PEOCEEDI^■GS OF THE THIRD ENTOMOLOGICAL MEETING D).! 



aud down the inside of the abdomen, to prevent the latter from breaking 

 off, as dragon-flies when dried are peculiarly brittle objects. 



Wet material. Many insects are not easily preserved dry, either 

 because they are too small to pin or because they shrivel up. Minute 

 insects (such as small Chalcidids), which in any case require to be mounted 

 as microscopic objects for satisfactory study, are best pre- 

 served in spirit. Spirit is also the best medium for the collec- 

 tion and preservation of insects such as Aptera generally, termites, 

 Embiads, Thysanoptera, and Aphids, which shrivel up too much to 

 make satisfactory dry specimens ; and it is also as well to preserve 

 in spirit some duplicate specimens of most other groups which are 

 ordinarily pinned, in order that both wet and dry examples may be 

 available for study, this remark applying especially to such groups as 

 Psocids, earwigs and dragon-flies. Some insects whose brilliant 

 colours in life are due to a thin film of liquid within the chitinous 

 epidermis, such as many CassidLne beetles, lose these brilliant colours 

 entirely when dry, but the brilliancy is retained in the case of specimens 

 kept in spirit or formalin and in such cases a few duplicate examples 

 may be kept wet. Immature stages are also best placed into spirit. 



The best preservative agent for general use is ordinary spirits of 

 wine at a strength of about 70, reduced to about 50 in the case 

 of immature and very soft-bodied insects so as to avoid distortion. 

 Formalin is also used sometimes but is not very satisfactory ; 

 the ordinary commercial formalin is of about 40 per cent, strength aud 

 this is diluted to about 4 per cent, for preserving purposes. 



For collecting, therefore, a supply of corked tubes of various sizes 

 and filled with spirit is required, and a pencil and paper should also be 

 at hand in order that a temporary label may be placed in each tube as 

 it is filled. These temporary labels should be replaced or supplemented 

 by permanent labels, giving full data and written on good paper with 

 a moderately soft pencil, and placed inside each tube. Labek stuck 

 onto the outside of tubes are liable to fall off or be obUterated. 



A collecting-hag is a useful accessary in which to carry the 

 apparatus required for fieldwork. It may be of any convenient size or 

 material. A very useful bag is easily and cheaply made from stout 

 cloth or light canvas about sixteen inches broad and twelve deep and 

 three wide, with slightly rounded corners, and provided with a flap 

 secured by a button and also with a wide strap to pass over the 

 shoulder. The bag may be divided into two or more compartments 

 in order to avoid mixing full and empty boxes, tubes, etc. Such a 

 bag will hold killing-bottle, folding-net, field-knife, and a supply of 

 boxes and tubes. (Plate 154. fig. 1). 



