500 SUMMARY OF CURRENT RESEARCHES RELATING TO 



oval, and is connected with the thoracic ganglion by means of a long 

 thin cord. From this ganglion spring three pairs of nerves, of which 

 the first and second pairs branch out in the fifth and sixth segments of 

 the abdomen, while the last pair branch out in the last segment of the 

 abdomen and in the rectum. 



This nervous system is as curious as that of some Coleoptera 

 (Bhizotrogus solstitialis, Serica brunnea) and some Hemiptera (Hydro- 

 metra lacustris), as it has no ganglion infra-cesophageum. 



Insects which injure Books. — Professor A. Liversidge, of Sydney, 

 sends us some specimens of Lepisma saccharina, and points out that 

 "in Blades' 'Enemies of Books,' 3rd ed. (1881) pp. 61-3, he refers to 

 the description of a book-worm in Hooke's ' Micrographia ' (1665), 

 and rather makes fun of the figure and description there given — 

 ' certainly R. Hooke, Fellow of the Eoyal Society, drew somewhat 

 upon his imagination here, having apparently evolved both engraving 

 and description from his inner consciousness.' 



People living in New South Wales and other of the warmer 

 parts of Australia can, however, bear testimony to the accuracy of 

 Hooke's statements and drawing. The insect figured in the ' Micro- 

 graphia ' abounds here amongst books and papers, and is wonderfully 

 destructive to them. It does not do so much harm to books as it does 

 to loose papers, maps, labels, &c, as it cannot well get in between 

 the closely pressed leaves of a book, and it is on this account that the 

 loose edges of piles of MS., bundles of letters, &c, suffer so much 

 more than the central portions ; writing paper, too, probably contains 

 much more attractive matter in the way of size, &c. 



With this I enclose some scraps of paper showing the ravages of 

 the insect {Lepisma), and also some of the ' silver fish ' themselves, 

 by which name they are commonly known here and also in India, 

 whence I understand the name ' silver fish ' originated. 



The destruction of labels is a very serious one, as the identity 

 of a specimen may very soon be lost. The labels enclosed have only 

 been written about fifteen months, and some hundreds have thus been 

 rendered totally useless. In future it will be necessary to saturate 

 the labels with a poison, such as corrosive sublimate. 



At times I have thought that, perhaps, the ' silver fish ' instead 

 of doing harm may be doing good — for wherever they are found we 

 are likely to find pseudo-scorpions (chelifer), and it may be that the 

 former prey upon the latter ; though I think not." 



Formation of Galls.* — M. W. Beyerinck finds that " galligenesis " 

 affects a portion of the vegetal tissue, which becomes altered in 

 character, and may then be known as galliplastema ; the galligenetic 

 influence is due to the larvae and not to the hymenopterous parent. 

 The phenomenon of formation of the galls is absolutely indepen- 

 dent of the lesions which the deposition of the eggs causes in the 

 living tissues of the plant. Direct contact between the animal and 

 the plant is not necessary for the production of the galliplastema ; 

 there may be a layer of dead cells, or even the covering of the egg 



* Kev. Internat. Sci. Biol., ix. (1882) pp. 373-4. 



