42 SUMMARY OF CURRENT RESEARCHES RELATING TO 



summer 50 p.c. and in autumn (>o-7.~> p.c. of the Pieris larvae examined 

 were infested with this parasite, which has therefore considerable economic 

 importance. 



Alleged Fixation of Carbon by Chrysalids.* — R. Dubois and 



E. Couvreur refer to Marie von Linden's conclusion that some chrysalids 

 can utilise carbon dioxide, fixing the carbon. The authors have 

 repeated the experiment with Pieris brassica, but without any success. 



Marie von Linden f responds that there is no doubt that the 

 chrysalids of Pa/pilio podalvrius and of HylopMla prasinana become 

 heavier in an atmosphere rich in carbon dioxide, while they become 

 lighter in atmospheric air. What is true of these need not be true of 

 Pieris brassim, but it may be that Dubois and Couvreur worked with 

 too dry an atmosphere. The assimilation of C0 2 requires humidity. 



Chromosomes in Spermatogenesis of Anasa Tristes.^ — Katharine 

 Foot and E. C. Strobell find that there are 22 spermatogonia! chromo- 

 somes ; that none of these retain their morphological individuality 

 throughout the growth period ; that in the early prophase the so-called 

 odd (heterotropic) chromosome of Wilson and Montgomery (i.e. the 

 eccentric chromosome of the later prophases, or metaphase) resembles in 

 no way a nucleolus, and is morphologically wholly unlike the same 

 chromosome figured by Wilson at this stage ; that the 11 chromosomes 

 of the first spindle are all bivalents, and that the 11 chromosomes of 

 the second spindle are all univalents ; that in both the first and second 

 spindles one chromosome — which is believed to be the eccentric chromo- 

 some of the late first prophase — often lags in division, but that normally 

 its final division occurs in both spindles 



How Ants Find their Nest.§ — H. Pieron points out that there is 

 considerable variety in different species. In Formica fusca, F. cinerea, 



F. rvfibarbis, Camponotus pubescens, etc., the orientation is predomi- 

 nantly visual ; in Aplmnog aster barbara, A. testaceo-pilosa, etc., which 

 are very blind, the orientation is mainly muscular ; in Lasius flaws 

 and L. fuliginosus it is mainly olfactory. The first method admits of 

 orientation from the greatest distance, the muscular method is only for 

 short distances. There is most frequently a combination of methods. 

 The olfactory method is relatively rare and never exclusively followed. 



Psychobiology of Humble Bees.|| — Wladimir Wagner gives an 

 account of the pyschobiology of humble bees, in which he deals with 

 the social instincts predominating at different periods of the life-history. 

 He concludes that the common life of the so-called " social insects " 

 represents neither a family, nor a herd, nor a society, and still less a 

 state unity. The study of various forms of biological organisation in 

 the animal kingdom shows absolutely no connection between the life of 

 social insects and true sociality. It represents a special form of sym- 



* C.R. Soc.^Biol. Paris, lxii. (1907) pp. 219-20. 



t Tom. cit., pp. 428-9. 



% Aruer. Journ. Anat., vii. (1907) pp. 279-316 (3 pis. and 4 figs.). 



§ C.R. Soc. Biol. Paris, lxii. (1907) pp. 216-17. 



| Zoologica, xix. (1907) heft 46, p. 1-239 (86 figs.). 



