300 



J. W. SCOTT MACFIE. 



The two pairs of ventral hooks (fig. 3) increase in size and in the degree to which 

 they are chitinised as the larva grows. In the first phase they are hardly chitinised 

 at all, and are represented merely by four minute sharp-pointed structures. With 

 each moult the hooks enlarge and strengthen, until in the last phase they assume the 

 formidable appearance so familiar in these larvae. 



Fig. 3. One of the ventral thoracic hooks in each of the four stages of the larva of 



Stegomyia fasciata. 



The arrangement of the hairs clearly indicates the three segments of the thorax at 

 each stage of the development. The hairs increase in size, strength, and complexity 

 as the larva grows, and their subplumose structure, which in the first phase is all but 

 invisible, becomes more marked. The anterior dorsal plumes appear to be absent 

 throughout the larval period. 



Fig. 4. Larva of Stegomyia fasciata ; the second abdominal segment in the 



four stages. 



Abdomen. The hairs on the abdomen are not very numerous and are mostly small 

 and simple, but a few little triple hairs (stellate hairs) are also present, and some long 

 conspicuous hairs (fig. 4). In the first phase the long hairs are double, and are with 



