BRITISH INSECTS 



even if possessed of most obnoxious habits. It even 

 excited the attention of one of the world's greatest men, 

 Socrates, who stopped to enquire how far it could jump. 

 As a matter of fact, we are told it can jump four inches 

 into the air and about a foot on the level. As Prof. 

 Thomson says : " It is quite far enough." Pulex irritans 

 is found tenanting the wil}' old Badger, as well as human- 

 kind, the eggs being laid among the animal's fur, or 

 in dusty cracks and crevices of houses. The active 

 larva — a small legless grub which moves by the aid of 

 bristles — lives on organic matter, and after twice casting 

 its skin, the pupal state is reached. In due course the 

 perfect Flea is ready to emerge from the cocoon-envelope, 

 but it often waits until someone, or something, " pulls 

 the trigger of activity," and thus releases it. Minus 

 wings, the Flea must certainly be regarded as a bit of a 

 masterpiece, and its " muscular explosiveness verges 

 on the miraculous." Nevertheless, it is a great nuisance 

 and a serious pest, for, between 1896 and 191 1, upwards 

 of seven million people died in India from Bubonic 

 Plague, mainly through the bite of a Rat-Flea {Xeno- 

 psylla cheopsis) which transfers the virulent microbe 

 from rat to rat, and from rat to man. Flea-control 

 and Rat-control are essential, especially in our ports, 

 harbours, congested cities, and other places. But we 

 must not be tempted to pursue the subject further, 

 and a mere list of names and usual hosts would occupy 

 more space than we have at disposal. 



The Cecidomyiidcs consist of a family of very small 

 78 



