ZOOLOGY AXD BOTANY, MICROSCOPY, ETC. 305 



silk-secreting larva as the source of supply for the thread with which 

 the leaves are bound together into a nest. Bugnion describes the extra- 

 ordinary device employed in drawing two distant leaves together. Several 

 ants, up to five or six, form a chain to bridge the gap, one ant gripping 

 the waist of another in its mandibles. Many such chains may co-operate 

 for hours in drawing two leaves together. 



Ants' Nests.* — A. Forel, in a report on ants from Barbary and from 

 Ceylon, gives an account of the different kinds of nests made by various 

 species of Polyrliackis : — A. Nests of pure silk : (1) a multilocular laby- 

 rinth of pure silk ; (2) a unilocular web on a leaf ; (3) a fine silken tissue 

 lining a unilocular subterranean chamber. B. Nests of silk and debris, 

 of two types. C. Nests of silk and paper, of two types. D. Some 

 doubtful types. 



Regeneration in Insects.f — Viktor Janda has made some remarkable 

 experiments. The larva? of Aeschna are able to re-grow excised antenna?, 

 legs and wing-rudiments. The regeneration goes on slowly in the in- 

 terval between two moults, beneath the old cuticle, without being exter- 

 nally noticeable. Total extirpation of antenna? and limbs is followed 

 by their restitution. The size of the regenerated part is proportional to 

 the time between the operation and the next moult. 



The regenerative capacity in nyniphs of Libellula is much less than 

 in Aeschnids, but in favourable conditions antenna? and limbs may be 

 re-grown. As Child and Young found, the limbs of Agrionid larva? have 

 a high regenerative capacity, and the regenerated tarsi have fewer joints 

 than the normal. 



Thoracic Glands in Caterpillars.^— L. Bordas describes, in illustra- 

 tion of these glands, that found in the caterpillar of Staur opus fag i. It 

 is 6-7 mm. in length, with delicate walls, between the nerve-cord below 

 and the mid-gut above. It extends posteriorly into the abdomen, and 

 narrows anteriorly, without a distinct duct, to open between the first 

 pair of limbs on the first thoracic segment. Bordas also refers briefly to 

 the similar gland in Hadena monoglypha. 



Development of Eggs of Silk-moth.§— C. Yaney and A. Conte dis- 

 tinguish three periods in the development of the "univoltin " egg : (1) 

 the period of the formation of the germinative " bandelette " and the 

 vitelline elements (about five days) : (2) the period of latent life without 

 appreciable embryonic changes (nine months) ; and (3) the period of 

 embryonic construction, in the course of which (about ten days) a cater- 

 pillar is formed. In the first period there is a percentage loss of weight 

 of 2 • 67, in the second of 4 ■ 96, in the third of 7 * 84. The authors have 

 also studied the changes in the content of glycogen and fat. During 

 histogenesis there is a great consumption of glycogen. A contrast is 

 drawn between the development of the " univoltin" and the " polyvoltin " 

 ■eggs of silk-moths. 



* Bull. Soc. Vaud. Sci. Nat., (1909) pp. 369-407. 

 t SB. k. Bohm. Ges. Wiss., xxi. (1909) pp. 1-36 (2 pis.). 

 J Bull. Soc. Zool. France, xxxiv. (1910) pp. 24S-9. 

 § Cornptes Rendus, cl. (1910) pp. 553-5. 



June loth, 1910 y 



