( clviii ) 



pletely valueless owing to the discovery by Sikora that these 

 insects reacted phototropically to the light or dark hue of 

 their surroundings. It appeared that the factors necessary 

 to the production of dark pigmentation were exposure in 

 some earlier instar to light while in a dark environment. 

 Individuals kept in complete darkness did not react. In his 

 experiments a strain of lice which showed only pale greyish 

 forms during the first three or four generations then com- 

 menced to produce dark (so-called melanic) individuals, 

 presumably owing to the white sides and grey flannel in the 

 box having been blackened with excrement by the insects 

 during this period. With regard to the lengthy series of 

 breeding experiments he had carried out the results curiously 

 simulated some features of discontinuous variation, suggesting 

 Mendelian inheritance in which the proportion of dark and 

 light forms did not conform to theory. It appeared, in view 

 of Sikora's discovery, that this was to be accounted for by 

 the chance exposure to light of susceptible larvae or nymphs 

 while amid dark surroundings during examination; the small 

 glass-bottomed boxes in which the broods were reared being 

 normally carried wrapped up in paper in a vest pocket, 

 where little, if any, light could penetrate. The nature of the 

 darkening was apparently twofold: (1) dependent upon the 

 pigmentation of the chitinised plates, and (2) to the suffusion 

 of the general skin surface. His own results suggested that, 

 while the first character mighl be present without the second, 

 the second was always accompanied by the first. 



Paper. 



The following paper was read, the author illustrating his 

 subject with photographs shown in the epidiascope. 



" Notes on Australian Sawllies, especially ' Authors' Types ' 

 and the Specimens in the British .Museum of Natural History 

 and the Hope Collection in the Oxford University Museum, 

 with Diagnostic Synopses of the Genera and Species," by the 

 Rev. I\ D. Morice, M.A., F.E.S. 



