ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 535 



Study of the Clausilium.*— M. v. Kimakowicz-Winnicki has studied 

 the " clausilium," or closing lid, which is found in some Gastropods. 

 It has been compared by some to the operculum, by others to an 

 epiphragm. He discusses (1) the emergence of the body of the snail 

 from its shell by gas-pressure or by water-pressure ; (2) the structure 

 of the shell in various types ; (3) the making of the epiphragm ; (4) 

 the nature of the true operculum ; (5) the nature of the clausilium 

 apparatus in Alopia and other types. The complicated lamellar struc- 

 ture of the clausilium is described. Its significance is as an accessory 

 apparatus in carrying the shell, which is relatively heavy in proportion 

 to the animal. 



Arthropoda. 



«• Insecta. 



Flies and Disease.f — GL S. Graham-Smith has done a very valuable 

 piece of work in giving a compact account of non-bloodsucking flies in 

 their relation to disease. Many of the non- biting flies frequently walk 

 over and feed on decaying substances and excreta in which disease- 

 producing bacteria may be present ; the flies can carry bacteria on their 

 limbs and bodies for several hours, and internally for several days ; 

 they may thus infect human food and spread infectious diseases. The 

 book is admirably clear and methodical, with effective illustrations and 

 a copious bibliography. Among the subjects dealt with are the follow- 

 ing : the species of non-bloodsucking flies found in houses ; the life- 

 history of the common house-fly ; the habits of flies ; the bacteriology 

 of city flies ; the relation of flies to typhoid, summer diarrhoea, cholera, 

 tuberculosis, anthrax, and some non-bacterial diseases. There is a dis- 

 cussion of myiasis, the diseases of flies, the parasites of flies, the enemies 

 of flies, and the prevention and control of flies. The last chapter sums 

 up the conclusions arrived at. The book is in every way effective and 

 merits great success. 



Urticating Properties of Porthesia similis.J — H. Eltringham has 

 made a further study of the barbed spicules in the anal tuft of Porthesia 

 similis, the spicules to which, as he has already shown, the urticating pro- 

 perties of the female are due. The spicules are apparently identical with 

 those of the larva, in which they occur on every segment except the first 

 and second. In the larva they are borne in tufts on small chitinous 

 papillae, each of these being in direct communication with a double 

 layer of cells. Large branched hairs, and white plume-like structures, 

 looking, to the naked eye, like white spots are distributed all over the 

 body, and apparently serve to hold loose spicules, though they are 

 probably mechanically protective as well. The larva spins a thin tough 

 cocoon interwoven with its own large hairs. Spicules are scattered 

 throughout the looser silk lining the cocoon, and are also arranged in a 



* Zool. Jahrb. Abth. Syst., xxxvii. (1914) pp. 283-328 (1 pi.). 

 f Flies in Relation to Disease: Non-Bloodsucking Flies. Cambridge, 1913, 

 xiv and 292 pp. (24 pis. and 32 figs.). 



X Trans. Ent. Soc. London, 1913, pp. 423-7 (1 pi.). 



