84 [April. 



I am now able tr) state tliat the lavvae of this species have the same 

 remarkiil)l(' strueturc and hal)it.s as the North American T. lyerturhans 

 Wlk., /. e. they live among- the roots of water-grasses, from which they 

 ol)tain their sn)»ply of air hy the aid of a highly modified spiraeular 

 ajiiKiratus. 



The larva of T. pprfifrhans was well described and figured, and its 

 habits largely elucidated by ■). 11 Smith; all who may be interested 

 should consult his paper (Ent. News. xix. 1908, p. 22), and that by 

 (xrosslieek on the pupa in the same volume (p. 478) ; also the condensed 

 accoiuit in Howard, Dyar. and Knab's " Monograph of the Moscjuitoes of 

 Nortli America"" (vol. ili, part 1, p. 50S). The early stages of T. riclilardii 

 prove to be so nearly identical with those of T. perfurhans that by com- 

 paring specimens of the former with figures and descriptions of the latter 

 J have been unable to discover any points of difference.* Any detailed 

 description of T. ricliiardii would therefore be superfluous; nevertheless 

 several points have come under my notice with regard to our British 

 s])ecies which have ajiparently been overlooked by earlier writers and yet 

 seem worthy of being ])laced on record. 



7'. ;7'r7;/ry;v7//. abounds, in the winged state, round a pond near my 

 house at Letchworth, Herts, during June and July; males and females, 

 the former gi'eatly jireijonderating in numbers, hovering among bidrushes 

 and grasses round the water's edge. After a number of fruitless attempts, 

 I succeeded in obtaining about a dozen full-grown larvae, in June 191S, 

 by pulling up some of the water-gras-; (Glj/cerin Jluitaus) and shaking 

 out tlu; roots into a white dish. The Ti/pha roots, as well as roots of 

 other wate]--)>lants, \\ere examined in the same way. l)ut never jdelded 

 any larvae. Later, in November 1918, a few half-grown larvae were 

 f(Mnid among the roots of Gli/ceri(i,i so that it may be presumed that, 

 as in the case of T. itcrlnrhana, our British species spends the winter in 

 the larval state ; jiroliably there is only one generation in the year. 



A number of the larvae were kept under observation in small glass 

 bottles containing some Ghjceria roots, to which they could be observed 

 to attach themselves. They would remain for long periods attached in 

 (Mie s])ot, but nevertheless made frequent moves. Occasionally, especially 

 when distui-bed, they would rise to the surface of the water and hang 

 suspended there in the manner of an ordinary mosquito larva. Whether 

 they would ever do this in nature, and whethei- they could obtain 

 atmospheric air liy this means, may be doubted. 



* It would be quite reasonable to ivgavd these two forms as geographieal races rather thau as 

 true speeR-^, 3in;e the male genitalia, as well as the larvae and pupae, appear to be idi-ntieal in 

 3truct;niv. The two can, however, be sharply separated by the coloration of the hind legs. 



t One of these sijedmens lived without moulting until January 10th. 



