ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 47 



reserve. Rabaud has made some experiments. He put into a narrow 

 tube a Pompilid, Priocnemis variabilis Rossi, and a spider, Mimmena 

 vatia Clerck. The Hymenopteron did not sting. It seemed that the 

 sting could not perforate the abdominal cuticle, for when a smaller 

 spider was supplied, one stab proved sufficient to produce paralysis. In 

 some cases a large spider was dealt with effectively by stinging at a 

 weak spot near the anus or the spinnerets. The paralysis followed 

 .almost instantaneously, although the place of stinging was at some 

 distance froui the nerve centres. Six species of Pompiiids and nineteen 

 species of spiders were tried. The Hymenopteron poison, in the case of 

 spiders at least, diffuses very rapidly. So it is not necessary to sting the 

 ganglia. Indeed the ganglia in spiders are Well protected. The Hymen- 

 •opteron does not seek for places corresponding to ganglia, but for places 

 which are weak spots. Some paralysed spiders lived for eight days. 

 The distinction between dead provender and paralysed provender is not 

 very important. Some victims are vulnerable all over, some have but 

 few' vreak points. There seems to be no seeking for a particular spot, 

 but rather for any vulnerable spot. The position of th,:; ganglia is of 

 sscondary imporiance. 



Cytoplasmic Bodies in Germ-cells of Lepidoptera.* — A. Bronte 

 Gatenby has made a careful study of the cytoplasmic inclusions in the 

 germ-cells of Lepidoptera, e.g. Smerinthns populi, Pieris brassicae and 

 Ori/i/ia antiqua. A little body, the micromitosome, apparently quite 

 -different from chromatin, has been followed from the spermatocyte 

 back into the secondary spermatogonium. It is very probably present 

 in the primordial germ-cell. It has been definitely found in the female. 

 It seems to divide in all divisions, and it appears to be a constant factor 

 in the spermatids of Smerinthus. 



It is shown tliat in early stages the cytoplasmic bodies of the female 

 resemble those of the male. There is a definite period, judged to be 

 .about the beginning of the growth stage, when the subsequent fate 

 ■of the mitochondria in the male becomes different from that in the 

 female. The remarkable formation of chromophobe and chromophile 

 zones in the male mitochondrial body is described, and the author 

 discusses the use of these zones. 



The formation of the macromitosome (middle piece of the sperma- 

 tozoon) from the mitochondria is described. The acrosome of the 

 spermatozoon is formed from several acroblasts, which are traced back 

 to the early growth period of the spermatocyte. The centrosome has 

 been shown to divide in the young spermatid, and one centrosome is 

 probably lost, but definite evidence is not forthcoming. 



Silkworms in Madagascar.! — Fauchere finds that the races of 

 Serii'aria mori introduced from the South of Europe to the centre of 

 Madagascar were originally " monovoltine," i.e. with one generation in 

 the year, and that after about two years they were "polyvoltints," with 

 six generations in the year. Their cocoons were not inferior to those 



* Quart. Journ. Micr. Sci., Ixii. (1917) pp. 407-63 (3 pis. and 5 figs.), 

 t Comptes Rendus, clxv. (1917) pp. 676-7. 



