HA RD WICKE' S SCIENCE- G OSSIP. 



67 



The thorax is generally stout, and the abdomen 

 comparatively long, being extremely slender in 

 certain families. At the apex of the latter are situated 

 two pairs of forcipated, or leaf-shaped appendages, 

 varying considerably in form in the different species 

 and also to a less degree in the sexes. 



The wings are elegantly veined or reticulated, and 

 both fore and hind pairs are equal in size. In repose 

 they either rest horizontal or erect, the posterior pair 

 never being folded.* 



The metamorphoses of the Odonata, as has been 

 previously mentioned, are incomplete or imperfect ; 

 that is, the larva differs very slightly in structure from 

 the imago or perfect insect, and the pupa is lively 

 with the exception of a very brief period previous to 

 undergoing the final stage. 



Dragon-flies are amphibious creatures, in all the 

 earlier stages of their existence they reside in the 

 water of streams, ponds, and lakes. No species has 

 hitherto been discovered to inhabit salt water, though 

 certain kinds have been found in brackish water, f a 

 very important fact indeed, since it may prove 

 eventually to be a valuable clue towards a solution of 

 the origin of the Odonata and likewise to the elucida- 

 tion of their evolution. One of the most wonderful 

 facts in connection with the economy of these highly 

 specialised insects is their mode of breathing in the 

 water, which is not (in the Libellulina) by means of 

 branchiae as is the case with many other aquatic 

 insects, but is internal — but we will reserve the 

 discussion of this for another chapter. In the next, 

 we will commence to consider the metamorphoses of 

 the Odonata in detail. 



{To be continued.) 



SCIENCE-GOSSIP. 



" My Telescope " is the title of a little astronomi- 

 cal work by "A Quekett Club-Man," whose kindred 

 volumes on the microscope have been so successful. 

 It will be published in a few days by Messrs. Roper 

 & Drowley. 



Silk -worm Cocoons. — It would be interesting to 

 know whether the brown silk, exhibited by Mr. E. B. 

 Poulton and recorded on page 21, is liable to become 

 the usual bright yellow on exposure to light for a long 

 period.—^. C.D.B. 



Death has been very busy lately in the ranks of the 

 foremost scientific men of all countries. Many names 

 will henceforth be removed from the lists of living, 

 to those of historic, celebrities. Among them are the 



* For further and more complete particulars of structural 

 characteristics, see Westwood, J. O., "An Introduction to the 

 Modern Classification of Insects," 2 vols., 8vo. London, 1840. 

 Libellulida^, vol. ii. pp. 34 _ 4°- 



f See Kingsley, John Sterling, "The Standard Natural 

 History," 4 8vo. Boston, 1884. Odonata, vol. ii. p. 147 (Uhlers 

 quoted). 



following : — Prof. Hayden, late director of the U. S. 

 Geological Survey, at the comparatively early age of 

 fifty-eight ; Dr. Asa Gray, the distinguished American 

 botanist, at the riper age of seventy-seven ; Mr. 

 Waterhouse, late keeper of the Geological Department 

 of the British Museum, in his seventy-eighth year ; 

 Professor De Bary, the celebrated botanist and fungo- 

 logist, at the age of fifty-seven j and others of less 

 note. 



Dr. G. J. Romanes has been elected to the Chair 

 of Fullerian Professor at the Royal Institution, and 

 intends occupying the whole of his three years of 

 office delivering lectures on " Before and After 

 Darwin." 



Mr. J. E. Harting has been appointed Assistant 

 Secretary to the Linnean Society in place of Dr. 

 Murie. 



There is nothing new under the sun ! The other 

 day there was dug up among other long-buried curios 

 at Pompeii, a case containing a complete set of 

 surgical instruments, many of which are said to be 

 closely similar to those used at the present day. 

 The medical art is evidently both very ancient and 

 very conservative. 



It was the last French war which originated the 

 beet-sugar manufacture in France. The sugar-loving 

 Frenchmen could not get it from the West Indies. 

 Within a very short period a sugar beet was 

 artificially selected, and in our time this beet has so 

 developed its saccharine qualities that it produces 

 nearly twice as much sugar as it did in Napoleon's 

 time. But the Germans also took up beet-sugar 

 manufacture, and they have beaten the French even 

 on this field of war. Thanks to their improved 

 methods of extracting the sugar and molasses from 

 the beet-root, they can now obtain nearly n|lb. from 

 100-lb. weight of beet, so that the cost of the sugar is 

 now reduced to id. per lb. 



A well-KNOWN New York physician has just 

 published the sort of discovery which Lord Lytton 

 would have made a novel out of. An aged Polish 

 count, formerly professor of languages and a famous 

 Oriental scholar, died in the hospital, and Dr. 

 Rookwood had occasion, in conjunction with other 

 experts, to make a microscopical examination of a 

 certain part of the cerebrum. They noticed a 

 peculiar set of markings, which took the form of 

 Egyptian and Chinese hieroglyphics. These were 

 amplified to a magnitude of 3000 diameters, and 

 the results shown to another Oriental scholar, who 

 declared them to be true characters in the Ethiopic, 

 Syriac, and Egyptian languages. Dr. Rookwood 

 suggests that his discovery will lead to extracting 

 from the dead their literary achievements as well as 

 their "suppressed opinions." 



