16 A Monograph of Culicidae. 
value when we are dealing with two such closely allied insects 
as urgyrotarsis, of Desvoidy, and my so-called sub-species albipes. 
If there were proved to be a difference, say, in the frontal larval 
hairs, then I would look upon my sub-species as a distinct 
species, but, until that is proved, I cannot agree with Colonel 
Giles and others in raising it to a speties because it has a black 
band on its hind tarsi, whereas argyrotarsis has not. It is 
most important to trace out these larval characters as long as 
we are certain that we are dealing with the larvae of a known 
imago; but if we give an account of the larva of something we 
think it may turn into, then endless confusion will ensue. 
(Take, for instance, Giles’s figure of the frontal hairs of M. 
Rossit.) 
In Culicina the difference of the larvae is still greater; the 
notable differences will be seen to be in the size and shape of the 
respiratory siphon and in the anal flaps. The genus Desvoidea 
certainly comes very dangerously near Stegomyia on adult 
characters, save the palpi, and yet we find a great difference 
between the larvae of the two genera (vide fig. 16, Vol. L., 
and Plate XVII., III.). Here, again, the separation or union 
of pseudo species, or species respectively, may be helped by 
larval characters. Culex jfatigans and its various sub-species 
and varieties I feared might prove to be different species on 
larval characters, but I have so far.been unable to find any 
difference in the larvae from different parts of the world, and 
thus I feel more sure that the great number of differently 
coloured, different sized Culex in which there is such enormous 
variation in the relative positions and lengths of the cross-veins, 
fork-cells, and their stems, are really all one elastic species. 
In the eggs (vide fig. 2) of Anopheles we also find con- 
siderable difference in the different species. Most of the Indian 
species have been figured by Drs. Christophers and Stephens. 
In the Culicina there does not seem to be such a great difference 
in species, but, as previously pointed out (Vol. I., p. 19), there 
are considerable differences in the eggs of different genera (i.e., 
Mansonia and Stegomyia). 
