobbed antennae, and smoky wings. They girdle the bark on 

 twigs and kill many of them, especially in the tops of trees. The 

 larvae are naked, wrinkled, and pale yellowish with a median 

 black stripe down the back, and have eight pairs of prolegs. They 

 usually lie coiled and are from 1 to 2 inches long when full grown. 

 The adults fly in May and insert their oval eggs in the leaves. The 

 larvae reach full growth in July or August, and overwinter in 

 cocoons in the debris on the ground or just below the surface. 

 Pupation occurs in the spring, only a few days before emergence 

 and flight. 



At least three other species of sawflies attack willow in the 

 West. Cimbex pacifica Cress., which has habits similar to ameri- 

 cana, is found in Oregon and Washington. Cimbex rubida Cress, 

 is found in California and Nevada, and Trichiosoma lonuginosa 

 Nort. is also found in the California and Nevada Sierras. 



The cottonwood sawfly (Pteronidea sp.), although common, has 

 not yet been identified specifically. The larvae, which are slender, 

 about y 2 inch long, green, with brown head and black eyes, and 

 six pairs of prolegs on the abdomen, feed on the leaves of black 

 cottonwood in northern Idaho. 



LEAF BEETLES 



There are a number of beetles that are leaf eaters in the larval 

 or adult stage or in both. None of these have been responsible for 

 any serious injury to western coniferous forest trees, but the 

 skeletonizing and defoliation of broadleaved trees by beetles is 

 common. Most of these beetles belong to the family Chrysomelidae. 

 The adults of this large family of destructive beetles are small, 

 rather short, somewhat oval in outline, and of variegated colors, 

 some with bright metallic green or blue and others dull brown or 



