62 



healthy tissue, a pattern of concentric dark, yellow, and green ; and 

 in its last larval stage, when its greater weight necessitates a hang- 

 ing position, the pattern becomes more complicated, simulating 

 leaves in light and shade, in profile, or fore shortened, their edges 

 picked out in white colour for the high lights with darker shadow in 

 immediate proximity for contrast, with other details of colour to 

 match the depths of shade in the interior of the food plant, and other 

 areas suggestive of foliage in full sunshine. 



The larvae of the Poplar Hawk moth, the Eyed Hawk moth and 

 Privet Hawk moth were also shown. The two former of these vary 

 in tone to match the special foliage on which they feed — light blue- 

 green specimens tone with leafage in shade or seen by reflected 

 light ; yellower ones simulate leafage seen by transmitted sunlight ; 

 the minutely yellow, or white, stippled skin of the larvae simulates 

 the cell structure of the leaf, and diagonal lighter and darker tones 

 mimic the leaf surface broken by veins with light and shade 

 accurately related. In the Eyed Hawk and Privet Hawk larvae, to 

 these breakings up of the surface, is superadded change of ground 

 colour, the under-side in the characteristic attitude assumed by the 

 caterpillar being lightened to kill the shadow cast by the solid body, 

 giving at a short distance the effect of plane leaf surface rather than 

 of solidity. In the larvae of the " Swallow Prominent," this device 

 is further supplemented by a shiny skin, which takes reflections of 

 green from its surroundings. 



Brief reference was then made to caterpillars needing no 

 concealment, unpalatable by their urticating hairs, as the " tigers," 

 the fox " moth, and " vapourer" ; and to the uneatable sociable 

 caterpillars, such as those of the " buff-tip'' moth, which pool their 

 inedibility to the common advantage, and further advertise it by a 

 colouration strongly suggesting a nest of wasps. Best protected of 

 all seem to be the evil-smelling larvae of the "goat" moth, with 

 their warning red colour. Considerable discussion followed the 

 address, and the conclusion of the lecturer was fully endorsed that no 

 serious study of the colour problem in Nature can be made except in 

 the open field, that it is imperative to follow the life history of 

 insects in their unspoiled natural surroundings. At the same 

 meeting Mr. W. Parkinson Curtis exhibited a Syntomid moth, 

 Psilopleura haemasoma D. Jones, of which there is not as yet a 

 published description. He gave a description of the insect, and 

 showed drawings and microscope slides illustrating its characters. 

 He also explained the characters of the family Syntomidae, and 

 the genus Psilopleura, and by means of diagrams on the black- 

 board illustrated the evolution of the particular type of wing- 

 neuration found in the insect exhibited. 



Mr. Curtis's paper will be found in full with coloured plate on 

 page 95. 



Sectional meeting, April 27th. A paper was read by H. J. 

 Waddington, Esq., f.l.s. It was kindly prepared by Miss Pierce, of 

 Bournemouth, and entitled, 1 1 Notes on Forest and other biting 

 Flies." The subject was illustrated by a special series of lantern 

 slides. 



