530 proceedings: entomological society 



ments in constructing insectaries at the Eastern Field Station of the 

 Bureau of Entomology. It is important to confine the work done in an 

 insectary to one type of rearing or to rearing of insects of one order. 

 The cone type roof with broad eaves is much more satisfactory than 

 any other type used. Illustrations and blue print plans of the insec- 

 taries of the Eastern Field Station were exhibited. The use of hinged 

 wooded doors to afford protection and permit changes in ventilation 

 was emphasized. It was pointed out that such means of protection 

 is much more satisfactory^ than canvas curtains. Graphs showing how 

 the temperature of an insectary protected by canvas curtains departed 

 from the temperature of the surrounding air and varied much more 

 than that of an insectary protected with wooden doors were presented. 

 These graphs showed that even under the most favorable conditions of 

 ventilation the temperature of the insectary protected with canvas 

 curtains showed an unusual range and often departed as much as 

 15 degrees F. from the surrounding air. This forces the conclusion 

 that unless it is possible to be at hand continually and alter the canvas 

 curtains the use of canvas in the construction of insectaries is unsatis- 

 factory. Mention was made of the value of a vestibule entrance for 

 insectaries containing exotic insects, and also of the use of a dark 

 room, with only one source of light, in removing insects from cages. 

 It was recommended that an effort be made to standardize insectaries 

 and that they be built on the sectional basis. 



In discussing the preceding papers on rearing cages and devices, 

 Mr. RoHWER called attention to the apparent differences in opinion 

 between the previous speakers. One speaker had stated that he had 

 better success under most artificial conditions; another speaker had 

 emphasized the great importance of duplicating natural conditions; 

 another had implied that humidity had but little effect. From the 

 standpoint of the taxonomist it seems to be of great importance to 

 know under what condition material was reared because there seems 

 to be more variation in color in reared hymenoptera than in collected. 

 The only way to explain this great variation in some forms is to assume 

 that there was a difference in conditions under which they were reared. 

 We know from experiments on Lepidoptera that melanistic or albinistic 

 races can be produced by changing humidity. It is therefore only fair 

 to the taxonomists that records of the kind of rearing devices and 

 approximation of natural conditions be recorded. 



Dr. QuAiNTANCE described briefly the ingenious device perfected by 

 Mr. R. L. Nougaret for the study of the grape phylloxera in California. 

 The vines are planted in two large flower pots, one above the other and 

 the whole placed in a deep pit. When it is necessary to examine the 

 colonies of phylloxera the pots are raised out of the pit by means of a 

 derrick. Tvlr. Heinrich emphasized the necessity of having the food 

 furnished to larvae in its natural condition, citing the formation of 

 poison in the leaves of wild cherry after they are picked. Mr. Greene 

 stated that to rear diptera successfully natural conditions must be 

 maintained. R. A. Cushman, Recording Secretary. 



