THE CAUDAL TUFTS OF MALAYAN ANOFIIELINE LARVAE. 



93 



that the longest is about a quarter as much again the length cf the shortest. All are 

 of about the same calibre, which is practically uniform from end to end, and each of 

 the five is recurved at its extremity, so as to form a rounded hook. The sixth bristle 

 differs from the other five in being considerably shorter and in bearing seven lateral 

 filaments, all of similar calibre but of different lengths, the two longest showing hooks. 

 Not one of the bristles is perfectly straight, each showing a curve first upwards and 

 then gradually in the reverse direction, more sharply towards the extremity. The 

 ventral brushes consist of separate tufts of feathered filaments, arranged fanwise, 



Fig. 1. Terminal segments of larva of Anopheles maculatns, Theo. 



tapering gradually towards the extremity, which is pointed. They are apparently of 

 less brittle material than the dorsal bristles ; for whereas these often have the hooks 

 broken off, or may be broken short when the larva has been much shaken about, the 

 central filaments seem not to suffer such damage. 



The hooked bristles are present throughout larval life. In the newly hatched larva 

 there are two only on each side, and the number increases at each moult. The same 

 structures are to be seen without any modification of form in the larvae of the following 

 Anophelines : — A. kanvari, A. hyrcanus {sinensis), A. kochi, A. hidlcwi, Thee, and 

 A. suhpidus (rossi) and its var. A. vagus {indefinittts). In A. fuliginosus, Giles, A. 

 barbirosfris, A. umbrosus, Theo., A. tessellatus, Theo., and A. aconiUis, there are, as a 



^^ 



Fig. 2. Terminal segments of larva of Anopheles asiaticiis, Theo. 



rule, five main hooked bristles only; in A. alhotaeniatus, Theo., var. montanus, 

 Stant. & Hack., there are, as a rule, five, and the upper of the dorsal tufts shows 

 considerable reduction in size. In the case of A. aitkeni, James, and A. asiaticiis, 

 Theo., there are marked differences ; in aitkeni there are six main hooked bristles, one 

 of which shows a branch almost as long as itself and also hooked, so makmg an 

 additional main limb ; moreover, the upper of the two dorsal tufts shows many more 

 fine hooks at the extremities of the constituent hairs than in other species, doubtless 

 in adaptation to its mode of life, the species breeding in mountain streams ; m 

 asiaticHS (fig. 2) there are only two, or sometimes three, hooked bristles, which are 



