308 Mr. F oiilton' s fm'ther experiments upon 



brown varieties of the larvae of E. omicronaria, producing 

 brown pupae, are not unknown, for I bred one in 1883 

 (Trans. Ent. Soc. Lond. 1884, p. 51, and Plate I., fig. 10). 

 It would be desirable to repeat these experiments upon 

 other species of the genus. 



10. Experiments in 1887 upon Melanippe montanata. 



A female captured at Oxford laid the eggs from which 

 the larvae of these experiments were hatched. 



Experiment I. 



Dark surroundings : dead leaves 



and bits of brown stick intermixed 



with food-plants (primrose 



and polyanthus). 



June 30. — 27 newly hatched larvii^ 

 introduced. 



July 17. — 27 larva' ; very remark- 

 able difference between these and II., 

 the latter being much lighter. 



July 30. • — 27 larvae ; still much 

 darker than II. 



Aug. 21. — 27 larviE ; the difference 

 was now much less, although these 

 were still probably the darker lot. 



Aug. 30. — 27 larviB ; still appa- 

 rently slightly darker. 



Experiment II. 



Green surroundings : green leaves 



of food-plant alone, but these 



became brown from time 



to time towards end of experiment. 



June 30. — 23 larva; from same 

 batch of eggs introduced. 



July 17. — 23 larvaj ; about 9 mm. 

 long in both I. and II. 



July 30. — 20 larvpe ; both lots 

 were brown, but these far paler. 



Aug. 21. — 19 larviB ; the larvre 

 had been somewhat neglected, and 

 the leaves had partially become 

 brown, hence the darkening of these 

 larva}, and smaller difference be- 

 tween the two sets. 



Aug. 30. — 20 larvae. 



It is quite evident that these larvae are very sensitive, 

 and can adjust their shade of brown to that of their 

 surroundings, becoming very light in a green environ- 

 ment. Two adjustments took place in the larvae of 

 Experiment II., for they became at first pale upon the 

 green leaves, and then dark when the leaves were allowed 

 to become brown. The first change is shown to have 

 been complete in a little over a fortnight ; it probably 

 occupied a still shorter time. 



11. Experiments in 3 888 upon Boarmia roboraria. 



A few larvae were obtained from eggs laid by a female 

 moth captured by Mr. Arthur Sidgwick, who kindly 

 allowed me to experiment with them. 



