August, '081 JOURNAL OF ECONOMIC ENTOMOLOGY 267 



ments, before we shall have a knowledge of the fundamental princi- 

 ples which will enable us to attain the best results. Such an investi- 

 gation has already been begun at the Massachusetts Experiment Sta- 

 tion with the anticipation that five or ten year's work may give re- 

 sults which will help place spraying on a firm and scientific basis. 



DESCRIPTION OF NEW DEVICES FOR REARING 



INSECTS 



By A. F. Blugess. WaHhingtoii. D. C. 



One of the serious problems which it was necessary to solve in 

 order to successfully rear the parasitic and predaceous insects which 

 were being shipped from Europe to prey on the gypsy and brown-tail 

 moths was to secure apparatus by means of which these insects, as 

 well as their hosts, could be successfully reared in large numbers. 

 All of the old style equipment in general use hy entomologists for 

 rearing work was tested, but in 'many cases it was found that radical 

 improvements were necessary in order to accomplish the results de- 

 sired. It was of primary importance to place the insects under as 

 nearly as possible natural conditions and at the same time to keep 

 them in confinement where they could be studied and observed and 

 not allowed to escape from captivity. The purpose of this paper 

 is to call the attention of working entomologists and others who may 

 be interested in rearing insects to several devices which are now in 

 use at the Gypsy Moth Parasite Laboratory, Melrose Highlands, 

 Mass., and which have been found to meet some of the serious defects 

 of the equipment that is in general use in insectaries and insect-breed- 

 ing laboratories. 



The most important of these is a tray for rearing insects which 

 was devised by Mr. W. F. Fiske of the Bureau of Entomology. Wash- 

 ington, D. C, who is in charge of the Parasite Laboratory. It is illus- 

 trated in PI. 3, Figs. 1 and 2. The standard size used at the labor- 

 atory is 14 in. square and 3 in. high. The bottom is covered with 

 cheese-cloth which is attached by paste to the sides of the tray. With 

 the exception of a 2-in. rim around the upper edge, the top is open ; 

 while directly beneath this rim a band of sticky Tanglefoot is placed in 

 order to prevent the escape of the insects. This band is applied before 

 the cheese-cloth bottom is attached and it is a simple matter to re- 

 place the bottom with a new^ piece of cheese-cloth when desired. The 

 tray is built of one half inch white wood stock and the joints are se- 

 curely nailed ancf glued in order to make it tight. A modification 



