SUPPLEMENT. 
As stated in the introduction to the present Report, a few 
pages are here devoted to some of those insects which have come 
under my observation, which do not pertain to the noxious class 
but are yet too interesting on various accounts to be withheld from 
the public. The limits, however, to which I find myself restrict¬ 
ed oblige me to omit several species which I had purposed 
noticing. 
210. Emasculating bot-flt, Cuterebra emasculator, new species. (Diptera. 
(Estridse.) 
The history of this remarkable insect will be best presented by 
extracting from my manuscript notes the successive memoranda 
therein entered relating to this subject. 
August 13th, 1856. Peter Reid of Lakeville informs me that 
his cat yesterday brought into the house a striped squirrel ( Sci- 
urus striatus.) On taking it into his hands he noticed its scrotum 
was enormously swollen and hard, with an orifice in it about the 
size of a wheat straw, and on pressing it with his fingers he could 
distinctly feel the writhings of something alive in this tumor. On 
enlarging this orifice with the point of a pen knife he discovered 
it was a large grub lying with its tail to the opening. It dis¬ 
charged at intervals three large drops of a fluid resembling gru- 
mous blood mixed with purulent matter. On pressing upon it so 
as to protrude the tail end of its body slightly out of the open¬ 
ing it.exerted itself to crawl out, forcing its fluids into the part 
which was out of the orifice so that it became swollen and hard, 
and then regurgitating them into the body again, whereby the 
extruded portion became soft and collapsed, thus pressing upon 
and dilating the orifice, so that with three or four repetitions of 
