DIPTERA (TWO-WINGED FLIES). 
71 
abroad. A few drops of weak carbolic acid should be sprinkled over 
each layer of envelopes, and the box should be packed quite full. 
It is never advisable to put Diptera for transmission from abroad 
into small boxes containing wool, as when flies are once in contact 
with wool, and have become dry, it is very difficult to remove them 
without pulling off legs, bristles, etc. 
Pinning. 
Take a card disc, and write on it all the data connected with the 
specimen to be pinned, as follows : (1) name of locality, including 
altitude if necessary ; (2) date — clay, month, year — thus, 6. 3. 99 ; 
(3) collector's name ; (4) any brief remarks of interest (which may if 
necessary be written on the other side) — e.g. "Very common"; 
" Only specimen seen " ; " On dead antelope " ; " At blossom " ; 
" Running on banana leaves." Longer notes on habits, etc., should 
be entered in a note-book, with a number corresponding to one 
written on the disc. Specimens taken in coitu, for which a good 
look-out should always be kept when collecting, should have the 
fact noted on the disc of each, thus : " A — in coitit with B " ; 
" B — in coitH with A." 
Place the disc on which the above particulars have been written 
on a sheet of cork-carpet or pith, and, picking up with the forceps 
an entomological pin (a No. 20 if the specimen is not larger than 
a Blue-bottle, otherwise a No. 7 or No. 5), thrust about ^ inch 
of it through the centre of the disc ; in doing this the pin should 
be held by the forceps below the middle, otherwise it may bend 
and fail to pass through the card. Lay the specimen on its back 
(turning it over with the aid of a needle or an entomological pin 
held in the forceps), and thrust" the pin, which now carries the 
disc, through the centre of the thorax, between the bases of the legs, 
until the tip of the pin projects from J to | inch beyond the dorsal 
surface of the thorax. It is important that, in this method of pinning, 
the pin should project well beyond the thorax, otherwise, when the 
specimen is dry, it may become loose and fall off. Invert the disc 
(the specimen will then be right side up), and thrust an ordinary 
pin through it near the margin for the purpose of carrying both disc 
and specimen, drawing the disc a good half-way up the carrying-pin. 
