178 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV11I. 



Fig. 13.— Use of Discs. 



The last thing to be done is to arrange the legs and wings as far as possible. 

 The wings must be made to project at an angle from the body, and not allow- 

 ed to lie closed over it ; if they can be got to remain at 

 right angles to the body, so much the better. In the case of 

 any specimen that is not too small and fragile, the wings 

 can be best arranged by means of the fine pointed forceps, 

 by making a gentle simultaneous pressure with tips of 

 the forceps at the base of each wing, repeating it until the 

 wings assume the desired position. The legs also must be 

 disposed symmetrically (and as far as possible in a natural 

 position) on the card disc, so that all parts of them can be 

 readily seen, and must not be allowed to remain crumpled 

 up beneath the body, since important characters are often 

 found upon them. In the case of a fairly large specimen 

 it will generally be found possible to cause legs to remain 

 in the desired position by hooking the claws on the edge 

 of the disc, gently drawing the legs out one after another 

 by aid of a needle or one leg of the fine-pointed forceps. The manipulations 

 in connection with the legs and wings must be performed as gently as possible, 

 and care must be taken that bristles, hairs, or scales are not rubbed off in the 

 process. As soon as these operations are completed, the specimen should be 

 transferred to a store box, or to one lined with cork-carpet or pith, as de- 

 scribed above. Since, however, the tissues contract in dying, the legs and 

 wings are very apt to get pulled out of place, and, to correct these changes, 

 the specimens should be examined once or twice during the next day or two 

 after being pinned. 



Very minute or fragile specimens (such as Ceratopor/on or Simulium) are best 

 pinned from the side, and the legs should then be straightened out by means of 

 a No. 20 pin held in the entomological forceps. 



diptera collected in the tropics : 

 Attacks by Ants — Mould — Transmission to England. 



In the tropics boxes of pinned insects are very liable to be attacked by minute 

 ants, which if they once gain access to a box unobserved, will soon play havoc 

 with its contents. In Brazil it has been found that ants can be prevented 

 from entering insect-boxes by smearing the outside round the line where the 

 box opens, or any other possible place of entrance, with andiroha oil, repeating 

 the process as often as necessary ; similar methods might be employed else 

 where in case of need. 



Mould, however, is an even greater enemy to collections of Diptera. Pinned 

 specimens of Diptera, like those of other insects, rapidly develop mould during 

 the rainy season in tropical countries ; and since mouldy specimens are practi- 

 cally worthless for purposes of scientific determination, Diptera should ahcays 

 he sent home as soon as possible after being collected. The risk of mould may 



