THE CANADIAN ENTOMOLOGIST. 37 



In the active state the species mentioned are readily drowned. In 

 some experiments made to determine this point I found that few survived 

 submersion in water for half an hour, and none for over an hour. 



The degree of cold that can be endured without death is probably 

 variable according to the species, the more tender retiring on the approach 

 of cold weather deep into the earth, or into substances that are poor con- 

 ductors of heat, as leaves, moss and decaying wood. Others that can 

 sustain low temperatures without injury seem rather indifferent about the 

 matter, crawling under any covering that happens to be convenient. 



Some of the European entomologists by experiments seem to have 

 satisfied themselves that the larvae of some Lepidoptera may be congealed 

 into masses of ice and fractured as readily as glass, and yet revive and 

 regain their full activity. Though hard to beHeve, the statement is as 

 worthy of credence as any that depends on human testimony. However, 

 all the observations I have made on Coleoptera and their larvae go to show 

 the contrary, having never succeeded in reviving any in which there was 

 absolute certainty of the tissues being frozen. 



The larvs of Urographis fasciatus and Dendroides Catiadensis, which 

 live within or just beneath the bark of fallen timber, were examined 

 recently with reference to determining this question. They were found in 

 their shallow excavations, the most of them surrounded by glittering cry- 

 stals of ice. Nearly all were flexible and the tissues unfrozen, and mostly 

 revived. A few were frozen solid and broke readily, none of these giving 

 evidence of life. . 



A large number of the larvae of Dedes spinosiis, inhabiting the stems 

 of Ambrosia arternisifolia (rag-weed) at or just below the surface of the 

 ground, were taken out of their quarters. In many instances the stems 

 had been filled with water and the larvae were enclosed in cylinders of 

 ice. The greater number were flexible and mostly regained activity on a 

 rise of temperature ; such, however, as were evidently congealed could 

 not be resuscitated. 



In the torpid condition some species of Coleoptera certainly have the 

 power of sustaining vitality while exposed for a long time to a temperature 

 below, or but little above the o of Fahr. The first week of this month 

 (February) I found a large collection of Megilla macidata in a field, near 

 a tree ; they had congregated on the ground under and around a small 

 piece of shingle that did not cover the half of them, and were massed 

 together on top of one another to a considerable depth — all apparently 



