35 



that the mites easily got too much moisture, and in this direction 

 observations should be continued to find out whether it be possible to 

 find a degree of moisture which will either kill or drive away the 

 mites without being detrimental to the growth of the mycelium. 



NOTES ON COLORADO INSECTS. 



By A. N. Caudell. 



Acting under authorization from the Department of Agriculture, I 

 arrived at Denver, Colo., May 6, 1901, where I was joined by Dr. H. G. 

 Dyar. With Denver as headquarters, daily excursions were made 

 into the canyons and foothills of the mountains, and the life histories 

 of many western Lepidoptera were worked out, notes being taken on 

 more than 200 species. In the months of July and August trips were 

 made across the divide to various localities, adding materiall}' to our 

 collections. According to instructions, I "collected such economic 

 and other insects as came convenient and made observ^ations on eco- 

 nomic species whenever possible." M}' first duty of assisting Dr. D3'ar 

 in working out Lepidopterous life histories prohibited my making 

 large collections in other orders. Some 5,000 specimens of Orthop- 

 tera, however, were collected, together with some hundreds of miscel- 

 laneous insects, mostly Coleoptera, of which a few were reared. Such 

 observations on economic insects as I was able to make are here 

 reported. 



The minute false chinch hug {Nysius m,inutus Uhl.). — At Delta 

 occurred an extreme case of injury to radish by this insect. The 

 leaves were completely killed to the ground, and the shriveled remains 

 were still covered by many hundreds of the little pests, Mr. O. 

 Heidemann identified the species. 



The heet army inorm, {Laphygma exigua Hbn.). — This has become an 

 important enemy of the sugar-beet industry in the West. Specimens 

 of the larva in all stages were taken on sugar beets at Palisades in 

 Mesa County, and at Delta. At the latter place they were taken also 

 on the table beet, though they did not occur in injurious numbers. 

 This insect is reported as having caused great injury to sugar beets 

 in Colorado, defoliating thousands of acres of beets. It is also said 

 to be injurious to potato, pea, and apple leaves. Professor Gillette, 

 of the Colorado experiment station, has employed arsenical sprays 

 against it with beneficial results. Professor Forbes concludes from 

 data furnished by Professor Gillette that there may be expected at 

 least two broods of larvfe each year — one in June and one in August. 

 But the broods doubtless merge one into the other, as larvae in all 

 stages were taken at Palisades on July 8. 



The hean ladyhird {Epilachna corrupta Muls.). — An extreme case 



