April, '14] O'KANE: INSECTARY CONSTRUCTION 181 



President P. J. Parrott: We observe this phenomenon with the 

 cabbage maggot. It will be necessar^^ to bring this discussion to a 

 close, and I will call for the next paper by Prof. W. C. O'Kane on 

 ''Further Experience with an Insectary." 



FURTHER EXPERIENCE WITH AN INSECTARY 



W. C. O'Kane, Durham, N. H. 



Five years ago we built an insectary at the New Hampshire Experi- 

 ment Station. The idea was to provide a permanent structure which 

 would afford natural conditions for life history work. 



The building Avas made 13 x 24 feet At one end is a wood struc- 

 ture 6 X 13 feet. This has solid walls and roof, two ordinary glass 

 windows and an entrance door. From it another door leads to the 

 open work-room. 



The latter is 13 x 18 feet. It was made with removable screen sides 

 set in a framework that could be taken down by removing bolts and 

 screw^s. The roof of this work-room was of canvas and was made 

 double, allowing air space between. 



The entire structure is carried on a concrete wall rising 18 inches 

 above the ground. In the small enclosed room a concrete floor ^was 

 laid. The larger open room was provided with a cement floor doA\Ti 

 the middle. On one side of this are six concrete pits and on the other a 

 strip of soil 2 feet wdde. This strip of soil as well as the dirt in the pits 

 is continuous with the ground beneath. A full description of the 

 building, and photographs of it, will be found in the Journal of 

 Economic Entomology, Vol. 2, page 389. 



Experience with this insectary has led naturally to the proof of 

 some advantages and the discovery of some disadvantages. The former 

 are as follows : 



The large, open work-room is an excellent place for carrying on some 

 kinds of experiments through the summer season, especially such as 

 require the use of small breeding cages. The temperature is the 

 normal of the air. Humidity is normal. The bins and the earth strip 

 provide fairly acceptable soil conditions, but not a normal amount of 

 moisture in the surface layer. 



In winter the frame work, screens and canvas top are removed. 

 The open structure has then been used for general storage of hibernat- 

 ing material. The earth in the bins and in the strip has been used for 

 earth storage. The closed section has served for storage under shelter. 



The disadvantages discovered have been as follows: 



For summer use the work-room can provide normal conditions 

 only as regards temperature and humidity of the air. We have found 



