70 COLORADO POTATO-BEETLE. 



If these insects are knocked off the vines in the middle of a very 

 hot and dry day, the mercury in the thermometer ranging at 95o 

 or upward, they will die in about one minute, as I have tested by 

 actual experiment. The soft-bodied larvae roll over and over and 

 seem to almost liquify from the heat. The beetles spread their 

 wings and attempt to escape, but cannot rise from the broiling 

 e\irface. Two of my fellow travelers on the ad interim Commit- 

 tee, Mr. Galusha and Mr. Wier, both certify, from their own expe- 

 rience, to the efficacy of this method when the conditions are 

 favorable. The former adds that it is most effective where the 

 potatoes have been hilled up, so as to present an inclined plane of 

 crumbling earth, up which the insects must climb, under the 

 fierce fire of the enemy, before they can reach the protecting 

 shelter of the over-spreading foliage. The objection to the prac- 

 tice of this plan is that the operator has to expose himself to the 

 same heat which is fatal to the insects, and besides, there are usu- 

 ally but few days in the year when this remedy is available. 



Another agency for lessening the numbers of the Potato-beetle 

 is starvation. This takes place from the simple fact that the in- 

 sects, in some cases, eat all the potatoes and other available food 

 within their reach, whilst many of them are immature, and before 

 the season is far enough advanced for them to go into winter quar- 

 ters. I have been forcibly struck the present season with the ef- 

 ficacy of this condition of things in my own neighborhood, and 

 it must have occurred in many other localities. I have seen my- 

 riads of these insects, in all their stages, leaving the potato-fields, 

 wliere they had left scarcely a stump standing, and traveling over 

 fences, buildings and roads, and I may say everywhere, but where 

 there was no congenial plant food within their reach. The per- 

 fect insect, it is true, can fiy to a considerable distance, but the 

 supply of food sometimes gives out when the great majority of the 

 insects are in their larva state. I have heard of their being seen 

 crawling half a mile or more from any place where potatoes grew : 

 this, however, I think must have referred to the mature beetles, 

 which had availed themselves of their wings for a part of the dis- 

 tance. An important question arises in such cases, whether these 

 insects are capable of subsisting upon other plants besides the po- 

 tato, to a suificient extent to preserve them from starvation. It is 



