ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579 



also a brown phase, and similar aberrations occur in certain Homoptera. 

 The author suggests that the pink individuals are mutants, but breeding 

 experiments are necessary. On the sport or mutation hypothesis we 

 should expect pink individuals mated inter se to produce only pink 

 individuals, and the same should result mutatis mutandis in the case of 

 the brown forms. Pink or brown individuals crossed with the common 

 green form may be expected to give offspring in the Mendelian propor- 

 tion, with the pink and brown characters acting as recessives. 



Chromosomes of Anasa tristis and Anax Junius.* — George 

 Lefevre and Caroline McGill confirm E. B. Wilson's results as regards 

 the chromosomes in the spermatogenesis of Anasa tristis. They find the 

 number to be 21, and they observed the presence of an accessory or 

 heterotropic chromosome, which behaved as Wilson described. Their 

 results are quite at variance with those of Foot and Strobell. 



The behaviour of the chromosomes in the spermatogenesis of the 

 dragon-fly, Anax junivs, closely parallels the conditions in Anasa. 

 In the differentiation of its chromosomes as w-chromosomes, macro- 

 chromosomes, and chromosomes of intermediate sizes ; in the occurrence 

 of an odd number of chromosomes (27) in the male groups, and of this 

 number plus one (28) in the female groups ; in the presence of an 

 accessory or heterotropic chromosome which persists as a condensed body 

 throughout the growth-period and passes undivided at the second 

 maturation-division into one of the spermatids, a strict parallelism may 

 be recognised between Anax and those insects — of which Anasa tristis 

 may be taken as a type — which possess a heterotropic chromosome. In 

 at least one of the Odonata, therefore, a dimorphism of the spermatozoa 

 occurs, and the theory of the determination of sex by differentiated sex- 

 chromosomes receives additional support. 



Wax-glands of Flata (Phromnia) marginella.f — E. Bugnion and 

 N. Popoff give an account of the wax-glands of this Homopterous insect 

 of Ceylon and India. The larvas secrete remarkable silk-like ribbons, 

 which are inserted in the end of the abdomen. In the adult there are 

 no abdominal tufts, but the end of the body, the margins of the wings, 

 etc., are usually covered with white flakes. The minute structure of 

 the glands is described in detail. 



Mouth-parts of BlattidaB.J — Joseph Mangan finds that there is need 

 for more careful investigation of the much-studied mouth-parts of cock- 

 roaches. He contributes some fine figures of the hard parts of Peri- 

 planeta australasice and their musculature, and discusses the theoretical 

 interpretations suggested by Verhoeff and Hansen. He notes, for 

 instance, that elongated plates at the free tip of the hypopharynx may 

 represent a pair of maxillulas fused with the tongue. Just below the tip 

 of the lacinia there is a singular process, which is mentioned by Rolleston, 

 but not recorded on any drawing known to the author. The maxillary 

 palp is most plausibly homologous with an endopodite. 



* Amer. Journ. Anat., vii. (1908) pp. 469-87 (5 figs.). 



t Bull. Soc. Vaud. Sci. Nat., xliii. (1907) pp. 549-63 (7 pis. and 4 figs.). 



% Proc. R. Irish Acad., xxvii., B, i. (1908) p. 1-10 (3 pis.). 



2 q 2 



