June, '09] ENTOMOLOGICAL NEWS. 257 



measurements and should be kept as checks on the alcoholic 

 aphids, which may shrink a little. 



After a comparative test of nearly two years I cannot see 

 that the addition of a little glycerine to the formalin has kept 

 the appendages any more flexible than has 2^ per cent, 

 formalin. The glycerine may delay the hardening effect a 

 , little while, but as a permanent preservative does not seem 

 superior to formalin alone, and is not likely to be so clean. 



If special study is given to a species, it is well to fix some 

 specimens in water at about 80 degrees C. then leave them 

 several hours in 35 per cent, alcohol before transferring them 

 to 70 per cent, for permanent preservation. As soon as suf- 

 ficiently hardened they should be pricked. Such material is 

 excellent for the study of some structures that might ordinar- 

 ily be retracted, since the bodies remain very plump and the 

 abdomens are slightly distended. 



I like to keep my unmounted collection, for the most part, 

 in i dram homeopathic vials, because the specimens are so 

 easily accessible with a wide-mouthed pipette or forceps. 

 Smaller vials than I dram do not have sufficient capacity for 

 more than a very few specimens and, if round-bottomed, are 

 a constant annoyance. 



When sent in fluids by mail the insects are liable to be re- 

 ceived devoid of the normal number of appendages and are 

 almost as unfit for determination as aphids sent, like so many 

 flowers, in a letter. The best way to mail specimens in fluids 

 is to crowd them securely in place with a wad of lens paper. 

 Space can be allowed for the labels above the paper. Other 

 things then being equal the insects will reach their destination 

 in good shape. Cotton is not so useful as lens paper because 

 the appendages will be entangled with the fibers. 



It is necessary to mount plant lice for detailed study with 

 a compound microscope. To secure good mounts with little 

 or no shrinkage, specimens taken from the stock collection in 

 70 per cent, alcohol, are first pricked in the abdomen to secure 

 thorough dehydration ; they are then transferred to 05 per 

 cent, for several hours, and are next placed in absolute to 



