32 



Preparation of the Larva of Lepidoptera. 

 Mr. Stainton read the following communication from Dr. Collingwood : — 



" The preparation of the larvoe of Lepidopterous insects has long been a deside- 

 ratum : while the imago requires but little management, being, with the exception of 

 those that ' run greasy,' little prone to decay, the caterpillar form, on the other hand, 

 being soft and juicy in the extreme, cannot possibly be preserved in our cabinets 

 without undergoing some process, which, however effectually it may preserve it, as 

 certainly destroys the symmetry of form and delicacy of colour of these perishable, 

 though often beautiful subjects of entomological study. 



" In my frequent visits to the Imperial Cabinet of Zoology at Vienna, I could not 

 fail to be struck with the extremely beautiful preparations illustrative of the transfor- 

 mations of insects, exhibited in the upper story of that establishment. In glass cases 

 suspended against the walls is a most instructive series of insects in every stage of 

 their remarkable career, and preserved in a perfection of beauty I have nowhere seen 

 paralleled. This series appeared to be very attractive, and was generally thronged 

 with humble admirers, who probably saw, for the first time, and to their great 

 astonishment, the various changes which insects undergo. But among the forms 

 thus preserved, the caterpillars were pre-eminent ; their unchanged forms, delicate 

 colours and characteristic attitudes, looking exactly like life. 



" Thinking that British entomologists would be glad to be able to add to their collec- 

 tions similar specimens, I determined, before quilling Vienna, to learn the process by 

 which they were prepared. Unfortunately, however, I found that the director, Herr 

 Redtenbacher, to whom I looked for information, was absent; but this circumstance 

 was, to a great extent, remedied by the kindness of my friend Dr. Ernst Briicke, 

 Professor of Physiology in the University of Vienna, who, in a letter lately received, 

 has given me the following information, derived from Herr Redtenbacher: — 



" The caterpillars, he says, are eviscerated through ihe anus, and the skin is then 

 blown out, being fixed upon a tube ('man bloss sie an einen Tubiilus befastigt 

 ai'if '), and carefully held all the while over a pan of hot coals, until they become 

 quite dry, and are no longer liable to change their form. Caterpillars with peculiarly 

 delicate colours, such as green or pale rose, are liable of course to lose their colours in 

 this drying process. To replace them, a mass of wax, of the natural hue of the 

 insect, is poured in through the opening by which it was eviscerated. 



"The Professor adds, that the beauty of these preparations, as seen in the 

 Imperial cabinet, depends less upon the nature of the method than upon the manual 

 dexterity of the operator, assisted by long practice. I doubt not, however, that many 

 members of the Entomological Society possess this dexterity to an extent quite great 

 enough to produce specimens equal to those I have described, especially when the 

 hope of enriching their cabinets has induced the practice necessary to the attainment 

 of perfection." 



