
















THE INSECT WORLD. 

60 
of a glutinous liquid with which they are provided, and which 
Bi soon dries. This is repeated at very short intervals. It often 
i happens that from four to five hundred eggs are thus deposited 
upon the same horse. Guided by a marvellous instinct, the 
female Cistrus generally places her eggs on those parts of the 
4a horse’s body which can be most easily touched with the tongue, 
that is, at the inner part of the knees, on the shoulders, and rarely, 
on the outer part of the mane. 
Horses are much afraid of the attacks of these insects. Their 
skin contracts where the (strus deposits its eggs, and the effects 
) of the bite soon become serious. 
The eggs of the Gstrus, which are white and of conical form, 
adhere to the horse’s hair as shown in Fig. 43. They are 
me furnished with a lid, which at the time of hatching opens, to 
allow the exit of the young larva, which takes place, according 


















> 
7 
Fic. 43.—Eegs of the Gad-fly (estrus (gustrus) equt) deposited on the hairs of a horse. 
So £E g q / 






} to M. Joly, about twenty days after they are deposited. In fact 
it is not in the egg state, but really in that of the larva, that 
the horse, as we shall explain, takes into his stomach these 
parasitical guests to which nature has allotted so singular an abode. 
When licking itself, the horse carries them into its mouth, and 
afterwards swallows them with its food, by which means they : 
enter the stomach. It isa remarkable fact that itissometimes other | 
| insects, as the-7. abani for instance, that by their repeated stinging | 
cause the horse to lick himself, and to thus receive his most cruel 
| enemy. In the perilous journey they have to perform from the 
| skin of the horse to his stomach, many of the larve of the @strus, 
as may be supposed, are destroyed, ground by the teeth of the 
animal or crushed by the alimentary substances. There is hardly 
| one Céstrus in fifty that arrives safely in the stomach of the horse, 
, and yet if one were to open a horse attacked by @stri, the stomach 
would be nearly always found to be literally full of these larvee. 
