( XXXV ) 



Gastropacha quercifolia was highly sensitive to such a stimulus 

 up to the beginning of hybernation, but that during and 

 after hybernation, all such susceptibility entirely ceased. The 

 larvaj were also sensitive, during the same period, to brown 

 and black bark, which caused the appearance of corresponding 

 tints. In all experiments the food made use of was the same, 

 viz. the leaves of the hawthorn. 



Odontopera bidentata was also sensitive to the same sui*- 

 roundings, lichen in the environment producing the well- 

 known green patches on the dorsal surface. 



The rigid restriction of the sensitive period to the earlier 

 part of larval life in the case of quei'cifolia suggested a set 

 of transference experiments on the highly sensitive larva of 

 Amphidasis betidaria, carried out in the summer of 1896. The 

 result was to prove that this species remains sensitive, at least 

 to the strongest stimuli, viz. those provided by dark bark, for 

 nearly the whole of larval life. 



Papers. 



Mr. 0. E. Janson communicated a paper " On the genus 

 Theodosia, and other Eastern Goliathides, with descriptions of 

 some new species." 



Colonel C. SwiNHOE communicated a paper on *' New 

 genera and species of the family Lymantriidse in the National 

 Collection." 



Mr. G. W. KiRKALDY communicated a " Memoir on the 

 Khynchota collected by Dr. Arthur Willey chiefly in Berara 

 and Lifu." 



Professor E. B. Poultox read an account of "Experiments 

 in 1893, 1894, and 1896 on the colour-relation between certain 

 lepidopterous larvse and their surroundings, and especially the 

 effect of lichen-covered bark upon Odontojjera bidentata and 

 Gastropacha quercifolia." 



Wednesday, October 7th, 1903. 



Professor E. B. Poulton, M.A., D.Sc, F.E.S., President, 

 iQ the Chair. 



