26 BOARD OF AGRICULTURE. 
be found on one horse. In depositing the eggs, the female 
fly hovers around the horse, and as each egg is ready to be 
deposited, she quickly advances and bends the abdomen for- 
ward, with the egg at the end, and applies it to the hair, to 
Figure 26. 
Figure 25. 
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which it instantly adheres by the glutinous secretion which 
covers it. She then retreats and prepares another egg for 
the same operation. This does not disturb the horse, unless 
by a tickling sensation, causing the muscles of the skin to 
contract with a tremulous motion. The eggs contain more 
or less perfectly developed larvae when laid; and when they 
are mature, or have been a few days attached to the hair, 
they burst open and allow the young to escape almost instan- 
taneously, when moistened. Thus, when the horse licks itself 
or its companions, the moisture hatches the eggs, and the 
young larve are transferred to the mouth by the tongue or 
lips, and thence to the stomach, where they fasten themselves 
to the lining taembrane by their two hooks. They genérally 
occur in clusters, and are most common in the vicinity of the 
pylorus, but are found attached to all parts of the stomach. 
In this situation they slowly grow to be large fleshy larvee, 
with a round body, about an inch long (Figure 25). The 
segments of the body are provided with double rows of spines, 
pointing backward. These are reddish with black tips. The 
Figure 25.—Bot-fly of the horse (Gastrophilus equi Leach), female, natural 
size. 
Figure 26.—Larva of the same, enlarged. From Packard’s Guide. 
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