122 
SHEEP-NOSTRIL MAGGOT. 
same period, and when a number of maggots, up to over an inch in 
length, have forced themselves not only into the nostrils, but as far as 
they can go into the cavities above, the symptoms of discomfort or 
serious suffering in the front of the head may very likely agree in 
some respects with those of gid. 
The method of attack of the Nostril-maggot Fly consists in laying 
her eggs, or living maggots as the case may be, in (or by the opening 
of) the nostrils of the sheep. 
These maggots work their way up the nostrils by means of a pair 
of hooks with which they are furnished, which are placed near the 
mouth opening, and also (I should say from watching their method 
of progression) by help of a pair of tubercles placed at the tail with 
which they can push themselves forward, as well as by the adhesion of 
the under side of the maggot to the coating of the nostrils. The maggots 
grow to be from rather under to rather over an inch in length, and of 
the thick somewhat oval shape figured (p. 121), and white when young, 
afterwards with dark or yellowish cross-bands. The brown breathing 
pores or spiracles, like those of the Ox Warble grub, are at the end of 
the tail, but are somewhat differently shaped. 
The maggots feed in the nostrils, or high up in the frontal cavities, 
and are especially to be noticed about May or June. They are said 
to feed in the nostrils for a year ; when full-fed they fall out of the 
nose, or may sometimes be sneezed out, and make their way into the 
surface of the ground in a short time (considered to be from twenty- 
four hours to two or three days), where they turn to a brown chrysalis, 
from which the fly comes out in about six or eight weeks. 
This two-winged fly (figured magnified) is mottled light and dark 
over the back, and the precise shades of tint variously described by vari¬ 
ous writers. From comparison of my own with descriptions I should 
say that it might be called spotted or mottled with ash grey and 
black between the wings, and the abdomen also spotted with black and 
yellowish white, with a silvery lustre when alive; wings colourless 
and transparent; legs yellowish brown. 
Amongst the heads which were sent me for examination, and 
carefully opened, we found some of sheep which had been ill of the 
staggers, or what was thought bad attack of “ giddiness,” had the 
cyst in the brain, of which the following figure, copied from one given 
by Dr. Cobbold in his ‘ Internal Parasites of our Domesticated Animals,’ 
gives an idea ; but we could not find any trace of maggot presence either 
in the brain or nostrils of these, and where I found maggots they 
were quite in the part of the nostrils or passages external to the 
brain. 
The various specimens of maggots sent me afforded excellent 
opportunity for investigations of structure, and showed this to be 
