REVIEWS ^77 



of Genghiz-Khan, yet such was the means of entering this land adopted by 

 the expedition. The modern invention was used in a very striking way to 

 test the speed of some of the animals on the hard, level plains. It was found, 

 for example, that the wolf, even in its opening burst of speed, did not travel 

 faster than thirty-five miles an hour as registered by the speedometer. Oa 

 the other hand, the antelope [Gazella guUurosa), can keep up for some time a 

 speed of between thirty-five and forty miles an hour, and then, when frightened, 

 by being fired at, can increase this to between fifty-five to sixty miles, although 

 this is only maintained for a mile or so. 



The book also contains information on a number of other mammals and 

 birds, particularly on the Argali and the Wapiti. It is also useful for the 

 account it gives of the ordinary life of the peoples of this little-known land, 

 and forms most enjoyable reading from cover to cover. C. H. O'D. 



Typical Flies. A Photographic Atlas. By E. K. Pearce. Second Series 

 [Pp. xiv + 38.] (Cambridge: at the University Press, 1921, Price 

 155. net.) 

 This atlas is supplementary to the one published in 19 15, and consists of a 

 series of 125 half-tone illustrations of British Diptera, either in their adult or 

 immature stages. Many of the figures are evidently reproduced from re- 

 markably clear photographs. The latter must have often been executed 

 under difficulty, since it is almost impossible, with the magnifications used, to 

 get all parts of an insect in sharp focus simultaneously. The book should 

 prove a help to the beginner to sort out some of the members of this difi&cult 

 order into their respective families. It needs, however, to be used in conjunc- 

 tion with a textbook (that of Williston being almost the only one in the English 

 language), or the student will soon find himself relying solely upon appearances 

 and will remain ignorant of the characters upon which the families are based. 

 The work of Williston should at least have been quoted in the list of books 

 given in the preface. 



Mention is made of species to be added later, which suggests a third series 

 of Typical Flies. In the event of an additional part being produced it is to 

 be hoped that a reduction in price will be possible. The sum of twenty shil- 

 lings, for the two parts already issued, is a rather high price to pay for a series 

 of photographs of insects without any, except very meagre, letterpress relating 

 to the order and famihes to which they belong. A. D. Imms. 



Insect Transformation. By Prof. G. H. Carpenter, D.Sc. [Pp. xi -f 282, 



with 4 plates.] (London : Methuen & Co., 1921). 12s. 6d. net. 

 Prof. Carpenter's book describes in clear language the varying degrees 

 of change among insects during their growth from the time they issue from 

 the eggs until they appear as perfectly formed adults. It deals with an 

 abundance of material of interest not only to the entomologist, but to any intel- 

 ligent person upon whose thoughts natural phenomena have some hold. In 

 order that these changes may be fully appreciated, an introductory account 

 of the form and structure of a typical insect is desirable, since all development 

 tends towards this adult state. With this object in view. Prof. Carpenter 

 devotes about twenty-four pages to the elements of insect morphology. In the 

 succeeding chapter he explains first the simple and afterwards the more 

 complex cases of insect metamorphosis. In a later chapter he discusses those 

 insects that are wingless : some primitively so, and others secondarily so, 

 the latter often tlirough adopting a parasitic mode of life. The primitively 

 wingless forms are of importance in that they provide an insight into how 

 metamorphosis first arose as a definite, although inconspicuous, process of 

 change in the course of growth. Another chapter is devoted to the bearing 

 of metamorphosis upon classification, and the importance which is ascribed 

 to it in our present-day grouping of the different orders of insects. The sur- 



44 



