38 



reared, and were determined by Mr. Schwarz. The egg's are deposited 

 on the leaves al)Out the middle of May, and are continually deposited 

 for two or three weeks thereafter, all stages — ovum, larva, pupa, and 

 imago— being found on the trees in the earlier part of June. They 

 remain in the pupa state about live days, specimens in the ])reeding 

 cage pupating on June 1, and giving forth imagos on the Gth. The 

 larval period lasts but a couple of weeks, and breeding experiments 

 would probably show the insect to be at least double- brooded. 



Tlie hollworm, or corn ear-irorm {Hellotkis arnviger Hbn.). — Young 

 corn a couple of feet in height near Delta was badly infested with the 

 bollworm. The leaves were in some cases completeh" riddled near 

 the base, and the stalks badl}^ burrowed and eaten. This exceptional 

 injury was probably accounted for by the nearness of the worst 

 infested patch (a small area) to an irrigating ditch of considerable 

 size. Corn in dryer locations seemed little injured. Corn on low 

 wet soil is usually nuich more liable to excessive injury from the corn 

 worm than on high dry ground. Some years ago in Oklahoma I saw 

 a small area of field corn planted in a ver}" low wet spot in the bend of 

 a small creek that was completely eaten up by the worms. The stalks 

 attained a height of only about -A feet and were very weak and 

 slender, yet 20 or more larva? could be found in a single plant, bur- 

 rowing the stalks so that many fell over. Some plants had all the 

 leaves riddled and the stalk so completelly eaten out that but part of 

 the outer shell remained. So numerous were the larvae that many of 

 them were in a fully exposed position, feeding upon the leaves. 



Grasshoppers. — Grasshoppers were very abundant in Colorado this 

 year. Several reasons ma}" be assigned for their imusal numbers. 

 The season was favorable for their development, and the increasing 

 abundance all over the State of the Russian thistle, which is a food 

 plant of a large number of species, may have had considerable influence 

 in the matter. Professor Bruner suggested also that the rapid killing 

 off of pheasants ma}" l)e a cause of grasshopper increase. 



The prairie along the eastern foothills was swarming with various 

 kinds of Acridiinaj. Melanoplus hivlttatus was probably the most 

 coimnon species. At Delta this locust threatened to do some damage, 

 and it occurred sparingly at Grand Junction, while at Palisades, 12 

 miles north, none at all were seen. This is a very injurious species, 

 and Professor Gillette places it on an equal footing with the codling 

 moth as an injurious insect. 



The saltbushes, Sarcobates vermicular Is, about Palisades were 

 infested with ^olophis chetiopodli Brun. in large numbers. A small 

 patch in the center of the little town was swarming with them. They 

 were quite active, diving headlong into the prickly bunches of weeds, 

 and proved quite difficult to cai)ture. They were not at all common 

 at Grand Junction, and were not taken on the saltbush there. 



