340 



NA TURE 



[lliliRUAKY 7, 1S95 



The ir.tro i ictory chanters are very good, and the 

 woodcuts are c'e\r an 1 instructive, especially that of the 

 neuration nf a butterfly, on p. 9. We cou'd have wished 

 that Mr. Furneaux hid had space to treat of such im- 

 portant suSjicts as neurition and the scaling of the 

 wings m 're fully. The early stages of Lepidaptera are 

 also discussed and illustrated ; and we notice that our 

 author ca'ls the head of a caterpillar the "first seg- 

 ment." We know that some hypercritical authors object 

 to the held of an insect being called a segment, because 

 it is morph ilogically considered to be made up of so 

 many "simites." But to refuse to allow the head of an 

 insect to be called the first segment (in the case of cater- 

 pillars, at lea^t) appears to us as absurd as it would be 

 to object to the skull being spoken of collectively, because 

 it is morphologically regarded as composed of a number 

 of mod fied verlebr.x. On the other hand, we think that 

 Mr. Furneaux has been injudicious in calling the five 

 membranous pairs of legs of a caterpillar " claspers,'' 

 a term properly applicable to the last pair only. We 

 think the usual distinction made between the last 

 pair and the others should be preserved in speaking 

 of them, though the term by which the other legs are 

 generally known (prolegs) is perhaps not quite correct. 



The directions for collecting and preserving appear 

 to have been written by an experienced practical col- 

 lector, with his heart in his work. However, when insects 

 are set tlat. the groove is generally made deeper than is 

 shown in the illustrations on p. 123. The advice to start 

 at once with a cabinet, spaced out for all species, may be 

 very good for those who can afford to buy a large cabinet 

 offhand ; but many of Mr. Furneaux's readers will cer- 

 tainly find it too costly, and we fear that any beginner who 

 commences in such a manner will find his patience ex- 

 hausted at his slow progress, and might give up the study 

 of insects prematurely in disgust. 



No technical characters are given for species, genera, 

 or even families ; and, strangely enough, the .Seraphims 

 \Lobophora) are said to differ from the I'ugs {Eupi- 

 thtcia) by their" covering their hind-wings when at rest '' ; 

 no mention being made of the curious appendages to the 

 hind-wings of the males in Lobophora, which gives them 

 the appearance of having six wings, and has suggested 

 the name of " .Seraphims." 



Generally speaking, however, the accounts of the 

 \arious species discussed (all the butterflies and a good 

 series of representative moths, at least among the Macro- 

 I.cpidoptera) are very good. Mere and there, however, 

 we meet with a doubtful statement, as that " the Dlack- 

 veined White is hardly to be distinguished from the 

 Common Large White on the wing." Those accustomed 

 to see both would hardly confound them, nor would the 

 former frequent open ground at a distance from trees. 



The numerous woodcuts are of unequal merit, but 

 a fair standard of excellence is maintained throughout, 

 and most of them arc easily recognisable. The coloured 

 plates, though recognisable too, are, we regret to say, not 

 up to the standard of the woodcuts. Sometimes the 

 colour is inaccurate, as in the case of the Purple 

 Kmpcror, which has been represented as lilac rather 

 than blue. It is, of course, a difficult insect to figure, 

 but has been represented better in many popular bcoks 

 of late years. In the tirst two plates, an attempt has 

 NO. 1319. VOL. 51] 



been made to throw up the colour of the insects (mostly 

 whiles and yellows) by shading. This has given rise to 

 the appearance of an ugly smoky rim round the figures: 

 and the experiment has been wisely abandoned m the 

 remaining plates. We regret this the more, as the 

 desired eflTect has been admirably attained by using a 

 tinted background in Prof. Aurivillius' recent work on 

 the butterflies and moths of Northern Europe; and we 

 should like to see this improvement introduced into 

 other books of a similar kind. 



W. F. KiRBY. 



OUR BOOK SHELF. 



Die Resultate der Aetzmethode in der krystallograph- 

 ischcn Forschuns;, an einer Rcihe von kryslallisirtett 

 Korperndar^^estellt. Von Dr. H. H.iumhauer. Mit 21 

 Texifiguren und einer iMappe mit 48 Mikrogrammen 

 auf 12 T.ifeln in Lichldrnck. Pp. 131. (Leipzig: 

 Wi;helm Engelmann, 1S94.) 



It has long been known that the action of a reagent 

 upon a smooth plane surface of a mineral substance may 

 reveal details oi structure previously invisible, and that 

 such a mode of investigation has been extiemely useful 

 in the case of meteoric iron ; indeed, the method is 

 particularly valuable in that case by reason of the fact 



th:it the structure thus revealed is dilleieni fiom the 

 structure of terrestrial iron. 



The researches of Leydolt, Baumhaucr, and others, 

 have shown us that the figures produced by reagents on 

 the faces of the crystals which aie met with among 

 minerals, or are artificially prepared by the chemist, 

 though dependent on the kind and strength of the re- 

 agent, are \el characteiiscd by a symmetry which con- 

 forms with'that of the crystalline structure ; further, the 

 etched figures serve to indicate by their forms the par- 

 ticular kind of symmetry (holosymmetry, hcmisymmetry 

 tctartosymmetry, twinning) belonging to the crystalline 

 structure, in many cases where other characters, physical 

 or morphological, are insufficient for the purpose ; they 

 are especially useful in the investigation of isomorphism. 



The etched figures can be observed, for instance, 

 in the case of a crystal of which the opacity renders 

 investigation by means of transmitted polarised light 

 impossible ; and, even in the case of a transparent 



