THE LITERARY 



OF THE LINNiEAN ASSOCIATION OF PENNSYLVANIA COLT-EGE. 



Vol. I. 



MAY, 1845. 



No. 7. 



OBSERVATIONS ON THE BOTS IN HORSES, NO. II. 



OESTRUS EQUI.. 



In the last number of this Journal, I described two species of this 

 genus, which infest the ox and the sheep, and shall devote this paper to 

 that one which is jmr eminence designated as the hots^ and is peculiar 

 to the horse. It is very commonly found in the stomach of this ani- 

 mal — a remarkable location, indeed, for the habitation of an insect in its 

 larva or grub state. It is represented in fig. 1. These larvae attach 



themselves to every part of the stomach, and are sometimes, though 

 less frequently, found in the intestines. Fine specimens attached to 

 sections of a horse's stomach, preserved in spirits, are exhibited in the 

 cabinet of the Linnaean Society of this Institution, presented by Dr. 

 Jacob Hay, of York. 



Their numbers in the stomach arc very various, often not more than 

 half a dozen, at other times more than a hundred. They hang most 

 commonly in clusters, by means of two small hooks at the smaller end 

 of the animal, of which an enlarged representation is given in fig. 2. 



When they are removed from the stomach alive, they will attach 

 themselves to any loose membrane, and even to the skin of the hand. 



The body of the larva is composed of eleven segments, and it evi- 

 dently receives its food at the small end by a longitudinal aperture, 

 ■which is situated between the two hooks. Its food is probably the 

 chyle, which being nearly pure aliment, may go wholly to the compo- 

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