24 ROBERT \V. HKGNER. 



Davenport (1897) has shown for the tadpoles of Rana, Bnfo 

 and Amblystoma, that, during the first two weeks of larval life, 

 growth is largely due to the absorption of water, which increased 

 from 56 to 96 per cent. During later development, however, the 

 storing up of formed substances is mainly accountable for their 

 growth. The curve of the growth-rate for tadpoles does not 

 agree with the general rule; it rises first, then declines, and 

 finally rises again. This result is probably due to the absorption 

 of water. 



TABLE IV. 

 THE RATE OF GROWTH OF LARV^: OF Telea polyphemus (TROUVELOT, 1867). 



Trouvelot (1867) has given a few weighings of the larva? of the 

 moth, Telea polyphemus. These have been arranged in Table IV. 

 so as to show the actual increase in weight, and also the percen- 

 tage increments for ten day intervals. The decline in the rate 

 of growth is not regular, probably because of the meager data, 

 but it is no doubt similar to that exhibited by the guinea-pig and 

 other animals. 



Fig. I shows the weight of developing beetles of the species 

 C. bigsbyana from the time of hatching to the emergence of the 

 adults, a period of 33 days. The following data will make clear 

 certain irregularities in the curve. The larva? usually devour a 

 part or all of their cast-off egg-shells soon after hatching, but do 

 not begin to feed actively until the second day; this accounts for 

 the very slight increase in weight during the first two days. An 

 actual decrease in weight \\ould be expected at the moulting 

 periods, when food-taking ceases and tin- rhitinous covering is 

 shed, but all larva? do not moult at the same time (see Table V.). 

 and instead of a decrease in the average \\cight, there is a slight 

 increase. This is shown in all of tin- moults. The period of 

 most rapifl increase is that I >n \\rcn the fifth and the fifteenth 



