57G SUMMARY OF CURRENT RESEARCHES RELATING TO 



Kellogg tried about a hundred experiments. Dry air, friction, heat, 

 sulphuric acid, phosphoric pentoxide and glacial phosphoric acid were used 

 as dehydrating agents, and these increased the proportion of partheno- 

 genctically developing ova. 



At the same time' he tried other treatment, not dehydrating, and 

 got hardly less favourable results. He thought that hydrogen ions 

 might be the development-inciting factor, but other experiments did 

 not bear this out. All that he can say at present is that a great variety 

 of stimuli increase the usual proportion of parthenogenetic ova. 



Mouth-parts of Solitary Bees.* — R. Demoll has made a compara- 

 tive study of the mouth-parts in solitary Apidse, and shows the gradual 

 series of transformations from relatively simple conditions, as in Hal id us 

 and Heriades, to great specialisation. He discusses the adaptations of 

 the mouth-parts to flowers, and the theoretical interpretation of the pro- 

 cess by which these adaptations were wrought out. He is disinclined to 

 allow that the parts were in any degree moulded by use. The memoir 

 includes an interesting discussion of the rudimentary parts in parasitic 

 bees, but here again the Lamarckian interpretation is considered and 

 rejected. 



Copulatory Organs of Solitary Bees.f — J. Strohl has studied the 

 male copulatory organs in numerous genera. In the females there are, 

 in solitary bees, no corresponding parts. Each genus has its distinctive 

 peculiarities, except, perhaps, in some of the parasitic bees, and genera 

 which resemble one another as regards copulatory organs, e.g. Andrena 

 and Biareolina, have other evidences of relationship. The conditions 

 as regards species are varied ; the species of Andrena, or of Halktus, or 

 of Nomada, are not very different (as regards copulatory organs), but 

 those of Osmia are. The same is true, with the same examples, of 

 individual variability. Closely related species are not usually very 

 different in copulatory organs, and the constant varieties of Nomada 

 ruficornis do not show marked differences as regards copulatory parts. 

 Similarly Hal ictus albipes resembles H. calceatus, of which it is, perhaps, 

 a variety. Parasitic bees seem to be relatives of their hosts ; the copu- 

 latory organs of Nomada are like those of Andrena, those of Sphecodes 

 like those of Halictus. The facts are against attaching importance to 

 physiological isolation, as far as variations in the reproductive parts are 

 concerned. The author believes in the origin of varieties by a continua- 

 tion of the variations which germinal selection secures. 



to v 



Development of Ovary of Polistes pallipes.J — W. S. Marshall has 

 studied this wasp in reference to the history of the cellular elements of 

 the ovary. It begins as a syncytium with similar nuclei ; cell-boundaries 

 appear ; ovarian tubules develop ; these differentiate into three parts ; 

 oocytes and primitive nurse-cells become distinguishable ; mitosis occurs 

 in the epithelial and primitive nurse-cells ; the latter are finally absorbed 



* Zeitschr. wiss. Zool., xci. (1908) pp. 1-51 (2 pis. and 11 figs.). 

 t Zool. Jabrb.. xxvi. (1908) pp. 333-84 (3 pis. and 2 figs.). 

 \ Zeitschr. wiss. Zool., lxviii. (1907) pp. 173-213 (3 pis.). 



