[95] COLLECTING AND PRESERVING INSECTS EILEY. 



Dissolve 100 grains alum, 25 grams common salt, 12 grams saltpeter^ 

 60 grams potasli, 10 grams arsenious acid in 3,000 grams boiling water. 

 Filter the solution, and when cold add 10 liters of the liquid to 4 liters, 

 of glycerin and 1 liter of methyl alcohol. 



LABELING SPECIMENS. 



General Directions. — It matters little how much care and pains have 

 been taken in the preparation and mounting of specimens, they will 

 have little value unless accompanied by proper labels giving informa- 

 tion as to locality and date of collection, name of collector, and a label 

 or number referring to notebooks, if any biological or other facts con- 

 cerning them have been ascertained. There should be pinned to the 

 specimen labels referring to, or giving all the information obtainable 

 or of interest concerning it. A somewhat different style of label will 

 be found necessary in the case of the two forms of collections described 

 in the foregoing pages, namely, the biological or economic collection, 

 and the systematic collection. For the former, numbers may be 

 attached to the specimens which will refer to the notes relating to the 

 specimen or species. For the latter, in most cases, all necessary infor- 

 mation may be recorded and made available by written or printed 

 labels attached directly to the specimens. In most cases, however, I 

 find a combination of these two systems convenient and desirable. The 

 numbering system is very simple, and is the one which I have followed 

 in all the species for which I have biological or other notes. It consists 

 in giving each species, as it comes under observation, a serial number 

 which refers to a record in a notebook. With this number may be 

 combined, if convenient, the date of rearing or collection of the speci- 

 men, and also the locality and food-plant if known. The vast number 

 of species represented in a systematic collection renders the numbering^ 

 system entirely out of place and inadequate, and the labeling system 

 alone is generally available. If it becomes necessary in the systematic 

 collection to refer to food-plants or life-history or any other fact of 

 interest, the numbering system should be used, and I recommend that 

 the numbers be written in red ink on the labels, to distinguish at a 

 glance the numbers referring to biological notes from other numbers 

 that will occur in the collection. 



Labels for ][)inned Specimens. — The following labels should be em- 

 ployed in the collection : (1) Locality label, which should be as explicit 

 as possible. (2) Date of capture, which is very usefnl and sometimes 

 quite important in various ways. It indicates at what time additional 

 specimens of some rare species may be secured, and greatly assists in 

 elaborating the life history of the species, and in other cases assists in 

 the correct determination of closely allied insects, which differ chiefly 

 in habit or date of appearance. (3) A label to indicate the sex. This 

 label has recently acquired greater importance than formerly, on ac- 

 count of the value of the sexual differences in the distinction of 



