MODIFICATION OF COLOR. 



175 



ing. Light, however, is a factor of no importance, as the colors are always 

 developed in the dark. The temperature records are as follows : 





Tabids 56. — Temperature conditions. 







Conditions— 



7 a. ra. 



I p. m. 



8 p. m. 



Maxi- 

 mum. 



Mini- 

 mum. 



Aver- 

 age. 



Deviation 



from 

 normal. 



In nature .... 

 In experiment. . 



° C. 

 19.2 



- 3-30 



° C. 



30.62 



0.5 



17.389 



- -5 



° C. 



+3 

 2 



° C. 

 -13 

 - 4.5 



22.403 

 — I.I 







-23.5 



In this experiment 92 per cent died in the larval and prepupal stages, 6 per 

 cent in the pupal, and 2 per cent, 20 males and 12 females, completed their 

 metamorphosis. The pupal period averaged 64 days, or more than six times 

 its duration in nature. The imagines were all strongly modified toward an 

 albinic appearance, having a pale yellow-white hypodermal color. The dark 

 color of the epicranium was wanting, as were also the spots h, d, e, and / on 

 the pronotum ; c and a were much reduced, and a was divided. On the elytra 

 the costal and anal stripes were wanting, and the others were reduced in size 

 and were lighter in color. Upon the ventral surface the legs were devoid of 

 color and only the outer sternal spots were found, and these only upon the 

 thoracic and the three or four anterior abdominal segments. The extreme 

 albinism of the beetles is apparent from the following seriations : 



Tabi,E S7' — General color of beetles used. 



Class 



2 



3 



4 



5 



6 



7 



8 



9 



10 



II 



12 



13 



Parents 



Control 



Experiment. . 



Ret. 



I 



Ret. 

 13 



Ret 

 43 



Ret. 



I 



I 



29 



Ret. 



2 



2 



13 



Ret. 



5 

 6 



I 



Ret. 

 20 

 22 



Ret. 

 42 

 28 



Ret. 

 18 

 25 



Ret. 

 9 

 9 



Ret. 

 2 

 5 



Ret. 



I 

 2 



Empirical mode of parents 9 



Empirical mode of control 9 



Empirical mode in experiment. ... 4 



Modal deviation of parents. , . . , 

 Modal deviation of control . . . . , 

 Modal deviation in experiment 



Between this experiment and experiment 3 there was a close similarity in 

 the mortality and modifications produced, and also in the fact that in both 

 any further decrease of average temperature was fatal to 100 per cent of the 

 beetles, so that as far as the development of color was concerned, experiments 

 3 and 7 attained to the highest limits at which color and color patterns could 

 be produced in these beetles without their being previously acclimatized to 

 higher or lower temperatures. 



In experiments i to 7, 40,700 larv« of decemlineata from Massachusetts, 

 Long Island, Ohio, and Illinois were used, and from these there emerged 

 13— T 



