SHEEP SPIDER FLY. — 121 
breadth,* and within the parent fly the maggot feeds until it is full- 
grown, when it is deposited in a pupa-case. These ‘“ puparia’”’ are not 
little round balls notched at one end like the pupa-cases of the Forest 
Fly, but flatter from back to front, and very bluntly oval in shape, with 
the two ends truncated, so as to be almost of a long-square shape, with 
the four corners rounded off. 
Also the colour is different. The Sheep Tick chrysalis-cases are of 
a clear bright chestnut, where they can be seen, but this is commonly 
more or less hidden by an incrustation of dried matter, which has to 
be cleaned off in order to see the smooth bright coat beneath.| In my 
own specimen (figured from life) it will be seen that about a third only 
of the surface was clean. In the excellent paper by Dr. Cooper 
Curtice on Sheep, published by the U.S.A. Department of Agriculture 
(quoted above), he mentions, regarding deposit of these puparia by 
the Sheep Tick, and the nature of the incrustation, that ‘they only 
lay one at a time in the wool. A portion of each puparium will be 
found to be covered with a dry dark substance, which came from the 
parent when the puparium was laid, was sticky, and glued it to the 
surrounding hairs. This prevents the pupa, which becomes dry, hard, 
and glassy, from falling from the wool.”’ } 
How many of these egg-like chrysalis-cases may be produced by 
one fly does not seem certain. Dr. Taschenberg mentions that 
successively—that is, from time to time—and taking the number of 
single deposits altogether, as many as eight puparia may be produced 
by one Spider Fly. 
In due course the fly matures, and escapes from the case by 
cracking it across near one end. ‘The only note I am aware of as to 
the time taken for development, is that of within four weeks at ordinary 
temperatures, given by Dr. Curtice from his own observations. 
Very few attacks lie so completely under cure by treatment as this. 
It is most especially a sheep attack, though the flies have existed for a 
time on human blood, and they die soon if deprived of food. In the 
case of some scores sent me in wool from sheep which had not been 
dipped, though all circumstances excepting that of presence of food 
were comfortable for them, they died in a very few days. 
The treatment, which appears to do all that is needed in the way of 
application both here and in the States, is the use of dips. On this 
point Prof. Wallace notes, in his ‘ Farm Live Stock,’ speaking of these 
Sheep Ticks (known in Scotland under the name of Kades or Keds), 
* See ‘Die Fortpflanzung und Entwicklung der Pupiparen nach Beobachtungen 
an Melophagus ovinus,’ von Dr. Rud. Leuckart, p. 17. Halle, 1858. 
+ See ‘Etudes Anatomiques et Physiologiques sur les Insectes Diptéres de la 
famille des Pupipares,’ by M. Léon Dufour, p. 84. (Previously quoted.) 
{ ‘Animal Parasites’ (before referred to), p. 49. 
