156 



Before forwarding specimens in a store-box 1 through the post, pins- 

 should be tested to see that they are inserted as tightly, as possible, 

 and all should be " driven in to the same level, after which a sheet of 

 soft paper (newspaper does very well) can be fixed into the box," 

 resting on the heads of the pins, in order to minimise damage should a 

 specimen happen to get loose. ' The box containing the specimens, 

 should be well wrapped in cotton-wool or similar material, and firmly 

 packed in an outer case for transmission (by parcel-post if possible and 

 if the package is not too large) to England/' 



PRESERVATION OF SPECIMENS IN ALCOHOL. " Unless intended for 

 dissection," writes Austen, 2 " Diptera must on no account be placed in 

 spirit. Since all descriptions of Diptera have been based upon dried' 

 specimens, flies in spirit have to be taken out, dried, and pinned before 

 they can be examined and compared with descriptions. In drying, 

 however, they invariably shrivel, while immersion in spirit often causes 

 colour-markings to disappear, and inevitably results in hairs, scales, 

 etc., being washed off or matted." " Pinned specimens," however, 

 " should always, if possible, be accompanied by others preserved in 

 alcohol. The following directions have kindly been supplied by Lieut. - 

 Colonel G. M. Giles, who has found that the method indicated answers 

 well in practice : ' Flies intended for anatomical examination must 

 be fixed by heat, since their chitinous envelope is penetrated so slowly 

 by alcohol that, if this be not done, they decompose before the pre- 

 servative can reach them. It is sufficient to bring them to boiling 

 temperature in a test-tube of water, but for delicate histological work 

 it is better to boil in a mixture of equal parts of 90 per cent, alcohol 

 (ordinary rectified spirit) and aqueous solution of perchloride of 

 mercury, 1 in 500. Even protozoal parasites are well preserved by 

 this method. When fixed, preserve in 90 per cent, alcohol. Methylated 

 spirit should not be used, since its acidity and other impurities may 

 lead to embarrassment in the use of aniline stains.' The specimens 

 should be preserved in small glass tubes, with a plug of soft paper placed 

 inside on the top of the specimens to prevent them from being injured 

 by washing about in transit. A slip of paper, on which all necessary 

 data should be written clearly in pencil, should be placed inside each 

 tube, and the pinned specimens of the same species should be labelled 

 with a reference to those in spirit, so that the latter may be identified. 

 The tubes containing the specimens should preferably be placed for 

 transmission inside a larger bottle of spirit ; if this be done, it is only 

 necessary to secure the mouth of each tube by tying muslin over it. 

 Cotton -wool, or, better still, horsehair or shavings, should be inserted 

 as packing between and especially on the top of the tubes " 



PRESERVATION OF LARVAE AND PUPAE. Larvae and pupae of 

 Tsetse-flies, which it is intended to preserve "should be killed by 

 immersion for a moment or two in boiling water, and should then be 

 placed in weak spirit (two- thirds spirit and one- third water) ; after 

 being allowed to remain in this for two or three weeks until 

 thoroughly hardened, they can be transferred to stronger spirit. The 

 larvae and pupae of each species must, of course, be kept separate, and 



1 " Should the collector run out of store-boxes, cigar-boxes, in the bottom of 

 which is fixed a layer of cork-carpet or pith, make efficient substitutes ; but if 

 pith is used, it should not be less than half-an-inch thick." 



2 Instructions for Collectors : No. 5. Diptera (Two-winged Flies). 4th Ed.. 

 P. 8. London: British Museum (Natural History). 1919. 



