i9i4- Carpkntek & Hewitt. — History of Wabble Flies. 215 
in the case of Horse Bot-fly {Gastrophilus equi), the newly - 
hatched maggots — must be hcked in by the cattle, bore 
through the mucous coat of the gullet, and, after resting 
awhile in its sub -mucous coat, work their way to the final 
position beneath the skin of the back. 
In order to ascertain if possible the exact method of the 
young maggot's entrance, experiments and observations 
have been carried on for the past ten years, mostly at the 
Agricultural Station, Ballyhaise, Co. Cavan, under the 
auspices of the Department of Agriculture and Technical 
Instruction. Three reports on the work done have already 
been published,^ and a fourth is now in course of prepara- 
tion. The experiments from which the most important re- 
sults w^ere expected consisted in keeping a number of calves 
through the summer in the field by day, muzzled in such 
a manner that it seemed impossible for them to lick them- 
selves, and tied up b}^ night with their necks in " bales " 
and with broad aprons so that they could not touch their 
fore -limbs with their tongues. Along with these animals a 
number of others were allow^ed to graze naturally. It was 
considered that if the warble-rnaggots enter by the mouth, 
calves muzzled in this way ought to be protected, and to 
show no warbles in the succeeding year. 
A summary of the results of these muzzhng experiments 
may be instructive. In the summer of 1906 six calves were 
muzzled and six unmuzzled grazed in the same field. In 
the spring of 1907 the former had on an average 15-3 
warbles each, the latter lo* 8 ; the muzzled calves w^ere thus 
apparently unprotected, and the result was considered to 
" afford strong support to the old view of the method of 
entrance dircctl}/ through the skin." In 1907 the experiment 
was repeated, with a very different result. Of the calves 
subjected to the muzzling test only two survived till the 
next spring, when these were found to be entirely free from 
warbles, while the twenty-nine unmuzzled animals, on the 
other hand, had an average of 77 warbles each. This might 
^ Journ. Dept. Agric. Tech. Instr. Ireland, vol. viii., 1908, pp. 227-246 ; 
vol. ix, 1909, pp. 465-476 ; vol. X. 1910, pp. 642-650. 
