44 The hish Naturalist. February, 



REVIEWS. 



THE LIFE OF AN INSECT. 



The Structure and Life-History of the Harlequin Fly 

 (Chironomus), byL. C. Miaxi,, f.r.s., and A. R. Hammond, f.vs. 

 Pp. viii. and 196; plate and 129 figures in text, Oxford: Clarendon 

 Press, 1900. 



It has been known for some time past that Prof. Miall was engaged 

 on a thorough study of Chironomus plumosus, one of our commonest and 

 most familiar insects, whether in its winged adult form as a midge or 

 in its larval form as a "blood-worm." The results of Prof. Miall's re- 

 searches, conducted with the able collaboration of Mr. A. R. Hammond, 

 and the gracefully acknowledged help of Miss D. Phillips and Mr. T. H. 

 Taylor, are now published in the well-printed and attractive volume 

 before us. 



After an introductory chapter sketching the life-history of Chironomus 

 in outline, briefly describing its near allies and discussing its relation- 

 ship to other Diptera, we find a very full and excellently illustrated 

 account of the larva. A somewhat brief description of the midge comes 

 next, as the intermediate pupal form depends so much on the structure 

 of the adult. Then follows a description of the growth of pupa and 

 midge within the larva, and an account of the full} 7 - formed pupa. In a 

 type like Chironomus, which has a comparatively highly-developed larva 

 and lowly-developed imago, the metamorphosis is simpler and much 

 more easily followed than in such intensely specialised Diptera as the 

 Blowfly and its allies, whose maggots are correspondingly degraded. 

 Consequently, the " Harlequin " fly serves as an excellent introduction 

 to the study of metamorphosis among the higher insects. The con- 

 cluding chapter deals with the growth of the embryo of Chironomus 

 within the egg up to the time of hatching. Thus the whole life-cycle 

 of the insect is worked through in detail, and although the order in 

 which the various stages are taken is not that in which they occur in 

 the life-history, few students can doubt that it is the best that could be 

 chosen from an educational standpoint. 



Like all Prof. Miall's work, this book is at once thorough, exact, 

 interesting, and stimulating. Details of structure are everywhere made 

 alive by the light which they are shown to shed on the function of the 

 insect, or on some fascinating question of morphology or affinity. The 

 organs of Chironomus are constantly compared with those of other 

 Diptera, so that the study of this single type becomes a means of 

 obtaining general knowledge of the group to which it belongs, and this 

 is surely the true end of the " type-system " in zoological teaching. ' In 

 the Preface we find a wish that we are glad to echo — that " members of 

 Naturalists' Clubs, and other non-academic biologists, should take up 

 the study of life-histories." Biologists, whether academic or otherwise, 

 could find no better guide to their study than this excellent book. 



G. H. C. 



