37 



species of Clisiocampa. Many of the trees (or more properl}' bushes, 

 as they seldom, if ever, attain sufficient size to be properly called 

 trees) were killed through repeated defoliation liy the larva? of this 

 insect. A resident farmer stated that the caterpillars were much more 

 numerous some years than others. This beautifully marked larva was 

 first found some 5 miles up Platte Canyon, back of Denver, but 

 occurred there very sparingly. It eats only oak and confines its attacks 

 to young, tender leaves. It seems unable to eat old leaves, and so 

 must mature before they become tough. 



The eggs are laid near the ground on twigs at the base of the trees, 

 and have no frothy covering as have many species of the genus. The 

 larvie are gregarious when young, but soon scatter and feed singly. 

 They spin no web. 



Trypeta galls on Bigelovia. — At the little station of Platte Canj^on, 

 at the mouth of the canyon of that name, there are great numbers of 

 Bigelovia. During the latter part of May every bush ])ears a number 

 of white fluffy but compact galls as big as hazelnuts. Often there 

 will be found 50 or more galls on a single bush. They are caused by 

 a beautiful little fly, Aclara hlgloviai Ckll. At this time of the year 

 the pupoe may be found within the galls, snugly incased in cells at the 

 center. The pupa is about 5""" long by 3'"'" wide, oval in shape, and 

 varying in color from pale yellowish red to brown, probably according 

 to age. The insects emerge bv the first of June, the first ones appear- 

 ing in the breeding cage on May 28. 



The cabbage looker {Plusia hrasslcx Riley). —In the early part of July 

 a few observations were made on injurious insects of the garden in the 

 vicinity of Delta, in Delta County. Several interesting items were 

 noted. The larva of Plnda hrassicse was the main pest, and seemed to 

 be quite omnivorous, eating not only the cabbage, but also the potato, 

 turnip, rutabaga, lettuce, and table and sugar beets; it was also 

 found on a prickly poppy-like plant locall}^ called "wild lettuce." 

 While the cabbage in some cases was almost ruined, it was on the 

 lettuce and potato, especially the lettuce, that the most damage was 

 done. Quite large fields of potatoes were so eaten by this larva as to 

 be easily noticeable at a considerable distance, having something the 

 appearance of being badly infested with the potato beetles. On the 

 lettuce the damage was extreme. In some cases the plant was entirely 

 devoured and was eaten out below the surface of the ground. The 

 rutabagas and peas were also badly eaten. The larvse occurred in 

 various stages, some very small and others full grown. Specimens 

 were sent to Dr. Dyar at Denver to be reared, but they failed to trans- 

 form. An inflated larva was preserved. 



The Cottonwood leaf-heetle {Lma scfripta Fab.). — The willows in the 

 eastern foothills visited by Dr. Dyar and myself were badly infested 

 with a Chrysomelid larva which often occurred in sufficient numbers to 

 completely skeletonize the leaves of large branches. The beetles were 



