OBSERVATIONS ON LARV.E OF CORETHRA PUNCTIPENNIS. 283 



Table IV. The higher average of dry matter in the June material 

 may be due to a larger proportion of chitin in the larvae just 

 before they pupate. In August and early September the average 

 size of the larvae seems to be smaller than that of the winter brood 

 and this is confirmed by the weights. At the height of the 

 pupating season the summer larvae pupate when they are distinctly 

 smaller than the individuals which live over winter. The live 

 weights of the smaller lots were also determined, as shown in 

 Table IV., and they indicate that about 91 per cent, of the living 

 animal consists of water. 



The live weight of the June pupa? was only about n per cent, 

 larger than that of the June larvae, but the dry weight of the 

 former was nearly twice as large as that of the latter. (See 

 Table IV.) This marked difference in the dry weight was prob- 

 ably due to the presence of a larger amount of chitin in the pupa. 



TABLE IV. 



THE AVERAGE WEIGHT OF A SINGLE INDIVIDUAL OF CORETHRA PUNCTIPENNIS IN 

 MILLIGRAMS, TOGETHER WITH THE PERCENTAGES OF WATER AND OF ASH. 



The adults yielded a much smaller live weight than either the 

 larvae or the pupae because they possessed a much smaller propor- 

 tion of water. Their dry weight was greater than that of the 

 larvae but smaller than that of the pupae. The adults used for 

 this weight were obtained from a large swarm on June 29, 1918, 

 when pupation was very active, but there was no means of ascer- 

 taining their age ; their weight probably decreases somewhat with 

 age, and they live for a period of three to five days. 



The ash of the larvae varied from a minimum of about 7 per 



