308 
The eggs, so far as the observations of my correspondent go, have 
failed to hatch when removed from the animal and placed in moist sit- 
uations, but an examination of some received, which were placed in 
alcohol as soon as collected, shows that the larve in them were already 
fully developed. Im fact, there is every reason to believe that, as in 
the case of so many other Diptera, the embryon is already fully devel- 
oped when the egg is laid—which confirms the view that the larva is 
licked up by the tongue of the animal either directly out of the egg, as 
in the case of that of Gastrophilus equi, the Horse Bot, or, as must more 
often happen, is taken with the egg still attached to the hair, as the 
egg-laying season is coincident with the shedding season. and cattle 
have a great habit of licking themselves at this particular time, thus 
taking a great deal of hair not only into the mouth, but, as we know, fre- 
quently into the stomach as well, where it forms the well-known hair- 
balls. In either event the larve would seem to need the heat and 
moisture of the animal’s saliva for their well being. That the larva is 
easily released from the eggshell is shown by the fact that the shell 
splits open very readily at its anterior end. 
When we come to look more closely into the matter, the old idea that 
the larve enter directly from the egg into the animal through the skin, 
seems otherwise quite untenable, for the delicate larva which would 
hatch on the flanks, legs, and tail of the animal would scarcely be able 
to wander to the back and penetrate the skin in the locations where 
the warbles are always found, all of which lends confirmation to the 
views here presented, viz, that the larva is licked into the mouth and 
wanders as described, through the esophagus into the subcutaneous 
tissue, finally reaching the dorsal region. 
The observations here recorded render significant the fact that this 
insect is known by stockmen, particularly throughout the South and 
West, as the Heel Fly, a name which has originated from the fly hayv- 
ing been noticed in some instances to oviposit on or near the heel of the 
animal. Thus of ten reports received from stockmen in Texas, seven 
say that the fly oviposits on the heel or just above the hoof, two on the 
belly and sides, and one did not know.* 
It would thus seem that the normal place of oviposition, when the 
animals are on their feet and moving, is somewhere near the heel, from 
which the popular designation comes, and judging from the habits of 
other bot-flies, in which the method of oviposition is characteristically 
distinct, we may safely conclude that the method here described is the 
~ Mr, Conrad L. Fuchs, Tiger Mill, Burnet County, Texas, writes, in substance, as fol- 
lows: ‘‘ When I was using a half-broke ox team some fifteen years ago I could not 
work them (on account of this fly) without keeping their heels smeared with Kero- 
sene. This I applied by means of a rag tied to a long stick. The steers soon learned 
the benefit and would allow me to apply the oil without kicking. The fly would 
hesitate to oviposit (‘take a hold or sit to the heels’), thus giving a chance to see it, 
Except for this hesitation it could not be seen because of its quick flight. 
