72 NATURAL HISTORY 



them when there seems to be the greatest 

 occasion. The males only make that shrill- 

 ing noise perhaps out of rivalry and emu- 

 lation, as is the case with many animals 

 which exert some sprightly note during 

 their breeding time : it is raised by a brisk 

 friction of one wing against the other. 

 They are solitary beings, living singly male 

 or female, each as it may happen ; but 

 there must be a time when the sexes have 

 some intercourse, and then the wings may 

 be useful perhaps during the hours of night. 

 When the males meet they will fight fierce- 

 ly, as I found by some which I put into 

 the crevices of a dry stone wall, where I 

 should have been glad to have made them 

 settle. For though they seemed distressed 

 by being taken out of their knowledge, 

 yet the first that got possession of the 

 chinks would seize on any that were ob- 

 truded upon them with a vast row of ser- 

 rated fangs. With their strong jaws, 

 toothed like the shears of a lobster's claws, 

 they perforate and round their curious 

 regular cells, having no fore-claws to dig, 



