THE STUDY OF ENTOMOLOGY 219 



If the student should wish to preserve any of the 



insects for future reference he 



Preservation. should, when collecting, drop 



them into a tube containing 

 what I call the collecting fluid, consisting of one part 

 rectified spirits of wine, two parts 2 per cent formalin, 

 and as many crystals of menthol as it will dissolve. 

 This solution requires filtering before use. As soon 

 as they are dead and have sunk in the collecting fluid 

 they are transferred to the permanent preserving fluid, 

 which is 2 per cent formalin. What is called 2 per 

 cent formalin is made by adding i oz. of formalin to 

 19 oz. of water and filtering. It is an inaccuracy to 

 call this a 2 per cent formalin solution, as it is in fact 

 a 2 per cent solution of formic aldehyde. Formalin 

 is the trade name given to a 40 per cent aqueous 

 solution of formic aldehyde. 



Entomologists generally collect and kill insects in 

 an ordinary cyanide bottle, and pin or gum them on 

 to cards after relaxing and arranging their parts. 

 These are stored in boxes and cabinets, and kept for 

 study and examination. Such insects as Trichoptera 

 can be treated in this way, but the delicate Ephe- 

 meridse become disintegrated in a very short time. 



A sub-committee was formed some years ago of 



members of the Fly-Fishers' 



Collection at the Fly- Club to collect and preserve 



Fishers' Club. the insects which are of special 



interest to all fly-fishermen. 

 Most of the early specimens were collected and 



