pedigre:e bree;ding. 



279 



all, excepting one, unable to breed successfully with decemlineata, and I have 

 never had both sexes of melaniciim from nature at the same time. 



In June, 1902, I found a male melaniciim and a female decemlineata in 

 copulation, which were at once transferred to the vivarium, where they 

 gave a hybrid generation of 14 adult beetles, with the decemlineata char- 

 acters dominant. These 14 beetles, 6 male and 8 female, were bred inter se, 

 and, while relatively infertile, gave in the second generation 36 beetles, 10 of 

 pure melaniciim and 26 of decemlineata type. The entire lot now went into 

 hibernation, but were all killed during the winter of 1 902-^03 by a freeze. 

 The series, short and incomplete as it is, shows that melanicum behaves in 

 crossing exactly as does pallida. At other times I have made crossings of 

 melanicum and decemlineata, but without result; although copulation was 



^GENERATION S, 



I 



II 



III 



IV 



V 



VI 



VTI 



Parents, original cross of 1 $ PALLIDA X 3 9 DECEMLINEATA 



Y 

 HYBRIDS (decemlineata dominant) 



DECEMLINEATA 

 31, 



29^ 

 DECEMLINEATA 



DECEMLINEATA 

 339 



DECEMLINEATA 

 31 (? , 40 9 



PALLIDA 

 6 



DECEMLINEATA fPALLIDA 

 17^>^6 9 [4^, 69 



PALLIDA 

 11^.,89 



PALLIDA 

 46^,144 9 



PALLIDA 

 33^,1419 



PALLIDA 

 56^, 50 9 



i 

 PALLIDA 

 96<J,|96 9 



PALLIDA 

 43 $, 30 9 



Text-figure 20. 



usually observed, fertile eggs were not produced. This variation is evidently 

 much more isolated from its parent species than pallida, and has also much 

 more remote chances of gaining a foothold in nature under ordinary condi- 

 tions. Extraordinary conditions wherein there arise a large number of 

 melanicum might give it a start, but such conditions do not seem to have been 

 realized in nature. It is, moreover, ill adapted to the habitat of decemlineata, 

 into which it must be born, as it is apparently able to live or reproduce 

 only in a high percentage of humidity. My experience with them is that 

 only the above condition can be used for their propagation in experiment, 

 and there is every reason to believe they would require a like condition in 

 nature. 



A variation resembling melanicum, but differing from it in having the 

 whole surface closely set with minute black dots and the color marking in 

 general irregular, occurs rarely, only two specimens of it ever having come 

 into my possession. Both of these specimens were females and were found 



