62 SUMMARY OF CURRENT RESEARCHES RELATING TO 



instincts have selected the habitat. The behaviour of insects i3 deter- 

 mined by their elementary reactions to the chemical and physical condi- 

 tions of the environment. 



Protective Coloration.* — A. H. Thayer contributes a memoir on 

 protective coloration in ite relation to mimicry, warning colours and 

 sexual selection. He begins his paper by a statement of the artist's 

 claims to be the only judge of all matters of colour, pattern, visibility, 

 and their effect on the mind. He says that the pattern and coloration 

 of butterflies are all evolved for the sake of rendering them invisible, as 

 a pattern is less conspicuous than a monochrome ; he also holds that the 

 mimicking is not of each other, but of some flower or of some organic- 

 form, for if they were mimicking each other there would be no necessity 

 for the great detail, but if they were mimicking flowers then they would 

 derive the greatest benefit from the minutest details. He holds that the 

 syncryptic resemblance to flowers gives a full explanation of all the 

 patterns and colours. His paper contains many very important sugges- 

 tions, e.g., the concealing effect of iridescence, the overflow of individuals 

 from a concealing region to one less favourable, and the resemblance of 

 butterfly patterns in general to flower-masses and the shadow-depths 

 between them. 



E. B. Poulton f criticises Thayer's paper on Protective Coloration. 

 He holds that the syncryptic resemblance is a highly improbable interpre- 

 tation and that, in spite of Thayer's repeated statement to the contrary, 

 zoologists have not entirely misunderstood the principles underlying the 

 cryptic pattern. He also holds that the effacive shading of the body and 

 the brilliant pattern of the wing help in preserving the life of the butterfly, 

 as they misdirect the attack of the enemy. He believes that Thayer's 

 suggested interpretation of mimetic resemblance is untenable, but he 

 admits having had ideas similar to Thayer's in regard to warning colours. 

 He concludes his paper by saying that naturalists owe Thayer a large 

 debt for many new points of view and illuminating suggestions. 



5. Arachnida. 



Stridulation in Scorpions. | — R. I. Pocock describes a new stridula- 

 ting organ in scorpions discovered by W. J. Burchell. This organ 

 consists of the modified pectines and granular areas on the overlying 

 sternal plate. These modifications were a puzzle until a reference and 

 explanation was found in Burchell's MSS. The author has now given a 

 full description and careful drawings of this organ, and he adds that 

 it is purely of aposematic significance. 



New Chelifer.§— R. T. Lewis describes a new species of Chelifer. 

 His attention was first drawn to it in 1890 by a specimen sent from 

 Natal. This, when compared with a number of specimens in the British 

 Museum, was found to be new. The Chelifer is bright red in colour, with 

 an ovate body much narrowed in front and semicircular behind. On 

 account of the beautifully sculptured segments it is proposed to name the 

 species Chelifer sculpturatus. 



* Trans. Ent. Soc. Lond., 1903, pp. 553-09. f Tom. cit., pp. 570-5. 



% Ann. Nat. Hist., xiii. (1904) pp. 56-62 (1 pi."). 



§ Jonrn. Quckett. Micr. Club, viii. (1903) pp. 497-8 (1 pi.). 



