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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



pots known to dealers as fern pots (PI. 4, fig. 6), for egg incubators but 

 the tin boxes (PL 4, fig. 7), have given us more uniform satisfaction. 



In order to study the habits of the grubs, their growth, molts, etc. 

 one-ounce tin salve boxes are employed (PI. 5, fig. 12). These are 

 filled with soil, moistened to the proper degree, the grubs placed 

 therein and a grain or two of wheat added. Extreme care is necessary 

 in handling the young grubs and they must be disturbed as little as 

 possible. Older grubs are fed grains of corn and are examined once a 

 week, fresh soil and corn being added as needed. For convenience in 

 handling we have trays (PI. 5, figs. 10 and 11), made to hold 60 or 

 70 tin boxes and just the depth of the boxes and these are fitted in 

 grooves, like the drawers of an insect cabinet, thus putting them in 

 compact form and in such shape that any individual drawer or tin 

 tray can be drawn out and examined without disturbing the others. 

 By use of a blue pencil, such as is designed for writing on china, tin, 

 etc., the cage number can be placed directly on the box and it will not 

 be erased except by vigorous rubbing. As winter approaches all of 

 the tin boxes are carefully examined to prepare the grubs for hiber- 

 nation. All grain and vegetation is removed and the soil properly 

 moistened. Watering, especially at this time of year, is an important 

 item, time and experience alone enabling one to judge; it suffices to 

 say that overwatering is the more natural and consequently to be 

 guarded against. After the boxes are prepared for winter they are 

 left in the tin trays which are placed one on top of the other, or are 

 placed in pasteboard boxes holding a half gross or more, and buried in 

 a compost heap to the depth of from one to two feet (PL 5, fig. 8). 



The tin boxes above described are invaluable for many purposes. 

 Grubs received from different localities and situations are reared in 

 them with very little effort. When filled with sphagnum moss they 

 make excellent receptacles for sending living grubs and other insects 

 liable to injury in shipment. The past summer we successfully em- 

 ployed them for obtaining molts, length of instars, amounts of foliage 

 eaten during different instars, etc., of the army worm (Heliophila 

 unipuncta), one-ounce size being used up to the fifth molt, after which 

 three-ounce boxes were used. They are simple, cheap, easily handled, 

 and the molts readily determined, enabling us to run an extensive 

 series of individuals. It is scarcely necessary to say that in the case 

 of the army worm, check experiments were run to determine whether 

 or not the tin boxes produced unnatural conditions for the larvae, and 

 in this case they did not, larvae in the tins behaving, feeding and molt- 

 ing as did larvae in several other kinds of cages. From our experience 

 with tin boxes they are the simplest breeding cages available and, 

 considering everything, will prove to be as invaluable to the entomolo- 

 gist as to the salve doctor. 



