THE LARVAE OF MALAYAN ANOPHELES. 165 



The frontal hairs are six in number as usual, but only the two external ones are 

 branched. The four internal hairs are very delicate. The antennae each possess a 

 branched hair, as in barbirostris and sinensis, and the Indian species lindesayi, but 

 it is situated on the external side of the antenna. 



Thorax : There are no palmate hairs on the thorax. There is a deposit of black 

 pigment in the form of a Maltese Cross, the posterior hmb of which is bilobed. 



Abdomen : In this region of the body the palmate hairs are slightly developed on 

 the 2nd segment, well developed from the 3rd to 7th segment ; they are large and 

 pigmented. Each leaflet is long and rather slender, terminating in a long filament 

 without any very jagged shoulder. There is a dense black spot on the dorsum of the 

 4th segment." 



A hair situated on the dorsum of the head near the base of the antenna (*' basal 

 hair " of James and Liston) is of unusual form in this species. In most Anophehnes 

 this hair is stout and feathered— in asiaticus it is long, slender and bifurcate 

 terminally. The occipital hairs are short, slender and simple. The average length 

 of the leaflet in the stellate tufts of the mid-abdominal segments is 0'08 mm. The 

 average relation of length of filament to total length of leaflet is as 1 to 2*5. 



I have found in the water of cut bamboos an immature AnopheHne larv^a which is 

 perhaps one of the early stages of asiaticus. It differs from the mature form described 

 by Strickland in the form of certain of the head hairs. In my specimen the inner 

 anterior clypeal hair has four to five lateral branches, the " basal hair " consists of a 

 simple stem with a swollen extremity carrying a tuft of hairs (as in the larva of the 

 Indian species culiciformis). The posterior clypeal hairs are minute, only about 

 half the length of the outer anterior clypeal hairs. The outer pair of frontal hairs 

 are branched as in asiaticus, the median pair short and simple, the inner pair long 

 and bifurcate. A branched hair is borne on the antenna and stellate tufts are present 

 on abdominal segments iii. to vii. only. There is a deposit of pigment of irregular 

 form in the cuticle of the dorsum of the thorax. 



4. Anopheles barbirostris, Van der Wulp, (fig. 7). 



Average length at maturity 5*5 mm. The larva of this species is usually dark- 

 coloured, with light bands across the front of the thorax and abdominal segments 

 iii. V. and viii. 



Hi:/ o : Anterior clypeal hairs. Inner hairs close together, long and simple ; outer 

 hai^r, sliorter, thickly branched. Posterior clypeal hairs short, branched, with three 

 or four divisions. Occipital hairs short, both branched, with seven or eight divisions. 

 Antenna. On the inner surface about the middle the shaft carries a long branched 

 hair. 



Thorax : Sub-median anterior thoracic hairs (fig. 3) as follows, from the mid 

 line :• — (1) a short hair branched near the base, with six divisions ; (2) a long stout 

 plumose hair ; and (3) a long simple hair externally. On the posterior quadrant a 

 fully developed stellate tuft composed of twelve to fifteen long narrow leaflets \\ithout 

 filaments (fig. 3, b, B). 



Abdomen : Segment i. carries a fully developed stellate tuft composed of eight to 

 ten long narrow leaflets without filaments. Segments ii. -vii. carry fully developed 

 stellate tufts composed of about twenty long broad leaflets. The average length 

 (C177) F 



