the colours of certain Lepidoptcra. 301 



Experiment I. : Dark Surroundings. 



May 15. — 11 larvaj were placed on the food-plant intermixed with dark 

 twigs. 



May 16. — 2 larvre were removed and placed in green surroundings. 



May 20. — More dark sticks were added. 



May 27. — Larva9 placed in a larger cylinder with still more dark twigs : 

 all the 9 were alive and healthy. 



June 11. — The first larva spun up. 



Experiment II. : Green Surroundings. 



May 13. — 1 larva hatched. 



May 14. — 5 larvte hatched. 



May 20. — Placed in green surroundings, viz., only the leaves and green 

 shoots visible. 



May 27. — Combined with Experiment III. At this date some of the 

 6 larvie were light coloured, while others were as d;irk as those of Experi- 

 ment I. 



Experiment III. : Green Surroundings. 



May IC. — 2 larvie hatched, and 2 were transferred from I. 



May 20. — Placed in green surroundings. 



May 27. — The larvte of Experiment II. added to these, making 10 

 altogether. 



June 10. — All larva^ were now nearly mature, and were carefully com- 

 pared together. There was a decided difference between the shade of 

 larvae exposed to dark surroundings (I.) and those exposed to green 

 (II. and III.). The difference was not nearly so marked as in many 

 other siDecies, e.g., Crocallis elhiguavia, but was nevertheless distinct, 

 and in the same direction, dark surroundings producing darker larvtc, 

 green surroundings li-hter ones. 



June 11. — 1 became mature and spun up. 



As in so many other cases in which these experiments 

 have been made, the dark larvae are far more perfectly 

 concealed than the light ones, but the latter are much 

 less conspicuous on the leaves than the dark ones would 

 have been. The very rapid development of these large 

 larvae is somewhat remarkable. 



4. Experiments in 1889 upon Catocala electa. 



Eggs of this species were kindly sent me by my friend 

 Mr. William White. 



May 28 : 2 larvae, at this date about 21*7 mm. long, 

 hatched May 12 and 13, together with 4 larvas, about 

 14'5 mm. long, hatched May 16 (2 on this date), 18, and 

 20, were divided into two lots as equally as possible as 

 regards size and colour, and were subjected to dark and 

 green surroundings respectively. 



