78 



to do much harm outside of a small reg-ion situated near the foothills 

 along the eastern slope of the Rockies in the northern half of Colorado. 

 In this region, during the past ten years, they have been very serious 

 pests. C. sern.iferana confines its attacks in the region mentioned 

 entirel}' to the box-elder, while C. argyrosjnla is a very general feeder, 

 being able to subsist upon the foliage of almost any deciduous tree or 

 shrub. I have seen small orchards entirely defoliated by this species 

 so that not a green leaf could be seen, and the box-elder species has 

 been equally destructive to the foliage of that tree. At present these 

 insects have nearly disappeared in Larimer County, ])ut they are still 

 very destructive in the vicinity of Denver and Boulder. 



The case seems to be one where two closely-related insects reached, 

 at about the same time, a region where their food-plants were abund- 

 ant and their enemies scarce. As they have risen and fallen together 

 in numbers, it seems probable that they are controlled in a state of 

 nature by the same checks. We have bred not less than ten species of 

 parasites from them. 



The habit of the female of C '. semiferana in shingling her egg patches 

 with the large flat scales from the underside of her abdomen is unique 

 among insects so far as the writer is aware. Does anyone present 

 know of a similar habit in another species ? 



The peach-twig borer, Aiimma lineateUa, has become a serious 

 enemy in peach orchards on the western slope within the State. It 

 has done much injury this year in pruning back the new growth on 

 young trees, and promises to occasion a heav}' loss of fruit a little 

 later as the first brood has matured in large numbers. The most 

 promising remedy so far seems to lie in the use of bands upon the 

 trunks of the trees for capture of the larvae, as in case of the codling 

 moth. 



The peach borer, Sannina exitiosa^ is present in the peach-growing 

 sections, but for some reason does not do serious harm as yet. 



The currant borer, Sesia tijynliforinis^ is as abundant in the north- 

 ern portion of the State as I have ever known it anywhere. 



The woolly plant louse, Schhoiieura lanigera^ probably ranks next 

 to the codling moth in importance as a pest in apple orchards in the 

 State, and is particularly abundant on the west slope. Tobacco dust 

 is taking the lead as a remedy for the root form. The number of 

 trees actualh' killed by this insect in the State have been quite small. 



The pear and cherry tree slug, Erlocampoides Ihnachia, is very 

 destructive, particularly to pear foliage, wherever remedies are not 

 promptly applied for its destruction. It is worst at present on the 

 western slope. 



The San Jose scale is as yet unknown within the State. The only 

 member of the family Coccidte that has attracted any special attention 

 is Aspidiotus ancylus, which I have seen rather abundant on several 



