any par- 



ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 179 



Sex-Determination in Bees.* — Ferd. Dickel has made twelve ex- 

 periments which seem to him to support his somewhat heretical views in 

 regard to the sex-determination in bees. He believes that " drone-eggs " 

 are fertilised ; that drones can be reared from " worker-eggs," and vice 

 versa ; that all the eggs laid by a normal queen are fertilised ; that the 

 ripe ovum has in itself only the potentiality of masculinity ; that the 

 sperms bring in the potentiality of femakmess, whether of workers or 

 queens ; and that the workers produce a " sex-determining " and a 

 " volume-determining " substance which settles the destiny of a 

 ticular egg which they handle. 



Parthenogenesis in Porthesia.f — Tad Garbowski reports the occur- 

 rence of indubitable parthenogenesis in Porthesia similis, which was 

 reared from a pupa-case and kept in isolation. It laid eggs in three 

 batches, and died. All the eggs hatched into active caterpillars. 



Sleeping Sickness of Silkworms.^ — J. Bolle and M. Richter find 

 that this disease is in no wise due to the micro-organisms of the mulberry 

 leaves. Six species of bacteria and two yeasts were obtained from the 

 leaves, but inoculations of cultures failed to induce any Schlafsucht in 

 the silkworms. 



Ants from the Andaman and Nicobar Islands.§ — A. Forel reports 

 on a collection, which shows that the ants of these islands are related to 

 those of India and of Indo-China, and include some peculiar forms. 

 There has been an invasion from both east and west. Forel analyses 

 the collection into 9 local forms, 5 occidental, 7 oriental, 3 shared with 

 Hindustan and Burmah, 10 both oriental and occidental, and 4 cosmo- 

 politan — 38 in all. 



Development of Ovary of Polyxenus lagurus De Geer.|| — A. 

 Lecaillon finds in newly-hatched larvre two distinct ovarian primordia, 

 each consisting of a small aggregate of oogonia surrounded by an en- 

 velope of flattened cells, and including small cells destined to form the 

 follicular elements. In a short time, however, the two oogonial masses 

 unite and form a single ovary- — unique among insects. The further 

 history is followed, and noteworthy is the appearance in the cytoplasm of 

 the young ova of a special eytochromatic substance, which is probably a 

 differentiation concerned with the elaboration of assimilable substances. 



Peculiar Aphid.T — Alice L. Embleton describes Ceratajjnis latanim, 

 which has been called by more than half-a-dozen names. In Britain the 

 species seems now to occur in only one form, the apterous female, 

 which reproduces parthenogenetically in an uninterrupted manner. The 

 occurrence of the winged female was, however, noted in England for one 

 or more seasons a quarter of a century ago. It is suggested that the 



* Arch. Ges. Physiol., xev. (1903) pp. 66-100. See Zool. Centralis, x. (1903) 

 pp. 740-1 . 



t Zool. Anzeig., xxvii. (1904) pp. 212-4. 



X Zeiteehr. Landw. Versuchswesen Osterreich, 1903, p. 287. See Centralbl. Bakt. 

 Parasitenk. I 19 Abt, xxxiii. (190:!) pp. 73f>-6. 



§ Revue Suisse Zool., xi. (1903) pp. 399-411. 



|| Comptcs Rendus, cxxxvi. (190:'.) pp. 1691-3. 



i Journ. Linn. Soc. (Zool.), xxix. (1903) pp. 90-107 (1 pi.). 



