76 



the Q.M.O. in 1879 {Journ. Q.M.C. Ser. 1, Vol. v, pp. 250-5). 

 That address contains, beyond question, some of the sanest things 

 that have ever been said about " Microscopy," and it well deserves 

 to be read again and again. D. J. S. 



The Structuee and Life-IIistory of the Harlequin Fly 

 (Chironomus). By L. C. Miall, F.R.S., and A. E,. 

 Hammond, F.L.S. 9 x 5|in., viii -f 196 pages, 1 Plate, 

 129 figures in the text. Oxford, 1900 : Clarendon Press. 

 Price 75. 6<i. 



It was an exceedingly good sign of the excellence and suggestive- 

 ness of Professor Miall's book on the " Natural History of Aquatic 

 Insects," published in 1895, that nil those who had the good fortune 

 to read it came to the conclusion that it would be a capital thing 

 if a greatly extended work on the same subject could be written. 

 In a certain sense the book now under review is the response tO' 

 that very real, if somewhat inarticulate, appeal for more. 



Taking a single one of the insects dealt with in the earlier work 

 {Chironomus), Professor Miall and Mr. Hammond have en- 

 deavoured to present us with a pretty full account of every 

 phase of its life-history. Under the head of the " Larva of 

 Chironomus," an elaborate description is given of the " blood- 

 worm " so well known to all collectors of pond-life. The general 

 structure, appendages, nervous, digestive and circulatory systems^^ 

 organs of respiration, etc., are gone into in detail. Especially 

 interesting are the remarks on wandering cells, on the peculiar 

 cells known as oenocytes, and on the haemoglobin in the blood. 

 The fly is dealt with in the same thorough-going way, special 

 attention being paid in this case to the supposed auditory organs 

 in the antennae, and to the sexual organs. The development of 

 the pupa and the fly within the larva forms a very interesting 

 chapter. It is pointed out that although Chironomus is less com- 

 plex in its final stage than the blow-fly and other Muscidae, in its 

 larval stage it is more complex. The transformation therefore 

 from the larva to the perfect fly is more intelligible, the difference 

 between these forms not being so great. On the whole Chiro^wmus: 

 seems to be the best fitted of the well-known Dipterous types, for 

 an elementary study of imaginal development. The final chapter 

 of the book gives a succinct account of the embryonic development. 



