An Insect Virus 



ner of life subjects him to prolonged contact 

 with his own ordure. 



Now consider the Hedgehog Caterpillar. 

 Why is he harmless, despite his fierce and 

 hirsute aspect? Because he lives in isolation 

 and is always on the move. His mane, apt 

 though it be to collect and retain irritant part- 

 icles, will never give us the itch, for the 

 simple reason that the caterpillar does not lie 

 on his excretions. Distributed all over the 

 fields and far from numerous, owing to the 

 caterpillar's solitary habits, the droppings, 

 though poisonous, cannot transfer their pro- 

 perties to a fleece which does not come into 

 contact with them. If the Hedgehog lived 

 in a community, in a nest serving as a cess- 

 pit, he would be the foremost of our stinging 

 caterpillars. 



At first sight, the barrack-tooms of the 

 Silkworm-nurseries seem to fulfil the condi- 

 tions necessary to the surface venom of the 

 worms. Each change of litter results in the 

 removal of basketfuls of droppings from the 

 trays. Over this heaped-up ordure the Silk- 

 worms swarm. How is it that they do not 

 acquire the poisonous properties of their own 

 excrement ? 



175 



