1896.] 101 



"DRY RELAXING" FOR MICliO-LEPIDOPTERA. 

 BY H. GUARD KNAGGS, M.D., F.L.S. 



It is very gratifying to learn that my friend Mr. Clark's discovery 

 of relaxing insects by means of wood naphtha has yielded results 

 of even greater practical utility than was originally anticipated for 

 it; but admirable as is its action in a general way, it does not answer 

 vi^th small Tineina, the wings of which, as Mr. Eustace Bankes in- 

 formed me on a recent occasion, are apt to cockle, and the cilia to be 

 injured by the slightest contact M'ith fluid of any kind whatever. Mr. 

 Bankes' remarks gave me the cue to make the attempt to devise a 

 means whereby such little things as JSlachistidce, Lithocolletid(S, and 

 NepticulidoB could be relaxed without the application of fluid or 

 deleterious vapour. The following is the outcome of my endeavours. 



Bearing in mind Mr. Philip de la Garde's note (Entom., xxvii, 

 294) that Naphthalin has the power to keep freshly caught insects in 

 a limp state for several days, even when collecting under a tropical 

 sun in Equatorial Africa, this substance was first put upon its trial, but 

 its power to relax insects which had been set for a considerable time 

 was not strong enough for the purpose, though decidedly appreciable ; 

 so that it was considered advisable to supplement its action with a 

 small quantity of the vapour of wood naphtha. Accordingly, having 

 procured an accurately stoppered, wide mouthed, three ounce bottle, 

 a piece of sheet cork was cut in the form of a circle of a diameter a 

 trifle less than the mouth of the bottle, while a long pin, stuck in its 

 centre, served as a handle. Into the bottle two drachms (| oz.) of 

 sublimated naphthalin with six drops of wood naphtha vi'ere intro- 

 duced ; the insects pinned on the stage alluded to above, with their 

 wings kept well away from the cork, were then lowered into the 

 bottle, and the stopper replaced. 



In three hours, roughly speaking, relaxation had commenced, in 

 twenty-four it had greatly increased, it was apparently complete in 

 forty-eight, though resetting could be undertaken at the end of 

 twenty hours. 



The ordinary albo-carbon, w^hich is an impure naphthalin, used 

 for gas-burning purposes, will answer the purpose, but the effect is 

 by no means so satisfactory as that produced by the sublimated 

 article. 



The question naturally rises in our minds— Is the wide-spread 

 use of Naphthalin in our cabinets, as the most convenient preventive 

 of moulds and mites, likely to do mischief ? So far as my present 



