108 The Colour of Papon and their Surroundings. [Feb. 10, 



the genus Ephyra. I observed this genus in 1883 (i.e., E. pendularia, 

 E. omicronaria, and E. orbicularia), and the results are published in 

 1 Entom. Soc. Trans.,' 1884, pp. 50 — 56. The most curious result of 

 the observation was the establishment of the fact that the green and 

 brown larvae always produce pupae of the same colour. I think it is 

 very probable (from the consideration of other partially published 

 observations), although entirely untested in this genus, that the 

 colours of the larvae, and through them of the pupae, could be con- 

 trolled by tbe selection of appropriate surroundings during the whole 

 or a large part of the larval stage. Concerning the different species 

 made use of, E. orbicularia is variable, E. pendularia regularly 

 dimorphic green and brown, and E. omicronaria dimorphic, with the 

 brown forms very rare. The relative numbers of the green and 

 brown larvae and pupae of E. pendularia vary at different times of the 

 year, the green forms greatly predominating in the summer brood, 

 while they are not so abundant in the winter brood. When the 

 parents of any set of larvae were both of the same colour in the 

 larval stage there was a much larger proportion of that same colour 

 in the resulting offspring. I made some observations upon the situa- 

 tions selected for pupation, thinking that these might show some 

 relation to the pupal colours, but the results were not convincing, 

 and were certainly highly irregular, but the experiment was not 

 carried out in the best way, for there was not a sufficient quantity of 

 both colours in the surroundings. Dr. Wilhelm Miiller, of Greifswald 

 (Spengel, ' Zool. Jahrb.,' vol. 1, 1886, p. 234), calls attention to this 

 remarkable and constant relation of larval to pupal colours, and 

 expresses the belief that it is entirely exceptional, a statement which 

 is of importance, when it is remembered that Dr. Miiller has worked 

 carefully for many years on the South American larvae. Hence 

 certain species of Ephyridae afford an interesting contrast with all the 

 other species of exposed pupae which have been hitherto observed. 



VII. Experiments upon the Colours of the Cocoon in Saturnia 

 carpini. — At the suggestion of Mr. W. H. Harwood I made some 

 experiments upon this species, and found that four cocoons which 

 were spun in the corners of black calico bags were very dark brown 

 in colour, while those of other larvae which had been freely exposed 

 to light until after they had begun to spin, and which were not sur- 

 rounded by dark surfaces, were nearly all perfectly white, and when 

 darker of a much paler tint, and very different from the four men- 

 tioned above. Thus Mr. Har wood's suggestion seems to be entirely 

 confirmed, and another instance of the influence of surroundings is 

 added, and one which it appears cannot be explained in any way 

 except by the supposition of the existence of a complicated physio- 

 logical, and apparently a nervous circuit. 



