20 [January, 



for this reason that relaxation is not desirable, as the potash is apt to 

 enter the bodies and loosen the limbs o£ relaxed specimens. 



Light colours are sometimes found to be darkened after cleaning, 

 but they seldom if ever fail to return upon thorough drying. If a 

 metallic or polished surface appears tarnished, as sometimes though 

 rarely occurs, the tarnish can be at once removed by a drop of chloro- 

 form, and will not reappear. 



The verdigris and dirt are removed from the pin, which is un- 

 affected by potash, the former, if in lumps, will require picking off with 

 a needle ; the pin is almost always loosened in the body, and can be 

 fixed with a touch of shellac on the under-side, or .better, withdrawn, 

 especially if corroded, and a fresh one substituted. 



If the beetle is carded, the upper surface of the card alone should 

 be allowed to touch the potash ; the insect should be cleaned with 

 brush and water on the card, but will soon become detached, and after 

 immersion in water to remove the potash, should be laid on moist 

 blotting paper for the cleaning to be completed, dried and recarded. 

 Staged specimens with the pins cut short are troublesome to clean, 

 but the difficulty is one of manipulation. 



The whole time required between removing a dirty insect from 

 a collection and returning it cleaned and re-pinned does not usually 

 exceed fifteen minutes, much of which can be occupied in treating 

 other examples. 



Specimens so cleaned have shown no signs of subsequent deterio- 

 ration. Whether mould is apt to recur on them under suitable 

 conditions I cannot say ; the potash and alcohol must kill the hyphae 

 as far as they soak into the body, and there can be no objection to 

 giving the insects the final immersion into alcohol containing carbolic 

 acid, or, if preferred, corrosive sublimate (1 grain to 4 ounces). 



I have used this treatment with fair success in cleaning Heteroptera, 

 which require, however, very delicate handling, and even Hymenoptera 

 and Diptera. But the latter are troublesome, as the hairs become 

 matted, and it is difficult to prevent the wings from becoming pleated. 



Though it is possible with practice to thus clean insects belonging 

 to the latter Orders, I should hesitate to recommend it at present ; 

 but any one with a quantity of mouldy specimens can easily experiment 

 on, and perhaps save material which he would otherwise have consigned 

 to the rubbish heap. 



48, Wimpole Street, W. : 

 October, 189i. 



