8 
the Cervical, but which might better be called the Face 
or Nostril- and -Throat Flies, of which the Sheep Nostril- 
Fly, CEstrus ( Cephalemyia ) ovis, is amongst our regular 
sheep pests. 
But in whatever part of the body, he it of our animals 
(or possibly of ourselves), these various maggots may 
feed, they are for the most part thick, fleshy, legless 
grubs, furnished with minute tubercles or spines, often 
set in rings round them ; and it appears that they have 
little, if anything, like a regular form of mouth, but 
rather an opening more or less furnished with tubercles, 
which serves for the entrance of the fluid on which they 
feed, and in some instances the mouth-opening of the 
maggots is furnished with a pair of hooks, by which they 
attach themselves to the surface on which they feed. 
When full-fed they leave their position, and fall or make 
their way from the nostrils, hide, or whatever it may be, 
in or on the animal, and, like many of our crop maggots, 
they seek a shelter in the earth, or under a stone, or in 
some convenient place, where they rest while the maggot - 
skin contracts and hardens into a chrysalis-case, from 
which presently the Fly appears. 
It is laid down that for the most part each species of 
this family of the GEstridce only attacks some one species 
of animal, for instance, that there are Bot Flies which 
attack horses, or cattle, or sheep, or deer, or goats, or 
many other animals, but that with few exceptions each 
kind of Bot Fly limits its attack to what we may call its 
own animal, and likewise to its own special portion of it. 
The CEstridce are stated to be found in all parts of the 
world excepting New Holland, where, up to 1868, the 
date of the notes by Brauer, from which I quote, they 
appear not to have been observed. But, without going 
into discussions on the different kinds which occur in 
different countries, it is well worth while to notice that 
difference of climate cannot be trusted to as a means of 
destroying them, and this is most particularly the case 
with regard to two of the commonest kinds that infest 
the horse. The larvse travel within the living host, and 
