286 INSECTA. 
in the lumps or tumours formed on the skin, others in some part 
of the interior of the head, and the rest in the stomach of the ani- 
mal destined to support them. The eggs that produce the first are 
deposited by the mother under the skin by means of a squamous 
ovipositor composed of four tubes fitting one within the other, arm- 
ed at the end with three hooks and two other appendages. This 
instrument is formed by the last annuli of the abdomen. These 
larve called taons by the farmers are not compelled to change their 
domicil, finding themselves when hatched in the midst of the puru- 
lent matter on which they feed. The ova of the others are simply 
deposited and glued to various parts of the skin, either in the vicinity 
of the natural cavities into which the larve are to penetrate and 
take up their abode, or on those spots which the animal is in the 
habit of licking, in order that the larve may be transported on its 
tongue into its mouth, where they can proceed to their destined” 
dwelling. Thus the female Gstrus ovis places her eggs on the in- 
ternal margin of the nostrils of the Sheep, which is no sooner aware 
of it, than it becomes agitated, strikes the earth with its feet and 
flies, with its head to the ground. The larva insinuates itself into 
the maxillary and frontal sinuses, and clings to their lining mem- 
brane by means of the two stout hooks with which its mouth is 
armed. It is thus also that the Cstrus equi deposits her eggs at 
intervals, without alighting and by balancing her body in the air, 
on the inner side of the legs of the Horse, on the side of the shoul- 
ders, and rarely on the withers. The Gi. hemorrhoidalis, whose 
larve also inhabit the stomach of the same animal, places her eggs 
on his lips. The larve cling to his tongue, and descend through 
the esophagus into the stomach where they feed on the humour se- 
creted by its lining membrane. They are usually found round the 
pylorus, and rarely in the intestines. They are frequently suspend- 
ed there, in clusters, in great numbers. M. Clark however is of 
opinion, that they are rather useful to the animal than injurious. 
The larve of the Géstri are usually conical and destitute of feet. 
Their body, exclusive of the mouth, is composed of eleven annuli, 
covered with little tubercles and small spines, frequently arranged 
like cords, that facilitate its progression. The principal organs of 
respiration are situated on a squamous plane of the posterior extre- 
mity of body, which is the largest. It appears that their number 
and disposition are differentin the gastric larve. It also seems that 
the mouth of the cutaneous larve is only composed of mammille, 
whilst that of the internal ones is always armed with two stout 
hooks. ; 
Both kinds, having acquired their growth, leave their abode and 
