BLUE-GREEN CATERPILLARS 



405 



TABLE 1— Continued 



Matings giving a second generation 



1920-gl 



FEMALE 

 PARENT 



MALE 

 PARENT 



All blue-green 



Grass-green and 

 blue-green 



Both parents were blue-green as larvae. 

 Mated September 2. Few eggs laid, on 

 September 9, pure white, not cream 

 w^hite. The few laid were mostly 

 fertile. Female inactive and weather 

 conditions unfavorable to incite egg- 

 laying. She died September 27. 5 

 larvae, all blue-green, in hibernation. 



Both parents grass-green heterozygotes, 

 but the small brood of caterpillars 

 contained an excess of blue-green, viz., 

 6 blue-green and 2 grass-green (prob- 

 ably not all the grass-green larvae 

 were seen, though they were much in 

 excess of 25 per cent blue-green). 

 Caterpillars in hibernation. 



/S^cf was again mated with another 

 sister, /S-"? giving a large brood, e, 

 of grass-green larvae.^ Since this is 

 a DR X DD combination, inbreeding 

 next summer is expected to bring out 

 plenty of blue-green larvae. 



1 (Postscript, September, 192L) From this brood, e, during the summer 

 of 1921 blue-green caterjjillars were recovered, but. only by mating females of 

 6 to wild males and then inbreeding, as will be described in a later paper. 



[Note added September, 1921 : These facts regarding the inheri- 

 tance of blue-green have been amply supported by the experi- 

 ments of the following season (1921), when a new recessive 

 mutant caterpillar, olive in color, producing a butterfly with 

 olive-colored eyes, appeared in recovering the blue-green strain 

 from grass-green after back-crossing with wild stock.] 



VIGOR OF THE MUTANT CATERPILLARS 



The census of brood /3 as caterpillars, viz., 59 grass-green: 

 18 blue-green, was also perfectly definite and tends to show that 

 the blue-green larvae are stronger and more resistant to disease 



THE JOURNAL OP EXPERIMENTAL ZOOLOGY, VOL. 34, NO. 3 



