June, '22 mccolloch: length larval stage of cadelle 243 



in nature, yet the variation was hardly sufficient to cause this difference. 

 The temperature conditions were in close accord with those encountered 

 in many of the places infested by this insect. The food was the same 

 as would be obtained in the ordinary farm granary except that other 

 grain -infesting insects were not present. It is a well known fact that 

 the Cadelle is also carnivorous, feeding on the various stages of other 

 stored grain insects, and it m.ay be that these are essential. The fact 

 that many of the larvae lived two and three years, during which time 

 they were feeding, growing, and molting would indicate that the rearing 

 conditions were favorable. The high mortality after two or three 

 years is probably due to unsuitable conditions for pupation. Herrick^ 

 (p. 233) records pupation occurring in pine boards, while others state 

 that the larvae crawl into cracks and other sheltered places before 

 transforming. Further experiments are now under way or soon to be 

 started for the pirrpose of obtaining more data on the life economy of 

 this insect and the factors which influence larval developm.ent. 



Mr. E. p. Felt: May I ask if these larvae were kept with a fairly 

 good supply of food, or was it reduced to pretty near a minimum. 



Mr. J. W. McCoLLOCH : They were confined in individual salve boxes 

 filled with food, and this was changed frequently so that if they were 

 feeding on grain alone they obtained plenty. They were usually given 

 both wheat and bran in the same box, and in some cases some flour was 

 added also, and in a few cases we tried to rear them, entirely with flour 

 and grain; but we got the best results with wheat and wheat bran. 



Mr. Glenn W. Herrick: Do you give them much m.jisture? 



Mr. J. W. McColloch: Fairly dry. 



Mr. Glenn W. Herrick: I have a student carrying on experim.ents 

 feeding these larvae, watching the gain and growth, and he finds that 

 they desire a great deal of moisture. 



Mr. J. W. McColloch: We have had this experiment going on for 

 3 or 4 years. In the last two years we have had very dry weather, and 

 they lived in an open granary. 



Adjournment: 5.00 p. m. 



^Op. Cit. 



