68 SOME NE IV BOOKS [january 



One other peculiarity of the family may be selected for mention. In about 

 a half of it, certain deviations from the normal type of structure, such as great 

 antennal development, excavation of the forehead or its decoration with hair- 

 tufts, are, so far as is known, diagnostic of the males ; in the other half pre- 

 cisely similar characters when present occur in the females. The line of demar- 

 cation between these halves appears to be arbitrary, and this counter-change of 

 sexual characters in different portions of the same family has given rise to some 

 little confusion, and is not the least interesting of the many biological problems 

 provided by the Bark-beetles. 



To the late Wilhelm Eichhoff, more than to any one else, is due the present 

 state of our knowledge of these insects. By profession a forester, he supple- 

 mented his necessary familiarity with their economy by careful systematic 

 study, and was the first to make a thorough investigation of their oral and 

 antennal structure, and, together with Chapuis, to compile really competent 

 descriptions of exotic species. Eichhoff's Ratio, cfcc, Tomirinorum, published 

 in 1879, is a model of accurate diagnosis, and it is surprising with what ease 

 and certainty the species of the very difficult Tomicinaj are to be identified 

 thereby. 



Two years later Eichhoff published " Die Europjiischen Borkenkiifer," an 

 account written on less technical lines of the habits, economy, and characters 

 of the European species, and indispensable to the worker at forest entomology. 



In the handsome quarto before us Mr. Lflvendal, of the Copenhagen Museum, 

 has done on a more extensive scale for the bark-beetles of Denmark what 

 Eichhoff did for those of Europe ; and we can but regret that the utility of the 

 book is restricted by the comparatively little known language in which it is 

 entirely written. Mr. L0vendal has aimed at exhaustiveness of treatment both 

 in his descriptions of the insects, at least so far as their external characters are 

 concerned (for he does not follow Lindeman of Moscow far in that writer's 

 elaborate and not very productive researches on internal anatomy), and in his 

 accounts of their life-histories and economic relations. So far as we can judge, 

 he has fully succeeded ; and the labour devoted to the book may be estimated 

 by the fact that the list of works cited numbers close on two hundred, in which 

 we have not detected any important omission. 



The book, like that of Eichhoff, is furnished with full, perhaps even unduly 

 elaborate, tables of generic and specific characters, and for identification of the 

 species by means of their galleries and the kinds of tree attacked. In its plan 

 it closely follows its predecessor, so that those who know that useful work 

 will know what to expect here, though they will probably be surprised at the 

 scale on which it is earned out. 



Not its least valuable part is the full information given as to distribution 

 both within and without Denmark, the author having consulted all papers 

 throwing any light on this subject. We notice however, that, though he 

 records the existence of X. saxeseni, Batz., in North America, he, like most 

 European entomologists, is unaware that it was first described there, and should 

 bear the name of X. xylographus, Say. 



The number of species recorded from Denmark is fifty-one ; this is about 

 equal to the number in the British Isles, about a dozen species in each fauna 

 not being found in the other. It is likely that further research will increase 

 the number known from Denmark, as several species not recorded by L0vendal 

 may be expected to occur there. One species only is peculiar, Ips elongatus, 

 Liav. ; this has been treated by Beitter as synonymous with Ips austriacus, 

 WachtL, an identification which Ltfvendal does not accept. 



The text is illustrated with numerous pictures of burrows in bark and wood, 

 partly original, and partly copies. The galleries of several species are, we 

 believe, illustrated for the first time. 



But perhaps the most striking feature of the whole work is that of the five 

 plates, drawn and engraved by the author in a manner now rarely to be seen in 



