REVIEWS 561 



whereas, at the end of 1912, at least fifteen valid species were recognised. In 

 teresting chapters on Interrelations of Insects and Insect Behaviour follow, the 

 latter considered under the head of tropisms, instinct, and intelligence, and are 

 succeeded by one on Distribution, which is treated both from geographical and 

 geological aspects. The concluding chapter (XIII) — Insects in Relation to Man 

 — gives among other things an account of the progress of economic entomology in 

 the various states of America. A useful bibliography, containing well over one 

 thousand references, and extending to 48 pages, completes the volume ; the text- 

 figures, many of which are original, are on the whole clear and well reproduced ; 

 the plates are similar to those of the first edition with the exception of the frontis- 

 piece, which has been omitted. 



This work is founded mainly on American types, and as far as possible only 

 the commonest species of insects are referred to, " in order that the reader may 

 easily use the text as a guide to personal observation." Although the book con- 

 sequently will appeal more particularly to American readers, it will be found to 

 contain much that will be serviceable to all who are interested in insect life in 

 other countries. 



H. F. C. 



The Genitalia of the British Noctuidae. By F. N. Pierce, F.E.S. [Pp. xii + 

 88, with 32 plates.] (Liverpool, 1909. Price 7s. 6d. net.) 



The Genitalia of the British Geometridse. By F. N. Pierce, F.E.S. [Pp. 

 xxix + 88, with 48 plates.] (Liverpool, 1914. Price ioj. net.) 

 (Both published by the Author, The Elms, Dingle, Liverpool.) 



The titles of these two volumes are perhaps a little misleading as they do not 

 treat of the whole of the genitalia of the species included in the two groups. 

 The first deals only with the male ancillary appendages, and the second includes 

 with these a description of the corresponding parts of the female. No account 

 is taken of the internal genitalia, the ovaries, testes, etc. 



The author was induced to examine the clasping organs in the hope that a 

 detailed study of their parts would solve, or at any rate throw light on, the 

 various riddles that confronted the systematists. This hope was in part realised, 

 for certain doubtful species of Miana can readily be distinguished by this 

 means, as also can several separate species formerly included together as 

 Hydraecia nictitans. It has, however, proved no panacea for all the ills the 

 systematist is heir to. The mode of preparation is given and a general account 

 of the clasping organs followed by a definition of the many terms necessary to 

 describe the various parts of these complex structures. The remainders of 

 the volumes are devoted to an account of the modifications of the parts in 

 practically every species of these two large groups of our British moths. Some 

 idea of the industry and patience of the author may be gathered from the fact 

 that the forty-eight plates of the second of the two volumes contain more than 

 1,500 figures, and that at least two preparations of each species have been made 

 and in a number of cases a great many more. The drawings were drawn to 

 scale by aid of a camera lucida (the exact magnification is not given, though it 

 would of course enhance the value of the plates). 



The full extent of a new field of investigation cannot easily be judged, but 

 this at any rate has already yielded some practical results and will probably 

 serve as a stimulus to other workers. No such comparative work has been 

 published previously in this, or indeed any other country, although the genitalia 

 of certain species have been included in general anatomical descriptions. The 



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