Hi 



As far l)ack as 1742, Kraininii', in liis famous "Momoii-cs 

 pour sei'vir a I'liistoire iiaturellc dcs insect es," described 

 experiments whicli confirmed tlic i)opular opinion that 

 insect larvae can be frozen ]ia)-(l willioul Ix'ini;- killed. He 

 froze caterpillars at -8.8° and icNixcd llieni. It is of in- 

 terest to notice that the method wliicli was nsed by most 

 of the investigators of low temperatnre effects and which 

 consists in putting the organisms into a glass tube and 

 immersing the latter into a mixture of ice and salt, was 

 tlie one used by this pioneer two centuries ago. Kf'aumnr 

 was ])ro])al)ly also tlie tirst to remark that some juices, in 

 the caterpillars, do not freeze at the freezing point of most 

 of the body lluids, he thought that they must congeal at 

 a lower temperature wiiich would be the death point. This 

 idea has been developed and studied experimentally dur- 

 ing the last 30 years. 



From the middle of the eighteenth to the end of the 

 nineteenth century, the revival of hard frozen insects and 

 mostly of larvae has been asserted by a legion of natural- 

 ists. From a review of the literature of that period one 

 gains the impression that it was the most generally ac- 

 cepted view. However, there were divergent statements. 

 To explain the differences reported, one generally had 

 recourse to specificity. In the review lists we find silk- 

 worms, chrysalids, caterpillars, grasshoppers, mosquitoes, 

 bedbugs, scolopendrae, etc., among the animals reported 

 to have survived hard freezing, while ants, aphides, bnt- 

 tertiies, house flies, and particularly bees are perhaps 

 more often quoted among the sensitive insects. Bees 

 have been reported by many to die at a temperature of a 

 few degrees above zero (cf. Bakhmetieff, 1901). But 

 what role is played in cold resistance by specificity or by 

 the stage of development, the age, the season, adaptation, 

 and by other similar factors, has by no means been eluci- 

 dated in older works. The improved methods and the 

 more systematic studies of the last 50 years or so have 

 l)rought some light on the action of a few of the above- 

 mentioned factors. 



