ZOOLOGY AND BOTANY, MIGKOSCOPY, ETC. 49 



organs of both sexes are described, and the life-history and the natural 

 •enemies are dealt with. The adult beetles, after the laying of the eggs 

 from which the first brood will develop, leave the parent galleries and 

 return to the young pine-shoots at the top of the tree with their r.^pro- 

 ductive organs in an exhausted state. On a nutritious diet the organs 

 are restored, and a second egg-laying may follow in a new-made mother- 

 gallery. If the beetles, the parents of the first brood, recuperate in 

 itime, then from their second laying it is possible that a second issue 

 of adults may take place in a calendar year. 



Fertilization in Gnat.* — Monica Taylor notes that the egg-rafts of 

 €ulex pipiens are laid most copiously between 10.30 p.m. and 12.0 p.m. 

 They are also laid between 4.0 a.m. and 6.0 a.m. The process of 

 fertilization is normal. Segmentation begins in less than an hour 

 -after the deposition of the last egg. The chromosome number in the 

 segmenting nuclei is six. A tendency to parasyndesis (side-to-side 

 pairing of homologous chromosomes) is exhibited by the segmenting 

 nuclei. " Parasyndesis probably effects the condition of the chromo- 

 somes in the nuclei of larva, pupa and imago, i.e. is responsible for the 

 presence of the apparently ' haploid ' character of the nuclei in the 

 somatic cells." 



Sugar-cane Leaf-hopper.f — C. S. Misra has made an admirable 

 detailed study of Pyrilla aberrans Kirby, which attacks the sugar-cane, 

 both as a nymph and as an adult. It belongs to the family Fulgoridae, 

 sub-family Lophopinag. Descriptions are given of the eggs, the hatch- 

 ing, the five instars of the nymph, the last moult, and the adult. Account 

 is taken of the few predatory enemies, e.g. occasional ants and dragon- 

 flies, and of the parasitic Chalcididas, Dryinidse, and Stylopidje. Much 

 attention is given to practical questions. The memoir is very well 

 illustrated. 



Bibliography of Human Lice.J— Gr. H. F. Nuttall has compiled a 

 very useful annotated bibliography of the zoological and medical publi- 

 cations relating to the two species of lice {Pedmilus liumanus Linn., 

 1758, and Fhthirus pubis Leach, 1815) infesting man, the part they play 

 in pathology, the prophylactic measures and means of destruction 

 employed against them, their structure, functions, habits, and inter- 

 relations. The bibhography enumerates 639 publications, of which 404 

 have been consulted in the original, 81 in the form of abstracts or quota- 

 tions by other authors, whilst 154 are cited by title only, being either 

 inaccessible or still to be consulted. 



Lice and Disease. § — G. H. F. Nuttall gives a critical summary of 

 the evidence which shows that Pediculus hummius {corporis and capitis) 

 is the carrier of typhus and relapsing fever. Infection with the typhus 



♦ Quart. Journ. Micr. Sci., Ixii. (1917) pp. 287-301 (1 pi. and 1 fig.). 

 + Mem. Depart. Agric. India, v. (1917) pp. 73-133 (6 pis. and 17 figs.). 

 t Parasitology, x. (1917) pp. 1-42. 

 § Parasitology, x. (1917) pp. 43-79. 



Mcirch Wth, 19J8 E 



