50 



NA TURE 



[NoVEiMBER 1 6, 1899 



pupae, for, though several times alluded to in the text, no 

 description of them is given. Although incomplete, they 

 have given a great impetus to the study of lepidopterous 

 relationships, and it is not every reader that has time or 

 opportunity for turning them up in the Transactions 

 where they appeared. 



The system followed in the Heterocera is that given in 

 Sir George Hampson's " Fauna of British India — Moths," 

 but it has the manifest disadvantage that it does not 

 include two or three of the families referred to. On 

 p. 432 the Prodoxid^e are called a family, though they 

 are clearly intended to be included in the family Tineidae. 

 The use of the same term and ending for an aggregate 

 and' its subdivision tends to confusion. 



Mention of the Lepidoptera leads naturally to the 

 subject of mimicry. So far as facts are concerned. Dr. 

 Sharp brings forward many interesting examples, among 

 them an unrecorded case of the larva of a British bug, 

 Nabis laiivenirts, which mimics an ant, the resemblance 

 being absent in the imago. On the other hand, no 

 reference is made to some of the astounding and com- 

 paratively little known resemblances found among Mem- 

 bracidas. In a species allied to one, Heteronotus trin- 

 odosus^ which is figured, the prothoracic prolongation 

 takes on the form of the entire body of a Hymenopterous 

 insect, so that the Membracid walks about under a mask, 

 or rather, a false body, of the most deceptive kind. 



Dr. Sharp is, however, averse from countenancing 

 any theory of the subject, and his brief account of 

 existing hypotheses is scarcely impartial. In a singular 

 criticism he writes : 



" In endeavouring to realise the steps of the process 

 oi the development of the resemblance we meet with the 

 difficulty that the amount of resemblance to the model 

 that is assumed to be efficient at one step of the develop- 

 ment, and to bring safety, is at the next step supposed to 

 be inefficient and to involve destruction." 



This appears either to involve a non-comprehension or 

 to imply a complete negation of the principles of natural 

 selection ; we do not know whether the latter is 

 intended. 



Of the remaining chapters, that on Diptera is of 

 especial value, on account, not so much of their intrinsic 

 interest, great as that is when once the repugnance to 

 their study has been overcome, as of the help it gives 

 towards obtaining a fair general knowledge of an Order 

 which does not form as a whole the subject of popular 

 monographs, and of which the study is particularly 

 difficult. 



In view of the economic importance of Diptera, it is 

 greatly to be regretted that they do not absorb more of 

 the entomological energy that is wasted in investigating 

 trifles that lead to nothing. With Dr. Sharp's account, 

 it is possible at least to make a start. 



Economic questions, which would have led the author 

 outside the scope of this work, are seldom referred to. 

 With this necessary exception, it is difficult to find a 

 subject of any importance in entomology that is not, in 

 some place or other, touched on more or less fully, and 

 often in the light of independent observation and re- 

 search. Very few forms of real interest are omitted ; 

 but among them is that of Dyscrittna, on the life-history 

 of which Mr. E. E. Green has lately thrown light. 

 NO. 1568, VOL. 61] 



Though his paper was published since the appearance of 

 Vol. V. of this series, reference might have been made 

 in the short appendix to the present volume to his 

 account of this Forficulid larva, which so singularly 

 modifies our knowledge of the earwigs. 



We do not recollect to have before met with the word 

 " exstulpate," which Dr. Sharp is rather fond of using to 

 denote the extruding of an eversible papilla. If it is a 

 latinised form of the German "ausstiilpen," it can hardly 

 be considered as an ornament to the English language ! 



It remains to allude to the illustrations ; these are as 

 good as, though relatively fewer than, those in the pre- 

 ceding volume. The figures of Ornithoptera paradisea, 

 one of the few butterflies selected for figuring, are not 

 successful. Exquisite as this insect, at least the male, is, 

 it does not look well in a woodcut, and these large blocks 

 look coarse and inappropriate on so small a page. 



W, F. H. Blandford. 



A COMPREHENSIVE GEOGRAPHY. 



The International Geography. By Seventy Authors. 

 Edited by Hugh Robert Mill, D.Sc. Pp. xx -f- 1098. 

 With 488 illustrations. (London : George Newnes, 

 Ltd., 1899.) 



SOME forty years ago geography was the most dreary 

 of subjects in school lessons. Its text-books were 

 as arid as the Sahara, lists of names and compilations of 

 statistics ; mere cram, without a single statement or 

 principle which could help the learner to understand the 

 history either of the earth or its inhabitants ; useful as 

 exercise for the memory, but baneful in every other 

 respect. All that has been changed. Geography is now 

 taught as illustrative of principles. Like geology, it is an 

 application of a group of the natural sciences to explain 

 a particular problem, the history of the earth ; differing 

 however, from that in dwelling more on the superficial 

 aspect — the physiography — of our globe, and less on 

 underlying causes or on the remote past. The volume 

 before us is an example of the new method. Though 

 too large for direct use as a text-book in schools, for it 

 consists in all of over iioo pages of rather closely-printed 

 type (which ageing eyes will wish thicker), it will filter 

 down to the classes through the teachers. The first part 

 of the work deals with the principles of geography, the 

 more distinctly scientific aspect of the subject, in a series 

 of excellent essays, which treat of the principles and 

 progress of geography, its relation to mathematics, the 

 making of maps, the plan of the earth and the features 

 of its surface, the ocean, atmosphere and climate, the 

 distribution of life, including the races of man, and the 

 political aspect of geography ; all these subjects being dis- 

 cussed by very high authorities. Each of the following 

 parts is devoted to one of the great divisions of the 

 earth, treating it first as a whole, and then under its 

 minor natural or political divisions, in a series of separate 

 articles, each of which is contributed by " a specialist or 

 recognised authority of high standing." 



To review critically such a book as this demands some- 

 thing like geographical omniscience, to which I have no 

 pretensions ; probably the editor himself is about the 

 only really competent person, and he might be not un- 

 naturally suspected of a certain prejudice. So I have 



