588 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Notes on Larvae of Arpyia Vinula.* — E. Balducci describes the- 

 larval stages of Arpyia (Dientnitra) vinula and the colour changes. 

 He has given particular attention to the defensive organs, the two- 

 caudal appendages, and the peculiar anterior organ on the first segment 

 below the mouth, from which irritant fluid is squirted out. 



Influence of Nutrition and Humidity on Lepidoptera.f — Arnold 

 Pictet has made many experiments on the influence of nutrition and 

 humidity in promoting variations. Food that is difficult to digest or 

 absorb inhibits larval development, prolongs the larval period, and 

 shortens pupation. Imperfect pigmentation, in extreme cases albinism, 

 is the result. Insufficient food has the same effect. Rich, abundant, 

 digestible food intensifies pigmentation and promotes melanism. The 

 size is also modified by nutrition. The males vary more than the females. 

 The variations induced by nutrition increase in intensity with each 

 generation, and seem to become transmissible. But after several genera- 

 tions there is a return to the primitive type. Nutrition affects the 

 colours of the larvae as well as of the imagines, and the larval variations 

 may be cumulative during two or three generations. Nutrition also 

 affects the secondary sexual characters. Bad nutrition leads to an in- 

 crease in the number of males, but rich nutrition does not increase the 

 number of females. 



Humidity in the form of rain or saturated air seems to be a factor 

 in inducing partial melanism. Two exceptional experiments showed a 

 tendency to albinism. The melanistic characters appear along the 

 course of the nervures. There was no evidence of inheritance, but the 

 author emphasises " la loi de Vaccoutumance" that is to say, the fact that 

 individuals become insensitive to factors which influenced their parents. 



Pupal Suspension of Thais.J — T. A. Chapman describes the in- 

 tricate process by which the larva and pupa of Thais make the girth 

 leave its usual situation and become attached to the nose-hooks. 



Numerical Proportion of Mimic to Model.§ — Horace A. Byatt 

 notes that in a collection of Limnas chrysippus and its mimic Pseuda- 

 crcea poggei, there were 17 of the latter to 367 of the model. This 

 occurrence in considerable numbers of what has hitherto been regarded 

 as the rarest species of Pseudacraia, supports the hypothesis that the 

 mimics of this group are Mullerian rather than Batesian. Professor E. B. 

 Poulton adds a note comparing the details of the mimetic resemblance 

 borne by Pseudacraia poggei to Limnas chrysippus with those of the 

 other great Nymphaline mimic Hypolimnas misippus 9 . 



Experiments on Bombyx mori.|| — Vernon L. Kellogg finds (1) that 

 there is no regeneration of mutilated or destroyed developing gonads in 

 Bombyx mori, even though the organs are destroyed or mutilated as 

 early as just after the second larval moulting ; and (2) that the 

 destruction of the primary reproductive organs (ovaries and testes) 



* Bull. Soc Entom. Ital., xxxvi. (1904) pp. 117-22 (1 pi.). 



t Mem. Soc. Phys. Geneve, xxxv. (1905) pp. 1-127 (5 pis.). 



X Trans. Entomol. Soc. London (1905) pp. 203-18 (1 pi.). 



§ Tom. cit., pp. 263-8 (1 pi.). || Journ Exp. Zool., i. (1904) pp. 601-5. 



