EXPERIMENTS WITH CHRYSOMELID BEETLES. 25 



TABLE V. 

 THE WEIGHT OF INDIVIDUAL LARV. OF Calligrapha bigsbyana WHEN 7 DAYS OLD; 



J'-ST AFTER THE FlRST MOL'LT. 

 M'lulting. j -it in mgs. 



July 16 5.8 



Jul- 5.4 



Jul> 5-4 



July 17 4.8 



July 17 4-6 



Jul 4- 



Jul 2.6 



Jul- 2. 

 July P, .9 



days. l-'roin tin- 1. ittcr tinn- onuard the larva? gradually cease 



ling .nnl lie on their l>a<k- in the earth provided for them. 



1 hiring thi- |>re|.,ir,it \< >n for |ii|iat ion, and during the period of 



|iii|i.iiioii. there i- a -tead\ dediiu- in weight until the adults 



emerge. 



I i. 1 . 2 -h<>\\- the daily pen vnta^e increments in the \\eiijit of 

 the de\elopin;c beetle-. The remarks made in explanation of 

 I . . I .iUo explain the irre^ularit ie- in this curve. The percent- 

 age increment- decline very rapidly during the moulting period-. 

 It all of the l.ii\.e moulted .it the -umc time, the rate \\mild he 



iti\ e. 



The dat.i obtained fri'in the-e uei^hiir^- conl'irin \\hat Miimt 

 [891, l '107 h.i- found to l.e true of miinea-piy;-, i. e., the rate of 

 Drouth decline- rapidl\ during the early ^-t.i^e- of dexelojunent 

 and more -lo\\l\ during the later stages. jYnkin-oii I')'") has 

 ohtained -imilar n-iilt- for many other animal- l.y u-ini; the 

 data alreadx a\ailaMe in literature. 



II. Tin 1 'MM i- MI- LIMIT UPON Tin I >HVELOPMI-:N r OF 



I. The Influence of Darkness. 



Method and l\it<i. l-".\|K-riinent C.B. 42. Kight eggs of C. 

 hi^/'yaiui \\en- laid at \2 M., June 10. Four were allowed to 

 de\elop in an ordinal \ -lender di-h (7 cm. in diameter), and the 

 other four were placed in a >imilar receptacle which had been 

 covered externally \\ith a coat of opaque paint. The same 

 amount of moi-ture was -upplied to each dish, and the tempera- 

 ture did not vary a d< gr< e. 



