FRISCH 243 



writings, like those of nearly all foreign naturalists, 

 were unknown to White. 



Hydrophilus ^ 



Friscli tells us that he had not meant to study 

 aquatic insects, but that they drew him insensibly to 

 the water, and even into it. The large size of Hydro- 

 philus no doubt attracted his attention, and he kept the 

 beetles long in captivity for the purpose of studying 

 their mode of life. Throughout the autumn and winter 

 they lived happily (in some kind of aquarium, I 

 suppose), but when spring came round they strove to 

 leave the water, and died if prevented from doing so. 

 Frisch recognised the larva and pupa, but never found 

 the egg- cocoon. He noticed the arched attitude which 

 the pupa takes when resting in its underground cell, as 

 well as the spines which keep it from touching the 

 ground, and demonstrated in the adult beetle the 

 presence of an air-space beneath the elytra, into which 

 the spiracles open. When he removed one of the elytra 

 a rhythmical pulsation of the air beneath the folded 

 wing was clearly seen.^ 



Ger^man Cochineal^ 



German cochineal is the product of a scale-insect 

 [Porphyroj^hora polonica), which makes galls on the 

 roots of Polygonum cocciferum. Frisch describes the 

 galls, the gall-forming insect, and the cottony threads 

 which issue from its back. His figures are so minute 

 and so rude that they are barely recognisable. He 

 quotes ancient monastic writings to prove that the 

 scarlet dye yielded by this insect was once largely used 



* Pt. II, ch. vii, viii. 



2 The pulsation can l>e observed without injuring the beetle. 



^Pt. V, oh. ii. 



