COLOURING OF CHRYSOPHANUS PHLCEAS. 



335 



Godalming figures, mentioned that for local reasons his figures 

 would be somewhat lower than the average. Allowing for these 

 explanations, we may safely take the average temperature of Mr. 

 Frohawk's captures at about 64° for their whole pupal period, 

 and 60° for the more critical period of twelve days. 





Own. 



(2.) 



Brighton 



municipal 



(Dr. Newshohne). 



(3.) 



Kew 

 Observatory. 



(4.) 



West 

 Kensington. 



(5.) 



Godalming, 

 N.W. Surrey. 



The 8 days 

 The 13 days 



(not 

 kept) 

 59.8 



68.10 

 6Q.3 



70.21 

 59 85 



72.23 

 60.60 



67.4 



58.7 



The 90 days 





64.65 



64.00 



65.25 



62.19 



Here I might perhaps have let the matter rest had my object 

 been merely a controversial one, instead of being, as it is, that 

 of throwing as much light as possible upon the question. I go 

 on therefore to invite attention to the fact that the mean daily 

 temperature may be several degrees less than the average of the 

 actual temperature to which an object is exposed when there is 

 much sunshine. It is, I believe, quite impossible to say, with 

 any approach to accuracy, how much should be added for sun- 

 shine, as this would depend on the amount of sunshine, aspect, soil, 

 wind, humidity, surroundings of the object, and perhaps other 

 considerations. But from enquiry made of competent authority 

 I believe meteorologists would not put it, for either of the 

 periods in question, and certainly not for the latter period of 

 twelve days, and for objects circumstanced as the pupae of C. 

 phloeas are, at so much as five degrees. Few pupae are exposed 

 to full sunshine, and I believe that the pupa of C phlaas is to be 

 found attached to the stems and under sides of the leaves, near 

 the ground, of sorrel and other field-plants. In captivity, though 

 a few of mine pupated close to the muslin cover of the glass 

 cylinder in which the larvae were kept, the great majority crept to 

 the bottom. As to sunshine I have made enquiry, and find the 

 important period was not a remarkably sunny one. At Brighton, 

 which being on the south coast is particularly sunny, the daily 

 average was, for the 20 days, 8.01 hours; for the last 12 days, 

 7.10 hours. At Kew it was, for the 20 days, 6.94 hours ; for the 

 last 12 days, 5.5 hours. Allowing even as much as 5 degrees 

 for sunshine, we should have : — 



For the whole 20 days, a temperature of 69° 

 For the last 12 days „ ,, 65° 



neither figure approaching my '* high temperature " of 80° and 

 upwards, 



2 h2 



