4 
WARBLE FLY. 
outside of tlie hide. These channels (of course examined microscopi¬ 
cally) had no lining membrane as is the case further on; they were 
merely a passage (see fig. 2) apparently 
gnawed or torn by the mouth-forks of the 
young maggot, and they varied in direc¬ 
tion, being sometimes slanting, or taking 
a straight course, or so completely curved 
at the upper part, that it was quite im¬ 
possible that this channel could have 
been caused by the perforation of the 
ovipositor (the egg-laying apparatus of the female fly), and in one 
instance in which the maggot-tunnel had only gone about half the 
way through the hide I found a small soft body lying at the bottom, 
which, though crushed in taking the section, appeared without doubt 
to be the maggot. 
The egg is of the shape figured at p. 1, and is thus described by 
Prof. Riley, late Entomologist of the U. S. A. Department of Agricul¬ 
ture, from his own personal observations of warbled cattle in Illinois 
from 1860-18G3, when interested directly in stock-raising, and having 
the charge of some three hundred head of cattle* :—“ . . . The eggs 
of this Ox Bot are elliptic ovoid, slightly compressed, and have at the 
base a five-ribbed cap on a stout stalk with which to strongly attach 
them to the skin of the animal.” Prof. Riley remarks that the grooved 
and slightly pedicelled enlargement of the end which is attached is 
admirably adapted for being strongly fastened to the skin, and to the 
base of the hairs, and all observations that have been recorded point 
to the fact that the young larva works its way directly from the egg 
under the skin. “ . . . The structure of the ovipositor clearly excludes 
the possibility of puncture, for though horny, it has a blunt trifid tip, 
and is beset at the end with certain minute hairs.” 
The point of where the egg is deposited is very important relatively 
to effect of dressings, and there has been a great deal of what cannot 
but be considered vague speculation on the subject, as few of 
authority, excepting Prof. Riley, speak from observation. But we 
know that the ovipositor is not suited for purposes of boring ; also 
I can speak personally to the borings through the hide not being 
such as could be formed by the passage of an ovipositor, and in 
the absence of any evidence from observation of the eggs being 
passed down through the hide, I believe that all the different points 
which we know from observation prove that the deposit takes place on 
the outside. 
* See ‘ Insect Life.’ Periodical Bulletin of U. S. A. Department of Agriculture, 
Yol, ii., No, 6, pp. 173,174; Washington, U. S. A., 1889, 
