104 INSECTS AFFECTING DOMESTIC ANIMALS. 
dots running the breadth of each segment in their middle, whick, 
under the magnifier, appear to be minute brown spines all pointing 
posteriorly (fig. 48,5). These aid the maggot in its movements. When 
ready to contract into a pupa it passes down the nasal passages of 
the sheep and falls to the ground, where it quickly buries itself, and 
in about forty-eight hours contracts to half its former size, and becomes 
smooth and hard and of a black color, tapering, as in the larve, toward 
the head. It remains in this state from forty to fifty days or more, 
according to the weather, when the fly pushes open a little round ecap- 
piece at the head and thus arrives at maturity. In this stage it looks 
something like an overgrown house fly. The ground color of the upper 
part of the head and thorax is dull yellow, but they are so covered with 
little round spots and atoms (searcely distinguishable without the aid 
of a magnifier) that they have a brown appearance. The abdomen con- 
sists of five rings, is velvety and variegated with dark brown and straw 
color. On the under side it is of the same color, but not variegated in 
the same way, there being a dark spot in the middle of eachring. The 
feet are brown, the under side of the head is puffed out and white. 
The antenne are extremely small and spring from two lobes which are 
sunk into a cavity at the anterior and under part of the head. The 
eyes are purplish brown, and three small eyelets are distinctly visible 
on the top of the head. It has no mouth and can not, therefore, take 
any nourishment. The wings are transparent and extend beyond the 
body, and the winglets (calypteres), which are quite large and white, 
cover entirely the poisers. Its only instinct seems to be the continua- 
tion of its kind. It is quite lazy, and except when attempting to 
deposit its eggs its wings are seldom used. 
PREVENTION AND REMEDY. 
To prevent it from depositing its young, different means are resorted 
to. Mr. Randall says ‘‘some farmers turn up the soil in portions of 
pasture so that the sheep may thrust their noses into the soft ground 
on the approach of the fly, while others smear their noses with tar or 
cause them to do so themselves.” But as the fly is very persevering, 
and generally attains her object, the means to be most depended on is 
the dislodging of the larve or grub, and so far lime has been thought 
the most effectual and should be given them so that by sniffing it they 
. may be made to sneeze, and thus dislodge the grub in many cases. Some 
Sheep keepers even shut their sheep up for several nights in a tight 
barn when first taken up in the fall, believing that the close and 
heated atmosphere induces the grub to descend, and is therefore more 
easily dislodged, and that the injury accruing from such foul air is 
trifling compared to the benefit received from dislodging the grubs. 
Other sheep breeders are in the habit of fixing salt logs in their pas- 
tures, of sufficient length to enable all the sheep to get at them. Into 
these logs, at intervals of 5 or 6 inches, holes are bored with a 2-inch 
