422 RECORD OF CURRENT RESEARCHES RELATING TO 



orders of the Lepidoptera, tlie Hymenoptera, and the Diptera, of such 

 a nature as to show that the proposed reduction in the limits of the 

 latter segment is in strict accordance with what might be expected 

 from the abortion of the posterior wings as organs of flight. Inci- 

 dentally the question of the limits of this segment in the Hymenoptera 

 is discussed, and support given to Andouin's views on this subject by 

 reference to Packard's figures of the development of the humble bee, 

 and to the collateral structure of the Coleopterous thorax. 



The evidence of developmental change is adduced to support the 

 prothoracic character of the humeri. It is also stated that the 

 square plate lying between the halteres of the crane-fly, which is 

 seen to correspond with the posterior wall in question of the blow- 

 fly, underlies the mesothoracic integument of the former insect, and 

 must therefore itself be regarded as mesothoracic. 



Lastly, the importance of the muscular system of insects is urged 

 as an accessory source of information in disputed questions as to the 

 relations of their external parts. It is contended that in no known 

 instance are the great longitudinal muscles of two segments merged 

 into one homogeneous mass, as must be the case if the views hitherto 

 accepted upon this subject be maintained, and that the same argu- 

 ments apply to the lateral vertical muscles, which are in no other 

 instance found to pass from the scutum of one segment to the sternum 

 of the next, as here they would be found to do on the same disputed 

 hypothesis. 



Insects which injure Books.* — In a paper read to the British 

 Association, Professor Westwood reviewed the life-history of the 

 insects which destroy books and printed papers, several of which had 

 not been noticed by Dr. Hagen in his address to the American 

 Library Association in July, 1879. 



The caterpillars of Aglossa pinguinalis, and of a species of Depres- 

 saria, often injure books by spinning their webs between the volumes, 

 and gnawing the paper with which to form their cocoons. A small 

 mite (Cheyletus eruditus) is also found occasionally in books kept in 

 damp situations, where it gnaws the paper. A very minute beetle 

 (Hypothenemus eruditus Westw.) forms its tiny burrows within the 

 binding of books. Lepisma saccharina, found in closets and cup- 

 boards where provisions are kept, also feeds on paper, as was seen 

 from a framed and glazed print, of which the plain portion was eaten, 

 whilst the parts covered by the printing-ink were untouched. This 

 habit of the Lepismce has not been previously recorded. The white 

 ants [Termiditcej are a constant source of annoyance in warm climates. 

 Cockroaches are also equally destructive to books. 



But it is the Death-watches (Anohium pertinax and striatum) 

 which do the greatest injury, gnawing and burrowing not only in and 

 through the bindings, but also through the volume, and an instance is 

 recorded where twenty-seven folio volumes placed together on a shelf 

 had been so cleanly drilled through by the larva, that a string might 

 be run through the hole made by it, and the volumes raised by the 



* 'Rep. Brit. Assoc.,' 1879, p. 371. 



