45 
tery became unravelled; for I was not certain, indeed apprehended 
after such authority, that the same species inhabited both animals 
as Linnaeus had stated, “ Habitat intra Bourn dorsum, in ventri- 
culo Equorum saepe ipsis lethalis.” Lin. Syst. Nat. p. 969- This 
insect was not known to Linnaeus, and, indeed, has been rarely 
seen; Vallisneri, after years of labour, procured only one muti¬ 
lated specimen of it; and Reaumur, after great pains and expence, 
only two or three. A mode of obtaining this fly, which suc¬ 
ceeded with me perfectly well, I shall now describe, by which I 
obtained out of three larvae two perfect flies, one so perfect, that 
it flew away while I was making some experiments in presenting 
it with different objects; the other I gave to Thomas Allen, Esq. 
after drawings had been made from it for the use of the Linnaean 
Society. One I also fortunately caught of these flies, between 
Salanche and Bonneville, in Savoy, flying in the road, and settling 
on some dung where cattle had recently passed ; this specimen, 
on my return through Germany, I presented to the venerable and 
worthy Professor Daniel Schreber, of Erlang, the intimate friend 
and pupil of Linnaeus, who till then had not seen it. 
The following is the simple means for obtaining them perfect, 
w r hich may be not unacceptable to those who for their cabinets or 
from curiosity may wish to see them : 
During the latter months of the summer, about which time 
the larvae are found fully grown, and about to quit their habita¬ 
tions, which can be known by the superior size of the abscess, 
and especially the increased diameter of the external opening ; 
such being selected for the experiment, we remove the hairs 
round the tumor to a considerable distance with a pair of scissars 
as close to the skin as may be ; and a piece of leather, thickly 
spread with, pitch, being provided, through the center of which a 
hole is cut about the size of the finger, and into this a small 
gauze pouch or bag is inserted, hanging out an inch or two from 
the leather: this plaister with its pouch is then placed upon the 
M 
