6 
are small in proportion to the length of the body. The whole aspect of the 
larva isin marked contrast to that of larvze to which projecting angles and hairs 
give a spiny look. (JMedanoconion, Culex, etc.) 
The head is smooth, and projecting hairs are inconspicuous. The clypeus 
forms a prominent boss, on which are situated, in some species, hairs very closely 
resembling the clypeal hairs of anopheles (PI. III, figs. 9, 10, 11), The 
antennze (PI. II, figs. 4 and 5), are very distinctive. They are very small and 
feeble and appear to have undergone degeneration. They are quite smooth and 
free from the numerous small thorn-like spines which cover the antenna of most 
other genera. The large hairs of the basal tuft are represented, as in anopheles, 
by a sinall branched hair or in some species by a single short bristle only. The 
median and terminal spines so conspicuous in Culex, Melanoconzon, etc., are 
represented only by several extremely small spike-like processes, As a rule, the 
terminal papilla (sense organ ?) is well developed and rather conspicuous. On 
the whole, the antenna of S¢egomyza larva approximates most nearly to that of 
anopheles, but in several points is still more rudimentary than in this sub-family 
(compare figs. 1 and 5, Pl. II). 
The mental plate of S. sugens is shown in PI. III, fig. 1. Those of S. fas- 
ciata and S. scutellarts are very similar. 
The siphon tube is very short and stout. The siphonic index is 2 or even 
slightly less. The spines on the siphon vary in number according to the species. 
They extend as a rule about two-thirds up the tube. There are mosquitoes, 
in which the larva has tubes closely resembling those of Stegomyza, which do 
not appear to belong to the genus; some of these have other features approxi- 
mating to those of Stegomyza and may be really related to the genus. 
The anal papillz are large and well developed. 
Specific variation.—Three species were examined: S. sugens, S. fasctata, 
and another species, probably S. scutellarzs. The following variations occurred :— 
Clypeal hatrs.—These hairs in S. fasczata remarkably resembled those of 
anopheles. The external hairs were long and simple. The two inner hairs were 
shorter and branched. In this species five or six branches were present. In 
S. sugens the inner hairs appeared to be absent and the clypeal hairs consisted 
only of two outer simple hairs. In larve which were probably those of S. 
scutellarzs the clypeal hairs were very striking. In this case each outer hair was 
double and the inner hairs were conspicuously branched (PI. II], figs. 9, 10, 11). 
The antenna.—The basal tuft in S. sugens was represented by a small hair 
divided into three or four branches. In S. fasciata a single small hair only was 
present (PI. II, fig. 5). 
The anal papille—Jn S. sugens and S. fasciata these were of moderate 
size, but in the larva of a third species (S. scutellarzs ?)they were extremely large, 
