1897. SOME NEW BOOKS. 337 



selection the true explanation of mimicry generally would admit that. 

 The similar variation in the same locality of two species of different 

 families, but with the same wing pattern, tells in favour of the direct 

 action of the local surroundings on the markings. And the same 

 view is upheld by the facts as to the geographical distribution of some 

 of the sub-species considered. A variable species may give rise to 

 two similar or closely allied sub-species in widely-separate localities ; 

 the Ceylonese form of a butterfly may be closer to the Indo- Malayan 

 than to the continental Indian form. To invoke land-connections to 

 explain the ranges of sub-species is less reasonable than to suppose — 

 as we know by experiment may be the fact — that similar conditions 

 may induce similar variations in distant localities. But if any sub- 

 species may in course of time develop into a true species, it follows 

 that the same species might arise independently in two or more 

 separate localities. 



Dr. Jordan is content to class himself with the classifiers ; in 

 more than one passage he refers to the work of " us systematists." 

 This memoir shows clearly how much biological importance the care- 

 ful study of species may have, and should encourage his fellow- 

 systematists to fresh and more painstaking effort by reminding them 

 of the many unsolved problems that still lie behind the dry labour of 

 the species-maker. Geo. H. Carpenter. 



British Homoptera. 



The Hemiptera Homoptera of the British Islands. By James Edwards, 

 F.E.S. 8vo. Pp. 271, and ii. plates. London: L. Reeve & Co., 1896. Price 12s. 



This forms a welcome addition to the series of Entomological volumes 

 in course of publication by Messrs. Reeve. Mr. Edwards is the 

 recognised authority on the Homoptera in this country, so that all 

 that comes from his pen on this subject is of value. The plates of 

 details are clear, and will be of great use. There is said to be a large- 

 paper edition with twenty-eight coloured plates, sold at forty-three 

 shillings, but of these plates we cannot speak, as we have only the 

 small edition before us. 



Seriously to criticise a specialist's writings on a very difficult 

 group of insects like the present would be beyond our powers, so we 

 will only notice a few points which appear to us not quite up to the 

 standard of the rest of the book. In the introductory remarks on 

 anatomy, the elytra and wings are treated too much as if they had 

 nothing in common, in fact, a beginner might be led to imagine that 

 a Homopteron had only two wings. This is especially unfortunate in 

 a group where both pairs of wings are sometimes of almost similar 

 texture, as in Cicadetta, and where the term elytra applied to the 

 front wings almost contradicts the name of the sub-order — 

 " Homoptera." We also think that, when considering the wings in their 

 outstretched position, it is misleading to call the apical margin {i.e., 

 that furthest from the body) •' the hind margin." 



In the body of the work we prefer the plan adopted under 

 Liburnia pellucida, where the description of the macropterous form 

 precedes that of the brachypterous, and we think that the tables of 

 species would have been clearer had the specific names been thrown 

 into the margin. 



We may also, perhaps, be allowed to wonder at the numerous 

 species still retained, whose claim to a place in our list rests on a 

 single specimen, often without locality, and to hope that our author 

 may soon be able to clear some of these up, or, if not, to clear them 



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