110 Some Experiments with a PolijmorpMc Phasmid 



19 yellow $s, numbers which are difficult to reconcile with the 

 hypothesis. The most probable cross is MFEhcc x MMhhCc which 

 ought to have given equal numbers of each class. 



Brood 6. A horned green % of brood 1 parthenogenetically gave 

 approximately equal numbers of horned and hornless green $ s. The 

 parent was evidently heterozygous for H and the offspring would 

 presumably be MFHhcc and MFhhcc. 



Broods 7 a7id 8 are only of interest as showing that horns can be 

 introduced by the male parent. 



Brood 9. A horned yellow $ of brood 1 by a (/* of the same brood 

 gave 22 horned $ s and 29 hornless, while as regards colour there were 

 10 green $s to 41 yellow. 



The cross which would give the nearest result to this would be a 

 ? MFHliCc by a (/* MMhhCc giving equal numbers of horned and 

 hornless % s and green $ s to yellow $ s in the ratio 1 : 3. 



Brood 10. A horned yellow J of brood 1 by a </ of brood 1 gave 

 21 horned Js to 3 hornless, and 18 yellow Js to 6 green. This is 

 another doubtful brood, but the most probable cross to have produced 

 it is MFHhCc x MMHhCc, giving 3 horned to 1 hornless and 3 yellow, 

 1 green. 



Broods 2 and 11. In brood 2 a hornless yellow $ gave an F^ 

 containing only hornless yellow $s but in brood 11, the F.^ generation, 

 both hornless yellow and hornless green Js appeared — 12 green, 

 43 yellow. The first cross may have been either MFhhCc x MMhhCG, 

 or MFhhCQ x MMhhCc, and in either case the F^ contained individuals 

 of constitution MFhhCc and MMhhCc, which if paired would give 3 

 yellow $s, 1 green J. 



As a whole it is evident that the numbers realised in the experi- 

 ments do not agree well with those demanded by the hypothesis, but 

 in this connection it is necessary to point out that there was a very 

 high mortality during the early stages of the insect's life, which might 

 easily have disturbed the relative numbers, in which the various forms 

 of J occurred. It is hoped however that further experiments will be 

 made with the species and the results, especially those to be obtained 

 from broods produced parthenogenetically, should be of great interest. 



Finally an expression of gratitude must be made to Mr E. E. Green, 

 who provided the material for experiment and thanks are also due to 

 Professor Punnett and Mr L. Doncaster for much advice. 



