2 BULLETIN 597, U. S. DEPARTMENT OF AGRICULTURE. 
to meet the great demand for army horses. Within the nose-fly dis- 
trict is to be found one of the largest horse-sale points in the world. 
BRIEF LIFE HISTORY OF GASTROPHILUS. 
Our knowledge of the life histories and habits of these insect 
pests, which is always essential to successful control, is confined for 
the most part to the classical accounts of Bracy Clark in 1797 and 
subsequently, although later writers have added important details. 
When the female of Gastrophilus intestinalis (G. equi) becomes 
sexually mature it is most often observed hovering near the inside 
of the knee of a horse, where by preference the eggs are deposited. 
After a few days, when the larve develop within the eggs, the horse 
by scratching the forelegs with the teeth provides sufficient moisture 
and friction to remove the operculum or small cap of the eggs and 
inadvertently the larve are taken within the mouth. The empty 
eggshells remain attached to the hairs of the legs, whereas the 
larve are carried with the food or water to the stomach, where 
attachment to the stomach walls takes place. Here they undergo 
development during the autumn, winter, and spring months, and 
later are passed from the horse with the manure. At this stage pupa- 
tion ensttes and adult flies are produced. ; 
The other species of bots also spend similar larval periods in the. 
animal, but have habits peculiar to the particular species. 
HISTORICAL. 
The literature containing historical references to the Oestridae 
carries one to a most remote time. The ancient Greeks and the 
Latins refer to “an unspeakable fright of cattle,” though later 
writers are not agreed as to whether it was produced by an oestrid 
or a tabanid. It is certain, however, that Aristotle knew the forms 
found in the throats of deer. 
The Greek veterinarians Theomnestus and Absyrtus give us the 
earliest record which could be referred to Gastrophilus when they 
write of the “biting worms which fix themselves to the anus of the 
horse.” In order to destroy them it was recommended that they 
be torn from the anus with the fingers and covered with hot ashes 
and pulverized salt. 
Malpighi in 1697 gave the first description of a gastrophilid larva 
taken from the stomach of an ass. According to Joly, it belonged to 
the species G. intestinalis De Geer, while to Brauer it was @. flavipes 
Olivier. Gaspari published an erroneous opinion that G. haemorrho- 
idalis deposited its eggs in the rectum of the horse during def- 
ecation, and that the larve migrated to the stomach until about 
fully developed. Vallisnieri and Réaumur made the same erroneous 
diagnosis. 
