11 
* then enlarged into a flattish bag-like shape, more or less concave 
at the tail extremity. (See figure of fly, magnified.) 
A very noticeable part of the structure is that of the feet, which 
much resemble those of the Forest Fly (for figure, see index), and 
are each terminated by a pair of strong black curved claws, each 
furnished with a much shorter and lumpy or somewhat tlmmb-like 
side claw, and a bearded bristle or feather-like appendage of the 
same nature as the “bearded hair” of the Forest Fly’s foot, but 
much shorter and broader in proportion. By means of these claws 
the flies are enabled to cling tenaciously to the wool, and it is 
supposed that the “bearded hair” may, by being curled round 
portions of wool in the sheep’s fleece, help the “ Sheep Ticks” in 
moving about; but this point appears rather conjectural. 
The method of propagation is for the maggot of these pupa¬ 
bearing flies (belonging to the division Pupipara) to be hatched 
within the female fly from an egg, which is recorded by Dr. Leuckart 
to be long and slender in shape, rather more than the twenty-fourth 
part of an inch in length, and about half that measure in breadth. 
Within the parent fly the maggot feeds until it is full-grown, when 
it is deposited on the point of turning to a puparium, or chrysalis. 
These puparia are of the shape figured, from life, at p. 10; that 
is, bluntly ovoid, with the two ends truncated so as to be almost of 
a long square, with the four corners rounded off. The colour, 
where it can be seen, is of a clear bright chestnut, but this is often 
hidden by an incrustation (see figure), which is stated to be sticky 
when the puparium is laid, and to glue it to the wool. 
In the course of 1895 such a good supply was sent me in wool 
of live “ Sheep Ticks ” from fleeces of sheep that had not been 
dipped, that I was able to study the flies and the chrysalis-cases 
carefully, and, amongst other points, noticed the incrustation as 
figured. But in the past season when a small consignment of flies 
was sent just at the time of pupa-laying, I did not notice the 
coating, and therefore conjectured that it was not always present. 
The puparia are laid one at a time in the wool; but with regard to 
the numbers laid successively by one fly there is a difference in 
opinion, some stating that each female only produces one or two, 
others that eight or nine may be successively laid by one fly during 
her life-time. Dr. Tasclienberg, the well-known German entomo¬ 
logist, considers that one Spider Fly may produce in the course of 
her life as many as eight puparia. 
From these “cases” the fly comes out in due course; but I 
have not been able myself to record length of time required for 
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