ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 199 



leaf-sheaths of various aquatic plants, and feed on the sap which flows 

 out from bitten parts. The larval period lasts for three months, and 

 there are six moults. The ordinary stigmata are closed till the penulti- 

 mate moult, and the final form is not assumed until the last moult. 

 Respiration is discharged by the special terminal " Hakchen-stigma " 

 which has a closing apparatus. The imago of Macroplea remains per- 

 manently in the water. It does not use atmospheric gas, but what it gets 

 from plants. This is collected by a multitude of hairs on the antennae. 



Post-embryonic Development of Stratiomydse.* — Simeon Jusbasch- 

 janz has studied larvae and pupae of Odontomyia and Stratiomys, 

 with special reference to the thoracic imaginal disks, the mesoderm of 

 the appendages, the head-disks, the metamorphosis of the thoracic 

 muscles (in which the new formation is wholly due to the activity of the 

 imaginal myoblast-mass), and the gullet (with its masticatory specializa- 

 tions). Two peculiarities are the thoracic hypodermis-primordia and 

 the secondary formation of a peripodial space. 



Brain of Lepisma. f — Otto Bottger has done a very useful piece of 

 work in making a thorough study of the brain of Lepisma saccharina, 

 a welcome contribution to the comparative anatomy of the insect's 

 brain. Lepisma (the silverfish not uncommon in houses) has a quite 

 peculiar brain, and shows some parts which have not been observed as 

 yet in other insects. The characteristic peculiarities are : (1) the 

 spherical shape of the mushroom-like bodies ; (2) the large cell-mass 

 which lies behind these — the quite peculiar grape-like body ; (3) the large 

 size of the olfactory lobe and the small size of the optic lobe ; and (4) 

 the strength of the labro-frontal nerve and its origin from a particular 

 lobe on the oesophageal commissure. 



Study of Corixa.J — J. Hagemann has made some very interesting 

 observations on Corixa, both in its larval and its adult stages. He 

 describes the respiration at successive stages and the structure of the 

 stigmata. A new tympanal organ is described, which occurs in close 

 association with the second stigma. It probably serves for the percep- 

 tion of the notes (of two kinds) which the males produce by rubbing 

 their tarsi against the striated rostrum. The abdominal glands of the 

 larvae are described, and the asymmetry of the male abdomen is discussed. 



&■ Tffyriopoda. 



Study of Polyxenus.§ — Georg Reinecke has made an interesting 

 study of Polyxenvs lagurus, a beautiful little Millipede, with particular 

 reference to its mode of life, and its respiratory, alimentary, and repro- 

 ductive systems. There is relatively little known of the minute structure 

 of the Pselaphognatha to which Polyxenus belongs. 



The creature lives under bark and the like in moist places. It feeds 

 on wood and vegetable matter. Its alleged destruction of Phylloxera 



* Jen. Zeitschr. Naturw., xlvi. (1910) pp. 681-736 (3 pis. and 7 figs.). 



t Tom. cit., pp. 801-44 (2 pis. and 6 figs.). 



% Zool. Jahrb., xxx. (1910) pp. 373-426 (2 pis. and 2 figs.). 



§ Jen. Zeitschr. Naturw., xlvi. (1910) pp. 845-96 (6 pis. and 21 figs.). 



