242 ENTOMOLOG Y. 



into whiskey, and then into alcohol. If placed in the latter 

 first, they shrivel and become distorted. Mr. E. Burgess 

 preserves caterpillars with the colors unchanged, by im- 

 mersing them in boiling water thirty or forty seconds, and 

 then placing them in equal parts of alcohol and water. It is 

 well to collect larvae and pupae indiscriminately, even if we 

 do not know their adult forms; we can approximate to them, 

 and in some cases tell very exactly what they must be. 



Rearing Aquatic Larvje. 



Many insects pass their early stages in brooks or ponds. 

 They can be dredged with the water-net, and reared in pans 

 or jars of water in which a few water-cresses, mosses, or 

 other aquatic plants may be kept to oxydize the water and 

 keep it pure. In this way the larvae or nymphs of Perlidae, 

 may-flies, dragon-flies, caddis-flies, aquatic beetles, Diptera, 

 and moths may be reared with more or less success. By 

 collecting such larvae in March, April, and May, a good 

 many species may be brought to maturity within a few 

 weeks' time. 



Any glass jar, or even a deep earthen pan, may suffice for 

 an aquarium, in place of more elaborate glass and iron struc- 

 tures. 



Mr. Lugger has invented an aquarium which he finds 

 very convenient for rearing aquatic insects; it consists of a 

 tin box one foot square in front and about three inches 

 thick, with a glass front. Over this glass front slips a 

 round-oval picture-frame. If the inside is painted and 

 filled with water, the whole looks like a suspended picture 

 of rather unusual thickness. Several such aquaria can be 

 grouped together like so many pictures. If connected by 

 siphons carefully graded, a constant ilow of water can be 

 obtained, which produces the necessary current and sup- 

 strong compression of the alcohol, which tends to force the cork out. 

 See Dr. Hagen on the use of rubber stoppers, Can. Ent., xviii. p. 1, 



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