BLOOD-SUCKING INSECTS AND TROPICAL DISEASES. 177 



When, however, it is impossible to pin them, Diptera may be preserved in 

 fine sawdust, on which a few drops of dilute carbolic acid should be sprinkled 

 to prevent mould. Each specimen, before being placed in the sawdust, should 

 be loosely screwed up in fine tissue-paper (cigarette-paper would do), on which 

 the necessary data (see below under " Pinning ") should be written in pencil. 

 To contain the specimens a small tin box (such as those in which tobacco is 

 sold) should be used ; and to prevent injury from shaking, the box should be 

 packed quite full of sawdust and specimens. 



Diptera may also be put away for transport in three-cornered envelopes of 

 soft paper (newspaper), after the manner in which butterflies are packed by 

 collectors ; but this method does not suit thick-bodied flies, such as Tabanidce, 

 as these are often crushed by it, and if once flattened cannot be restored to 

 their natural shape. Envelopes containing Diptera or other insects may be 

 conveniently packed in tin tobacco or biscuit-boxes for transmission by parcel- 

 post from 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 legibly on it all the data connected with the 

 specimen to be pinned, as follows : (1) name of locality, including altitude if 

 necessary ; (2) date — day, month, year — thus, 20. 11. 06 ; (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 porter's 

 back " ; " At watering-place m stream " ; " Running on banana leaves." Long- 

 er 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 coitu with B " ; " B—in coitu with A." 



Place the disc on which the above particulars have been written, plain side 

 uppermost, 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 it through the centre of the thorax of the 

 specimen, until about ^ inch protrudes beneath. Next grasp the pin with the 

 forceps near the tip, and thrust it through the disc, drawing it well down. 

 Lastly, thrust an ordinary pin through the disc near the margin for the pur- 

 pose of carrying both disc and specimen, and draw the disc a good half-way 

 up the carrying-pin. 



* Should this be not likely to be found in an ordinary atlas, the name of the nearest well 

 known town, or river, bay, mountain, etc., or the approximate geographical position should 

 be added. 

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