PRESERVING INSECTS. 231 



gummed thickly a space on your card-board equal to, at 

 least, the entire specimen when expanded, place the beetle 

 upon it, drag out the limbs with a pin, and, leaving it to dry, 

 go on with the next one that presents itself. As the card 

 has to be cut afterwards around your insect (so as to suit 

 it), there is no advantage in gumming it precisely straight 

 upon your frame, though it is true that a certain amount 

 of care in this respect lessens your after-labor of cutting off 

 very materially. When your frame has been filled, and you 

 are desirous of separating the species, cut out the insects 

 with finely-pointed scissors. " 



For mending broken insects, i.e., gumming on legs and 

 antennas which have fallen off, inspissated ox-gall, softened 

 with a little water, is the best gum. 



For gumming insects upon cards, Mr. Wollaston recom- 

 mends a gum " composed of three parts of tragacanth to 

 one of Arabic, both in powder; to be mixed in water con- 

 taining a grain of corrosive sublimate, without which it 

 will not keep, until of a consistency just thick enough to 

 run. As the gum is of an extremely absorbent nature, 

 nearly a fortnight is required before it can be properly 

 made. The best plan is to keep adding a little water, and 

 stirring it every few days, until it is of the proper con- 

 sistency. It is advisable to dissolve the grain of corrosive 

 sublimate in the water which is poured first upon the gum. 



Preservative Fluids. The best for common use is alco- 

 hol, at first diluted with as much water; or weak whiskey, 

 as alcohol of full strength is too strong for caterpillars, 

 etc., since it shrivels them up. The spirits should after- 

 wards be changed" for alcohol of full strength for permanent 

 preservation. Glycerine is excellent for preserving the 

 colors of caterpillars, though the internal parts decay some- 

 what, and the specimen is apt to fall to pieces on being 

 roughly handled. 



Laboulbene recommends, for the preservation of insects 

 in a fresh state, plunging them in a preservative fluid con- 

 sisting of alcohol with an excess of arsenic acid in frag- 



