258 THE BUTTERFLY VIVARIUM. 



the earth hy spontaneous generation. Their Latin 

 name, Pulex, too, is said to he derived from pulvis, 

 dust, which shows that a similar popular idea 

 was prevalent in Italy as well as Greece. Even in 

 modern times, the learned Scaligcr thought they 

 were produced spontaneously from the humous 

 matter ahout the roots of the hair of dogs. The 

 female lays ahout twelve eggs, Avhich become, when 

 hatched, small, slender, worm-like larvae. These 

 enter into the usual pupa state, and at last the 

 perfect Flea appears. 



13. The order Diptera contains, as the name 

 implies, those insects which have only two wings 

 instead of four. As well-known examples, the tribe 

 of Common House-flies may be cited. Among the 

 Forest-flies, known as the Ilvppoboscklee, the egg 

 passes to the larva and pupa state before it is laid, 

 and is eventually deposited by the parent in the 

 form of a small oval chrysalis, from which curious 

 aberration it might have been inferred that this 

 insect did not, like all others, pass through the usual 

 stages of development, but was hatched from the 

 egg in its perfect form, like a chicken. The term 

 JDiptera is one of those highly characteristic dis- 

 tinctive names invented by Aristotle, which is likely, 

 as in the case of his picturesque term Coleoptera, 



