NA TURE 



THURSDAY, MAY 



THE ANOPHELES MOSQUITOES OF IXDIA. 



A Mouogrtipli oj tlic Aiiopliclcs Mosquitoes of India. 



By S. P. James and Dr. W. G. Liston. Pp. 132 



and plates. (Calcutta and London : Thacker and 



Co.) Price 24s. net. 



THERE is one feature in which this book far 

 surpasses any other devoted to mosquitoes, viz. 

 the coloured plates. The authors and their artist. 

 Dr. Turkhud, are to be congratulated on the excel- 

 lence of these pictures. It will be now possible to 

 compare an Indian Anapiieline with a plate, and with 

 practical certainty to be sure of its identity. The 

 same could not be said of any representations of 

 mosquitoes hitherto produced. These plates are 

 beautifully executed, and depict faithfully the bands 

 on the palpi, the spots on the wings, and the leg 

 markings. It is a pity that some few Anophelines 

 are not represented, but of these we have, of course, 

 the systematic description. 



The book is divided into two parts : (i) general, 

 (2) systematic. The first chapter gives a general 

 account of mosquitoes, egg, larva, nymph, and ex- 

 ternal anatomy of the imago. The description is clear 

 and adequate for medical men, for whom the book is 

 primarily written. We think perhaps a short account 

 of the internal anatomy might have been added, as a 

 knowledge of this is so important. The chapter ends 

 with a short account of Theobald's classification of 

 mosquitoes, which the authors are unable to accept. 

 Instead of dividing the subfamily Anophelina into 

 twelve genera as Theobald has done, they place them 

 all (at least the Indian ones) in the old genus 

 Anopheles. We cannot help thinking that this, in 

 spite of some of the difficulties of Mr. Theobald's 

 classification which they point out, is a retrograde 

 step. The authors deal with a total of twenty-four 

 Indian species; the total number of ."Anophelines, how- 

 ever, now amounts to nearly a hundred, and, to say the 

 least, it would be very inconvenient, if not impossible, 

 to deal with these if we placed them all in a single 

 genus. In some of these, e.g. Lophoscelomyia, 

 Christya, the difference in scale structure is so marked 

 from, for example, a typical Myzomyia that we prefer 

 to follow Mr. Theobald and put them in separate 

 genera. Again, we do not know whether the authors 

 would propose, ignoring scale structure, to arrange 

 the rest of the Culicidae in a single genus, Culex, and 

 take no notice of the obvious differences in scale 

 structure, e.g. between Mucidus and Culex, or be- 

 tween Stegomyia and Culex. We think, to be logical, 

 they should do so, and try to classify them by palpal 

 bands and leg markings ; but this would be well-nigh 

 impossible. We think the authors would have made 

 their position more secure if they had been content 

 with placing in the same genus only those in which 

 they failed to recognise the differences in scale struc- 

 ture defined by Mr. Theobald. It may be granted 

 that doubts sometimes arise, but we cannot regard 

 NO. 1856, VOL. 72] 



this as an excuse for merging into a single genus 

 those in which the differences are well marked and 

 easily appreciable. 



The second chapter contains a synoptic table of the 

 Indian species of Anophelines, based upon the author's 

 classification accoi'ding to palpal bandings, wing 

 spots, and leg markings ; the chapter concludes with 

 a description of the method of identifying Anopheline 

 larvae. The essential points are very clearlv set forth, 

 and there follows a classification— a modification of 

 that originally constructed by Stephens and Christo- 

 phers. One point noticeable as showing that even 

 all the Indian Anopheline larvae are as yet unknown 

 is that the table only contains eighteen species, 

 whereas the table of imagines contains twenty-four. 

 This table should be of great assistance in helping 

 actual workers in identifying their catch of larvae 

 from any source. 



The third chapter is devoted to the habits of 

 Anophelines. These most interesting questions are, 

 as the authors admit, only beginning to be studied, 

 and now that a book of this kind enables observers 

 to identify their mosquitoes, we may expect much 

 light on these questions — questions of vital import- 

 ance, but to which many pay no attention. One of 

 the most interesting problems is the distance of flight 

 of Anophelines. Christophers and myself found in 

 Africa instances which proved conclusivelv that nor- 

 mally the flight of Anophelines was quite a restricted 

 one, to be counted in yards and not in miles, as was 

 not uncommonly stated. A striking example of this 

 we found in the central portion of Freetown, Sierra 

 Leone. .-Mthough we lived there for several months 

 during the dry and rainy seasons, we never discovered 

 Anophelines in our rooms, yet a quarter of a mile 

 away they existed in myriads in the native huts ; and 

 many other similar instances were observed by us. 

 Yet in Mian Mir observations are quoted to show 

 that P. fuUginosus will on occasions fly two and a 

 quarter miles, and M. rossii three-quarters of a mile. 

 But, of course, the conditions at Mian Mir are very 

 different — in one case an open plain, in the other a 

 crowded town. Closely bound up with this problem 

 is the question of dispersal of Anophelines. Two of 

 the most important means are (i) by flight, (2) "by 

 a gradual spreading, by short stages, from areas in 

 which they are abundant." This latter method is, it 

 seems to us, one of the most important and over- 

 looked by those who have no intimate knowledge of 

 mosquito habits, but who readily draw up schemes 

 for their wholesale destruction. We agree with the 

 authors when they state, " observers who consider 

 that Anopheles can be materially reduced in numbers 

 by the obliteration of all breeding places in the imme- 

 diate vicinity of dwellings, rely chiefly upon the sup- 

 positions that the range of flight of these insects is 

 very limited and that they do not disperse any 

 considerable distance from their breeding grounds. 

 It would appear from the observations just recorded 

 that such suppositions are incorrect, and if this is so, 

 the task of materially reducing the number of 

 .\nopheles in any place will undoubtedly be one of 

 great magnitude." 



