14 
thorax of the larva of Zoxorhynchztes and the absence (?) of the spines of the 
siphon tube in this species. Siphonic index is 2°5 (Pl. III, figs. 12 and 19). 
C. concolor.—in general appearance the larva exactly resembles that of 
Muctdus. The antennz and siphon-tube are, however, different. The antennz 
are small and very unlike those of any other larva (Pl. HI, fig. 11). The siphon 
tube is highly characteristic and possesses a structure not represented in any 
other larva yet described (with the exception of the related species C. ¢igrtpes). 
This is a large fan of hairs springing from the median posterior line of the 
siphon tube (Pl. III, figs. 17 and18). The shape also of the siphon tube in 
C. concolor and C. tigrzpes is quite unlike that of any other larva. The nymph 
has respiratory trumpets differing from those of Cwlex. They project ina 
characteristic way from the body of the nymph (PI. I, figs. 14 and 23). 
Psorophora.—From Howard's description of P. cz/zata it is evident that the 
larva is morphologically adapted for cannibal habits and resembles closely that 
of Mucidus. 
Lutzta.—The characters of this larva, so far as 1 am aware, have not been 
described. 
III. 
From the above descriptions it will be seen that the most important varia- 
tions occur on the following structures :— 
. The respiratory trumpet of the nymph. 
. The antenna of the larva. 
. The siphon tube of the larva. 
. The mental plate of the larva. 
. The feeding brushes of the larva. 
. The anal papille of the larva. 
. The form of the ovum. 
. The arrangement of ova in rafts or otherwise. 
g. The form of the raft. 
aA AuNbwWDND H 
The shape of the nymph trumpets appears to vary little in species of the 
same genus, but to be of great importance in the distinction of different genera. 
By means of the variations on the trumpets the following groups may be 
obtained. . 
1. Trumpets expanded to form a flap (Pl. I, figs. 1 and 2). . Anophelina. 
2. Trumpets expanded broadly triangular in shape (PI. I, figs. 3, 4, f Stegomyta. 
and 5) Desvoidea. 
3. Trumpets narrow with oblique opening (PI. I, figs. 7 and 9) - . Culex. 
4. Trumpets extremely long and narrow ; opening not so oblique 1/elanoconton. 
as above (PI. I, figs. 8 and 10). 
5. Trumpets project forwards (Pl. I, figs. 11 and 13). : ; ee 
