M \l -Inl'Ml \l AND DURATION" OF I.IFK IX INsl-XTS. 3 



mortality of the -tarved caterpillars ought not to be ascribed 

 first of all to the emaciating influence of inanition, the chief cause 

 of tin- mortality i- tin- moult. Directly after moulting tin- animal 

 take- very much food, as during these processes it dor- not eat 

 at all and only digests its own substances. Then-fore when the 

 fa-tin^; day falls on the period succeeding moult tin- caterpillars 

 an- often unable to resist starvation. The mortality of chry-alid-. 

 on the contrary, was identical in starved and in control specimens. 

 The willow leaves on which the caterpillars were fed were al\va\ - 

 of the same variety and of the same freshness. The conditions 

 of space, light and moisture were identical in all jars during tin 

 whole t me of observations and the temperature was from 16 

 to 19 ('. Food was put in great superfluity into control jars 

 e\ery morning and into those containing starved material during 

 iht feeding days and it preserved its freshness the whole day. 

 All experiments were performed during one season (1920). 



i. Tin-: iNFi.t'KNCK OF IN AM i ION ON i HI: Di RATION OF SKPA- 

 i< \ 1 1 1 >i \ i i i r\i i N i A i. Si A<;I-:S. 



lor the experiments of series A caterpillars belonging to four 

 dillt-n-nt broods were used, from I to o hours after hatching, 

 These caterpillars wen- deprived of food every second day, in 

 the remaining days they were fed ad libitum. Starvation la-iiiu 

 one day and applied every second day may be designated by ilu- 



-\mbol + + - H Table II. records the limits of individual 



fluctuations in the duration of life of the caterpillars and chrysa- 

 lid- belonging to each brood, as well as the average duration of 

 lite in -i arved and in control specimens of the t\\o -e\e-. Table 

 III. finally shows the average differences of the duration of 

 larval and of pupal life of individual- deprived of fond for each 

 brood separately, calculated in penvir . t the average dura- 

 tion of the larval oj of the pupal stage- "I control specimens of 

 the same brood and the same sex. From the-e tables we see that 

 the life of caterpillars subjected io-n.!i -iai \ation was considera- 

 bly prolonged. In all lots \\ithoiii exception the longest-lived 

 control caterpillars underwent pupation earlier than theshortest- 

 lixed starved specimen- < f tin- -aim- brood and sex. (Cf. Table 

 I I . Series A). It we take the a\ era^e >\ the averages of all broods 

 of >eries .1, a quantity which I -hall call "average of brood-." 



