42 W. WEe^CHE — THE LARVAL AND 



number, consisting of compound hairs of about six plumose hairs or branches 

 (PI. I, fig. 2). 



Thorax fairly large and differentiated, with the segments obvious ; with 

 the usual series o£ single, double, and triple plumose hairs along its dorsal 

 anterior edge, which reach forward over the head ; the anterior segment 

 bears lateral plumes, and on each of its upper sides one of those miuute 

 stellate hairs, w^hich seem to represent an early stage of the " palmate hairs " 

 in Anopheles (PI. I, fig. 3). The middle and posterior segments bear souie 

 long dorsal single plumose hairs and two pairs of long lateral plumes. 



The first three and the eighth segments of the abdomen are shorter than 

 the others. The first two carry lateral plumes, the upper consisting of two 

 and the lower of four and three plumose hairs. The other segments carry 

 shorter single hairs of various lengths_, the longer subplumose and the short 

 simple. The third to the seventh segments carry minute stellate hairs on 

 the dorsal side. The sub-siphonal plumes are moderate in size, as are also 

 thesiphonal; the hairs of both are very plumose ; the plume at the base 

 of the anal segment consists of 3-4 subplumose hairs. The combs (on the 

 eighth segment) are difficult to make out, but appear, anteriorly, as a number 

 of minute scales in a long and regular row^ followed by one or two irregular 

 rows of bigger scales ; they show best if the transparent membrane between 

 the eighth and anal segments can be brought into A'iew ; the appearance of the 

 scales is peculiar and I think there are at least 40, but T found it impossible 

 to get the whole process into one focus of even low-power objectives, without 

 dissecting the larva. 



The siphon is thick and suboval ; it is mostly without any colour or 

 marks, and the length is not quite four times that of the base (PI. I, fig. 4). 

 The spines do not begin at the base, but after an interval which is ^ of 

 the length of the siphon ; they are fairly long, but are only three or four 

 in number. They are immediately followed by a pair of long hairs, just 

 before the middle, and midway between these and the end is another pair 

 placed transversely, and following these a short triple hair (all these spines, 

 hairs and triple hairs are symmetrically paired). 



The anal segment, at its greatest chitinous length, is less than I of that 

 of the siphon. The papillae, though hyaline, bear some markings ; they are 

 unequal and fairly long ; two are double the length of the segment, and two 

 (the dorsal) about a third longer — all fairly stout and with moderately pointed 

 ends. At the dorsal edge of the segment are four long hairs which are 

 longer than the longer papillae. There appear to be no long hairs on the 

 ventral edge, but there is a compound plume (ventral beard) which springs 

 from six bases_, and is longest at its posterior portion, where it about equals 

 in length the shorter papilla?. It will be noticed that all the hairs on the 

 anal segment are simple, and this is the prevailing condition ; they are more 

 liable to injury and denudation than those on any other part. 



