I9S 



COLORATION IN LEPTINOTARSA. 



Experiment 25. — To determine the effects of a large average increase in temperature 

 and moisture upon the coloration of L. decemlineata. 



Conditions. — Temperature 13° C. and relative humidity 26 per cent above 

 that in nature, with other conditions normal. 



Apparatus. — The same as in experiment 23. 



In this series of experiments, which was conducted during the years 1901 

 to 1904, 2,500 larvae were used, which were hatched from_ 4,500 eggs placed 

 under the conditions of experiment soon after being laid. The conditions of 

 experimentation were as follows : 



TabIvE 92. — Temperature and humidity conditions. 





7 a. m. 



10 a. m. 



I p. m. 



3P-m- 



8 p. m . 



Maxi- 

 mum. 



Mini- 

 mum. 



Aver- 

 age. 



Deviation 



from 



uormal. 



Temperature, dry bulb: 

 In nature 



19 

 28 



Per ct. 



*IOO 

 *IOO 



° C. 

 22 



35 

 Per ct. 



65 

 *I0O 



° C. 



30 

 45 



Per ct. 



50 

 100 



24 

 38 



Per ct. 



55 

 *ICX) 



° C. 



22 



30 

 Per ct. 



*IOO 

 *IOO 



° C. 



33 

 47 



Per ct. 



100 

 100 



° C. 



13 

 25 



Per ct. 



43 

 100 



22.2 



35-2 



Per ct. 



74 

 100 



° C. 





 + 13 

 Per ct. 







+ 26 



In experiment 



Relative humidity: 

 In nature 



In experiment 



*Dew. 



In this series of experiments 56 per cent died in the larval stage, 39 per cent 

 in the pupal, and 5 per cent, or 125 individuals, emerged, of which 70 were 

 males and 55 females. 



The larval colors were modified as in experiment 24, only to a much greater 

 extent. The imaginal coloration was strongly albinic, being almost the dupli- 

 cate of that found in experiments 3, 7, and 18. The beetles were all small, 40 

 per cent below standard size, and light colored. The dark markings were all 

 brown, no black being visible in any part. The strong albinic tendency is 

 shown in the following seriations : 





Table 93. — General color 



of beetles used. 









Class 



I 



2 



3 



4 



5 



6 



7 



8 

 P.ct. 



9 

 F.ci. 



10 

 P.ct. 



II 



P.ct. 



12 

 P.ct. 



13 

 P. a. 





P.ct. 



P.ct. 



P.ct. 



P.ct. 



P.ct. 



P.ct. 



P.ct. 



Parents 











I 



2 



5 



20 



42 



18 





2 





Control 









. . 



2 



7 



8 



17 



37 



iq 



8 



I 



I 



Experiment*. 



I 



20 



64 



19 



II 



8 



2 















Individuals = 125. 



Empirical mode of parents 9 



Empirical mode of control 9 



Empirical mode in experiment. ... 3 



Modal deviation of parents.. o 



Modal deviation of control o 



Modal deviation in experiment —6 



