318 SETTING AND PRKSmVIXG IXSECTS. 



INSECTS. 



Entomologists are generally satisfied if they can obtain the insect 

 in its last or perfect state; hut as a few instructions for the preserviv 

 tion of the egg, larva, ami pupa may induce the collector to enrich 

 his cabinet with such specimens, and which is absolutely necessary in 

 gaining a perfect knowledge of their nature, I shall give a few parti- 

 culars for this purpose. 



The E"i:. Tiie eags of most insects retain their form and colour 



well if preserved in the cabinet : but those w hich do not promise fairly 

 may be prepared after the niclhod practised by Swammerdam. He 

 used to pierce the eggs with a \ery tine needle, and })ress all tlie con- 

 tained juices through the aperture: he then iutlaled them until they 

 regained their jjroper form by means of a small glass tidie; and 

 lastly, filled them with oil of spike in which some resin had been dia- 

 solved. 



T/ic Larva or Caterpillar. — The preservation of insects in this state, 

 is not only one of the most curious, but useful discoveries that have 

 been made in this department of science. 



The readiest and quickest way of destroying the life of the cater- 

 pillar is to immerse it in spirits of wine, by which means the softness 

 fuid transparency of the parts are retained, and arc preserved tor a 

 length of time in this liquid. 



In the cabinet of jNIr. William Weatherhead are preserved many 

 larvffi of the Lqndoplcra, which he prepares in the following way, and 

 which answers extremely well — Having killed the animal in spirits of 

 wine, he makes a small incision or puncture in the tail, and very gently 

 pressing out all the contained humoiu-s, fills the skin with very fine 

 dry sand; the insect is thus again brought to its natm-al shape: in the 

 course of a few hours the skin dries, and the sand is gently shaken out : 

 it is then gummed on a piece of card, and the preparation is ready for 

 the cabinet : they may likewise be injected with coloured wax. There 

 is another method which is frequently practised, and is as follows : 

 After the whole of the entrails are pressed out, a glass tube drawn to 

 a small point is inserted into the opening, through which the operator 

 continues to blow while he turns the skin at the end slowly round a 

 charcoal fire; this hardens the skin equally, and dries up all the mois- 

 ture within; a pin is then put through it to fix it in a standing posi- 

 tion : it may afterwards be anointed with oil of spike in which some 

 resin has been dissolved, unless it is a hairy caterpillar. 



The Pnpu.—\\\wn insects have quitted the pupa state, the case will 

 require only to be ])ut into the drawers ; but those which have insects 

 within must be either dropped into scalding water, or inclosed in a 

 small tin box and exposed to the heat of a fire, which will shortly 

 kill the insect within. 



