992 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and compares his accounts witli those of Leydig and Weismann, 

 which he partly criticizes. He denies that the larva inverts its 

 pharynx, and cites experiments in defence of his view ; he finds the 

 brush-like processes of the pharynx to be of use in cleansing the 

 oral orifice from undigested food. He makes some additions to Weis- 

 mann's account of the anatomy of the stomach in describing the 

 leaflets, which are covered internally with minute spicules ; the action 

 of these organs remains to be detected ; like the gizzard, they dis- 

 appear during the change from the larval to the pupal stage. 



Structure of the Wings of Vesicating Insects.* — M. Beauregard 

 remarks that vesicating insects present a remarkable softness of the 

 elytra and of the integument in general. The explanation of this 

 fact is not to be found in the chemical but in the histological cha- 

 racters of the wings. Between the two layers, which are connected 

 at their edges by chitin, there is a somewhat considerable space, and 

 the two layers are connected by chitinous pillars, which are thin and 

 delicate, and merely form supports, whereas in other insects the 

 chitinous layers are thick, the pillars large and numerous, and the 

 spaces almost nil. 



Larvae and Larva-cases of some Australian Aphrophoridse.f — 



Mr. F. Eatte describes the larval state of some small species of 

 Ehynchota, belonging to the genus Ptyelus, nearly allied to Aphro- 

 pliora. An examination of their larva-cases and of some of the larvae 

 discloses a feature probably quite new. 



The cases of these insects, unlike those of insects generally, are 

 true shells, containing at least three-fourths of carbonate of lime, 

 some being helicoidal and others conical, resembling some fossil and 

 recent Serpulse. The conical shells are fixed on the branches (gene- 

 rally a little above the insertion of a leaf) of some species of 

 Eucalyptus, the opening turned upwards and the larva being placed 

 in it with the head downwards. In the helicoidal shells the insect 

 lies horizontally for the greater part of its larval life. In both 

 instances it follows that the larva instead of presenting its head at 

 the entrance of its shell, like a mollusc, presents its hind region. 

 It introduces its suctorial apparatus into the bark of the stem 

 and sucks the sap. For this purpose the shell is provided with a 

 longitudinal slit. It emits from time to time by its anus a drop of 

 clear water at the entrance of the shell. The lime which enters into 

 the composition of the shell is evidently provided from the sap of the 

 tree. 



S. Arachnida. 



Muscular and Endoskeletal Systems of Limulus and Scorpio.J — 

 Prof. E. Eay Lankester, with the assistance of Mr. W. B. S. Benham 

 and Miss E. J. Beck, has another contribution to our knowledge of 

 Limulus, especially as compared with Scorpio. It was to be expected 



* Journ. Soc. Scientifique, 1. (1885) p. 209. 



t Proc. LiuD. Soc. N. S. Wales, ix. (1885) pp. 1164-9 (2 pis.). 



: Trans. Zool. Soc. Lend., xi. (1885) pp. 311-84 (12 pis.). 



