BOOK XI. XL. ii6-.\Lii. 119 



as it is the only animal that has no vent for its food : 

 with gorging to exeess it biirsts, so dying of its very 

 nutriment. This creature never grows in cart- 

 horses but occurs frequently in oxen and occasionally 

 in dogs,* in which all creatures breed, whei-eas this 

 alone occurs in sheep and goats. Equally remarkable 

 is the thirst for blood that is even felt by leeches in 

 marshy water ; for they too penetrate with the whole 

 of their head. Dogs have a special pest of their 

 own, a maggot that lances particularly their ears, 

 which they cannot protect by their bite. 



XLI. Similarly, dust in woollens and in clotlies ciotkes- 

 breeds moths, especially if a spider is shut up with ZlfieL^"'"''^' 

 them ; for being thii-sty and sucking up all the 

 moisture it increases the dryness. This is also 

 noticed in papers. There is a kind of moths that 

 carry their own coats in the same way as snails ; 

 but the moths have visible feet. If stripped of their 

 coats they die, but if they gTOw up, they form a 

 chrysahs. The wild fig-tree breeds fig-gnats ; 

 beetles are produced by the maggots of figs and of 

 the pear tree, pine, dog-rose and rose. This 

 poisonous creature brings its remedies with it — 

 the wings have a healing power ; but with these 

 removed it is deadly. Again, other kinds, namely 

 gnats, are bred by a substance growing sour, and in 

 fact Avhite ones are found even in snow, and also in 

 snow that has been lying for some time maggots, 

 which in a moderate depth of snow at all events are 

 ruddy — for even snow itself turns reddish with lapse 

 of time ; these have shaggy hair and are of consider- 

 able size, and torpid. 



XLII. Some creatures are generated also by Fire-flies. 

 the opposite natural element. Thus in the copper 



505 



