THE COLLECTION AND PRESERVATION OF DIPTERA 151 



THE COLLECTION AND PRESERVATION 

 OF DIPTERA. 



By Percy H. Grimshaw, F.E.S., F.R.S.E. 

 ' Concluded from page 61. 



Preservation. 



The preparation of flies for their permanent place in the 

 collection is an extremely simple process. It consists merely 

 of the three operations of pinning, staging, and labelling. In 

 the pinning of Diptera it is extremely desirable to use the 

 finest pin possible, otherwise the all-important bristles may 

 be seriously damaged or rendered difficult of observation, 

 and for all but the largest species No. 20 of Messrs D. F. 

 Tayler & Co.'s series of entomological pins is the most 

 generally useful. For specimens the size of a Bluebottle 

 and upwards No. 7 of the same makers is quite large enough; 

 while on the other hand for the tiny midges and the like it is 

 necessary to use the finest pins procurable, preferably those 

 of silver wire made for Microlepidoptera. In the writer's 

 experience gilt pins have proved of little advantage, but a 

 carefully enamelled black pin has a neat appearance and 

 prevents the formation of verdigris. The pin should in every 

 case be thrust through the thorax, and either through the 

 dorsal (upper) surface or one of the sides. Certain advan- 

 tages accrue to each method, but in the writer's opinion the 

 balance is in favour of side-pinning. After a long experience 

 it has been found that pinning the fly through the left side, 

 the pin entering the thorax immediately in front and at the 

 level of the attachment of the left wing is the best, generally 

 speaking, the pin emerging at a corresponding spot in the 

 right side. The fly is then carefully pushed up the pin until 

 only about a sixteenth of an inch is left projecting above. 

 The head of the pin (if it has one) may be carefully cut off 

 with a pair of wire cutters, which must be of thoroughly good 

 quality and sharp enough to cut the pin without jolting the 

 insect, otherwise a precious head or limb may be lost in the 

 operation. The flies to be pinned should be strewn over 



