580 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Development of Caddis-worms.* — A. J. Siltala gives a very welcome 

 study of the post-embryonic development of Tricnoptera. In family 



after family he describes the two stages in larval development ; he dis- 

 cusses in particular the chitinous integumentary processes, the mouth- 

 parts and antennas, and the respiratory organs ; and he deals also with 

 the physiological and ecological aspects : the locomotion, nutrition, 

 respiration, moulting, and the making of the protective cases. 



Regeneration of Segments in Ephemerid Larvae. f — S. Oppenheim 

 has experimented with larvae of ( 'loeon dipterum, removing the last seg- 

 ment. Most die in 3-5 days, but 12 out of 532 regenerated the lost 

 segment. Between the second and third moult the regenerated piece 

 approximated to the normal shape. In a few cases he succeeded in 

 getting some regeneration after removing two and three segments. 



Mallophaga of the Kea. J — Vernon L. Kellogg finds that the Kea 

 {Nestor notabilis) has some troubles of its own. It bears three species 

 of Mallophagan parasites, Lipeurits circumfasciatus Piaget, var. Jcea 

 Kellogg, Colpocephalum setosum Piaget (also found on the vulture), and 

 Mmopon fulvofasciatum Piaget var. kea Kellogg (the same species occurs 

 on Buteo vulgaris). It is curious that two of the three parasites should 

 have been previously recorded not from parrots but from birds of prey. 



Germ-cells and Embryology of Aphids.§ — Gr. W. Tannreuther 

 describes the development of certain Aphids, with special reference to 

 the behaviour of the two kinds of eggs during maturation, and the 

 relation of the sexual to the parthenogenetic individuals. The life- 

 history of two of the species chiefly studied, Melanoxanthus sal iris and 

 M. salickola, is described in detail. In regard to the germ-cells, the 

 author finds that the somatic number of chromosomes, six, is a generic 

 characteristic. The chromosomes vary in size, four large and two 

 small. This number and size of chromosomes is constant in both the 

 sexual and parthenogenetic forms. In the male, the six univalent chro- 

 mosomes ithite end to end in pairs in the early prophase of the first 

 spermatocyte division, and form two large and one small bivalent chro- 

 mosome. There is a short resting period between the first and second 

 spermatocyte division. Each spermatid receives three chromosomes, 

 two large and one small. No accessory chromosome is present. The 

 first division separates bivalent, and the second divides univalent 

 chromosomes. The six chromosomes at the beginning of the growth- 

 period in the sexual ova pass into the resting stage, and the reduced 

 number, three — two large and one small— are found in the prophase of 

 the maturation division. Both polar bodies are formed before the 

 germinal vesicle breaks down. Fertilisation occurs at the time of de- 

 position, and the male and female pronuclei unite shortly after the 

 eggs are deposited. Both polar bodies remain within the egg-cytoplasm 

 near the periphery, and disappear before the beginning of cleavage. 



* Zool. Jahrb., ii. supp. 9 (1907) pp. 309-626 (5 pis. and 20 figs.). 



t Zool. Anzeig., xxxiii. (1908) pp. 72-7 (6 figs.). 



J Psyche, 1907, pp. 122-3. 



§ Zool. Jahrb., xxiv. (1907) pp. 609-42 (5 pis.). 



