318 SETTING AXn IT.ESEUVING INSECTS. 



INSECTS. 



Entomologists are generally satisfied if they can obtain the insect 

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

 tion of tlie egg, larva, and ])U[)a may induce the collector to enrich 

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

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

 culars for this jiurpose. 



Tlic Eixg. — ^The eggs of most insects retain their form and colour 

 well if preserved in the cabinet; but those viliicli do not })romisc fairly 

 rnay be i>repared after the method practised by Swamnierdam. lie 

 used to pierce the eggs with a very fine ndedlc, and ])ress all the con- 

 tained juices through the apertm-e: he then iniluted them until they 

 reo-ained their ])roper fi)rm by means of a small glass tulie; and 

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

 solved. 



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

 is not only one of the most curicjus, 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 

 and transparency of the parts are retained, and are preserved for a 

 length of time in this liquid. 



In the cabinet of Mr. William Weatlierhead are preserved many 

 larva; of the Lqndoptcra, 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 punctiu-e in the tail, and very gently 

 pressing out all the contained humours, fills the skin with very fine 

 dry sand; the insect is thus again brought to its natural shape: in the 

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

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

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

 is another method which is treciuently 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 stanchng posi- 

 tion : it may aft( rwards be anointed with oil of spike in which some 

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



Tlic Pupu. — Wiien insects have quitted the pupa st;ite, the case will 

 require only to be put into the drawers; biit those which have insects 

 within must be' either drop.ped into scalding water, or inclosed in a 

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

 kill the insect wiihin. 



