ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 74ii 



Structure and Pliylog«netic Significance of Embryonic Abdominal 

 Appendages in Insects.* — Prof. V. Graber remarks that tliere are two 

 facts which seem to show that the present meropodoiis Insects are derived 

 from forms that had appendages on all their trunk-segments. The 

 first of these is the presence of ai)pendages on all the segments of the 

 lower apterous Insects, and the other is the presence of ventral abdomi- 

 nal appendages in the embryos of the most various kinds of Insects. 

 It is, however, to be noted that these embryonic appendages often 

 disappear before tbeyhave passed beyond an altogether indifferent stage, 

 and that, therefore, they tell us nothing as to the nature of the structures 

 which have disappeared ; the appendages on the first segment lead us 

 to sup{)ose that they are the remains of myriopodiform legs. The 

 ventral appendages in Stenohothrus have a large lumen, and the cells of 

 their outer wall are of enormous size ; the coagulation found on making 

 sections seems to be partly, at least, secreted by cells of the ventral 

 saccules which are not limited by any chitinous membrane ; or, in other 

 words, these appendages appear to be truly glandular. A number of the 

 statements aucl arguments used by Cholodkowsky in his recent memoir 

 are traversed. 



Markings of Lepidoptera in the Genus Ornithoptera.t — Dr. C. 

 Fickert has investijated this subject with great minuteness, comparing 

 species with species, and variety with variety, in intricate details of 

 shades and dimensions. He believes that the varieties and sj)ecies can 

 be arranged in a series so orderly, that the notion of fortuitous variation 

 is excluded, and that of progressive constitutional growth, as emphasized 

 by Eimer, confirmed. In Ornithojjtera priamus, to which special atten- 

 tion is paid, the author finds a species in process of rapid phyletic 

 progiess. Some of its varieties — 0. arruana, richnondia, priamus, and 

 hjdius are now constant ; others, e. g. 0. pegasus, are still very unstable 

 in both sexes ; while in others, e. g. 0. crcesus, the males are constant, 

 but the females are unstable. Specific change is like varietal, the direc- 

 tions in both are few and definite, separation in space has been of much 

 importance, and the females conserve longest the original characteristics. 

 The interesting fact is pointed out that the caterpillar stage may some- 

 times in its markings advance beyond what is attained by the adult 

 butterfly, the progressive variability being in such cases apparently 

 predominant in one phase of life. The paper affords interesting corro- 

 boration of Elmer's results. 



Spermatogenesis in Lepidoptera.^ — Herr G. Platner finds (1) that 

 the centrosoma of the spermatocyte forms the apical portion of the 

 spermatozoon, (2) that the rest of the head is formed solely from the 

 chromatin of the spermatide nucleus, and (3) that the accessory nuclear 

 body arising from the substance of the nuclear spindle (in the sperma- 

 tocyte) is modified as a sheath for the axial filament of the spermato- 

 zoon. 



Following a now well-established terminology, Platner distinguishes 

 — (1) the last generation of cells as spermatides, (2) the penultimate as 

 spermatocytes of the second order, (3) the antepenultimate as sperma- 

 tocytes of the fii-st order, and (4) previous generations of cells as 



* Biol. Centralbl., ix. (1S89) pp. 355-63. 



t Zool. Jahrb., iv. (1889) pp. 692-770 (3 pis.). 



I Arch. Mlkr. Anat., xxxiii. (1S89) pp. 192-2D3 (1 pi.). 



