196 THE ENTOMOLOGIST. 



which, however, as might be expected, the amploid wing breadth 

 is extreme) ; sometimes a falcoid margin goes with an amploid 

 costal marking, or else both details are without character. 



The above note on the natural conditions under which the 

 sun-loving Vanessid larviB live necessarily suggests their ex- 

 posure to great contrasts of temperature, which would yet in 

 England be less severe, owing to less sunshine (also less in 

 intensity) than on the Contuient, especially in the southern 

 parts. Already in a note in the Ent. Rec. pt. 2, 1910, I recorded 

 certain measurements of temperature taken among the nettles 

 of a hedge-bank, suggesting that the " r/ round climate'' in 

 which the Vanessid larvfe lived was very different from the con- 

 ditions we ourselves moved in. Thus on the nettles the sun- 

 shine causes temperatures up to and over 37-40^ C. for many 

 hours, even in England, and the sun -loving larvfe will not 

 shelter from it till the heat rises to 45° C. (compare also the 

 sunshine records of meteorological stations). When night falls, 

 the cold among the nettles is greater than higher in the air by 

 condensation and evaporation of moisture (compare the meteoro- 

 logical records of the ground or grass temperature at night). 

 Often slight ground frosts occur up to June, and again already 

 in August, while on the same dates by day the sun could shine 

 and cause records of over 40° C. Only a series of dull cloudy 

 days would produce a more medium range of temperature, but 

 every glimpse of sunshine would be utilized by the larvae to 

 bask in. 



As has already been suggested, the normal or commonest 

 form of V. urtica appears like a " cross " between the forms 

 characteristic of the day temperatures (amploides) and of the 

 night and shade temperatures (falcoides), as, indeed, should be 

 expected. But while the southern variety of V. urticcs var. 

 iclmusa, by its very broad, straight-bordered wings, shows that 

 warmth and sunshine are predominant in the climate in which 

 it lives, the English V. urt.icce are much more falcoid in character, 

 being, indeed, often of the form falcoides , and proving that here 

 the temperatures belotv 15-20° C. exert " the main pull " in their 

 development. 



Of V. io, the forms corresponding to the vars. falcoides and 

 amploides of V. urticce are vars. mesoides and teloides respectively 

 {vide antea, pts. 12, 1909 and 1910, and Ent. Rec. pt. 1, 1911) ; 

 and, again, the var. mesoides (the shade-temperature form) 

 seems to be most common in England. This form, in addi- 

 tion to the characteristic alterations in the ocelli, also often 

 shows the "falcoid" characters in wing shape and costal 

 blotch (which, however, never appear in var. teloides, the heat 

 form). 



After rearing some twenty thousand specimens in all of both 

 species, I have been forced to the conclusion that no other 



