the colours of certain Lepidoptera. 



323 



Conclusions are best deferred until the description of 

 experiments upon moths produced by the larvae of Ex- 

 periment III., 1887. 



As in the last experiments, it is impossible to decide 

 the number of moths which laid the eggs. The larvse of 

 these experiments were hatched on June 16th, 1888, and 

 other days not far removed. The young larvae were kept 

 together until July 3rd, when many were arranged in 

 Experiments I., II., and III. On July 7tli a further 

 number were divided between II. and IV. 



Experiment I. 



Dark Surroundings 



(dark twigs). 



23 larvae intro- 

 duced. 



More dark twigs 

 added, although 

 many were j^resent 

 already. Marked ef- 

 fects had been pro- 

 duced. 



22 larvfe living : 

 compared with 



others these were 

 considerably darker 

 than any of the 

 others, including 

 II. Only 1 or 2 

 larviE were greenish 

 brown, like many of 

 II., and these less 

 distinctly so. 



■i had spun. 



Only five larv.v, 

 could be relied on 

 (the others having 

 spun or changed 

 colour before pu2)a- 

 tion). They were 

 dark, but not ex- 

 tremely dark forms, 

 but considerably 

 darker than the 7 

 of Experiment I. de- 

 scended from moths 

 of II., 1887. 



EXPEEIMENT II. 



Dark Surroundings 

 (dark twigs covered 

 with black paper). 



12 larvae intro- 

 duced; 8 more ad- 

 ded July 7. 



At this date twigs 

 covered with black 

 paper were substi- 

 tuted for the ordi- 

 nary dark ones. 

 Their number was 

 gradually increased 

 for about a week. 



20 larYa3 living; 

 many of these larvae 



were greenish 

 brown. The slight 

 effect of the black 

 twigs here was one 

 of the most inte- 

 resting things in 

 this comparison. 



3 had spun. 



Only 8 remained, 

 the rest having 

 spun. The 8 are 

 full-fed and dark- 

 ish, although by no 

 means extremely 

 dark. 



4 larvte could be 

 relied on. They are 

 of a rather dark 

 greenish brown, cer- 

 tainly darker than 

 IV., but not greatly 



Experiment III. 



Green 

 Surroundings. 



36 larvae intro- 

 duced. 



Examined; much 

 effect was seen to 

 have been produced. 

 13 larvffi removed 

 from here and in- 

 troduced into IV. 



21 larvffi living. 

 These larvae were 

 much greener than 

 I. and II. ; only two 

 of them were dark 

 and brownish ra- 

 ther than green, 

 and these not very 

 dark. 1 larva had 

 spun at this date, 

 and 1 previously. 



Many had now 

 spun, for the most 

 part a few days pre- 

 viously. 



Only 2 remained ; 

 both greenish larvae 



1 larva only could 

 be compared : it re- 

 sembled those of II. 



Experiment IV. 



Green 

 Surroundings. 



July 7. — 8 larvae 

 introduced. 



13 larvae intro- 

 duced from III. 



21 larvffi living. 

 These were like III. , 

 except that none 

 were very brown. 

 The marked green- 

 ness of III. and IV. 

 is remarkable as 

 compared with the 

 less marked dark- 

 ness of the other 2 

 lots, even I. 



Many had now 

 spun. 



5 larvfe could be 

 compared ; 4 were 

 of a light greenish 

 brown, and much 

 the lightest colour- 

 ed larvae at this 

 date in this set of 

 experiments, 1 re- 

 sembled II. and III. 



