INSECTS AND WAR 23 



Mr. Butler recalls the case of a gentleman who 

 collected on four successive mornings sixty-two, 

 seventy-eight, sixty-seven, and seventy-seven cat- 

 fleas' eggs from the cloth his cat had slept upon, 

 altogether 284 eggs in four nights. 



The date of hatching varies very much with 

 the temperature. Pulex initans takes half as 

 long again six weeks instead of four to become 

 an adult imago in winter as it does in summer. 

 But in India the dog-flea will complete its cycle 

 in a fortnight. 



When it does emerge from the egg the larva 

 is seen to be a whitish segmented little grub 

 without any limbs, but with plenty of bristles 

 which help it to move about and this it does very 

 actively. There are two small antennae and a 

 pair of powerful jaws, for the larva does not 

 take liquid food, but eats any scraps of solid 

 organic matter which it comes across ; dead 

 flies and gnats are readily devoured. The larva 

 casts its skin several times, though exactly how 

 often it moults seems still uncertain. 



After about twelve days of larval existence it 

 spins itself a little cocoon in some sheltered 

 crevice, and turns into a whitish inert chrysalis 

 or pupa. During its pupal existence it takes, 



