ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 35 



outlines of his regions, of Darwin in laying down the principles of geo- 

 graphical distribution in the Origin, and of Wallace in his masterly 

 development of the subject in his great works on the geographical 

 distribution of animals. These principles have been tested by an appeal 

 to the facts collected with consummate skill and care, from the most critical 

 area in the world, and assuredly they have not been found wanting." 



Seasonal Dimorphism in Butterflies.* — F. A. Dixey gives an account 

 of observations by himself and by G. A. K. Marshall. Thus Catopsilia 

 pomona Fabr. (including G. catilla Cram.) and C. crocale Cram, are 

 phases of one species, which in one part of their range appear to be in 

 relation with the seasons. Similarly G. pyranthe L., is conspecific 

 with G. gnoma Fabr., in more marked, but apparently not universal 

 correlation with the seasons. Some cases of simultaneous occurrence of 

 dimorphic forms are explained as due to an overlapping at the change of 

 seasons, or lack of differentiation in the climatic conditions. 



Marshall has proved by actual breeding the specific identity of six 

 pairs of forms. The final stage can, in many cases, be influenced by the 

 artificial application of heat or moisture during the pupal condition. 



Colour of Silk.f — D. Levrat and-A. Conte have made experiments on 

 Bombyx mori and Attacus orizaba, and find that an ingested substance, 

 e.g. pigment, can pass from the gut to the silk-glands by the blood. 

 Greenish silk is due to chlorophyll, the spectrum of which was demon- 

 strated in the blood of Anther rea yama mai. As Dubois and Blanc have 

 shown, the yellow colour of some silk is directly due to the diet of mul- 

 berry leaves. 



Study of an Ant.J — Adele M. Field has studied Stenamma fulvum 

 piceum for three years. From among her interesting observations, we 

 select the following. There is no regeneration of the antennae. A 

 single worker may live apparently well in isolation for six months. 

 Familiarity with the nest-aura does not reconcile aliens. The kings 

 have the distinctive odour of their blood-relations. Virgin queens 

 show marked preference or dislike toward certain kings ; queens having 

 once mated permit no close approach of an alien king, and do not 

 respond to the attentions of kings of their own lineage ; they may drop 

 their wings without assistance from workers ; light and warmth appear 

 to be required for the stimulation of the king and queen to mating. 

 Some experiments suggest definite intellectual memory. 



The ants in question are very discriminating in regard to the odour 

 of all ants introduced into their dwelling, whether of their own or 

 some other lineage. The hereditary odour descends through the mother, 

 and is unaffected by the father whether of the same lineage or of an 

 alien colony. A cause for the hostility of one colony to another of the 

 same species and variety is a difference of odour, coincident with dif- 

 ference of age in the individuals composing the colony. Many experi- 

 ments in regard to sensitiveness to light were made. 



* Trans. Entomol. Soc. London, 1902, pp. 189-218 (1 pi.). 



t Comptes Rendus, cxxxv. (1902) pp. 700-2. 



% Proc. Acad. Nat. Sci. Philadelphia, 1902, pp. 599-625 (2 figs.). 



D 2 



