38 



HARDWICKE'S SCIENCE-GOSSIP. 



a rule the pigment is most thickly deposited in the 

 upper third of the scale. It is sometimes altogether 

 absent from the lower third. But it is occasionally 

 pretty equally distributed over the whole scale, and 

 down into the foot-stalk, 



In a broken scale of the Argynnis Adippc the dark 

 lines of pigment at the seat of the fracture appeared 

 broken up into small irregular particles (fig. 37). 

 These had no definite form, but were mostly angular 

 in outline. It is not probable that these were the 

 ultimate molecules of pigment. 



In examining the scales from the wings of Lepido- 

 ptera which had been decolorised by chlorine, the 

 lines appeared to be unchanged in their outline 

 although they were not nearly so dark as before. To 

 the naked eye the wings themselves had a translucent 

 membranous appearance. 



Many of the bright and lustrous tints seen in Lepi- 

 doptera are not due to pigment, but are produced by 

 the surface and edges of the scales, which have the 

 power of absorbing some of the prismatic colours and 

 reflecting others. 



MICROSCOPY. 



A Live-box. — I send you a drawing of a live-box, 

 which might be of interest to your readers. A, A are 

 glass slips ; B, B are brass bands ; c, c are wedges ; 



Fig. 39. — Improvised live-box. 



Fig. 40. — Thick indiarubber ring for live-box. 



D is an india-rubber ring. The advantage gained by 

 using this form of live-box is that it is thoroughly 

 water-tight, and that it can be taken to pieces, 

 cleaned, and put together in a very short space of' 

 time. — Albert Smith. 



Newcastle Microscopical Society. — A general 

 meeting of the North of England Microscopical Society 

 was lately held. The following officers are appointed 

 for the ensuing year : — President, Professor G. S. 

 Brady, Mr. M. H. Robson, and a committee of ten. 

 The inaugural meeting was held on Wednesday, 

 January 8. This society has been formed to meet 



a long existing want amongst microscopists, who 

 will now have an opportunity of meeting at regular 

 intervals with excellent accommodation, and under 

 the direction of an organised society, which since the 

 dissolution of the Newcastle-upon-Tyne Microscopical 

 Society in 1864 they have not possessed. 



The Pygidium of Insects. 1 — At a recent meeting 

 of the Royal Microscopical Society, Mr. Henry Davis 

 read a paper on this subject, in which he showed 

 that the organ which went by this name had its re- 

 presentative in the Neuroptera, and other groups of 

 insects, as well as in the flea, and the lacewing fly. 

 He regarded the pygidium as a special organ of sensa- 

 tion for conveying to the insect an intimation of the 

 presence of dangerous enemies. 



ZOOLOGY. 



Birds Migrating. — In compliance with your 

 correspondent's wish, I write to tell you that I have 

 noticed here (Oporto), during August, a migration 

 similar to that mentioned in Science-Gossip of 

 October I. The night of August 26 was dark and 

 hazy, the wind light and from the south or south-west. 

 I heard more particularly from eight to nine o'clock 

 P.M. fluty querulous notes from birds flying over my 

 house from north to south, and not very swiftly. 

 There appeared to be only one species, and the notes 

 were in sets of four — tchoo-hoo- 

 hoo-hoo. It was impossible to see 

 the birds, although I tried repeat- 

 edly when some must have passed 

 close over the house, which is on 

 a hill to the north side of the 

 mouth of the Douro, and about 

 eight minutes' walk from the sea. 

 They seemed to pass in small flocks, keeping up a 

 constant calling and answering. The notes were 

 heard chiefly from eight to nine, but continued less 

 frequently till late on in the night. I believe that 

 hundreds, if not thousands, must have passed during 

 that night. They had been heard some nights pre- 

 viously also. It would be interesting to learn the 

 species to which these migrants belonged. That 

 they were some species of large sandpiper I feel 

 pretty certain, and I suspect they were red-shanks. 

 Can any of your correspondents suggest how this 

 could be ascertained with certainty ? I noticed some 

 days previously numbers of red-shanks, ringed dotterel, 

 whimbrel, turnstones, and some smaller sandpipers 

 on the banks of the Douro. Most of these were 

 late arrivals from the north. Some possibly may 

 have passed Maidstone ! I suppose it would be 

 difficult to devise some way of catching them while 

 flying over at night? Could the phonograph be 

 available for comparing the notes of birds ? This is 

 an interesting locality for observing the migration of 



