vil Lntroduction. 
Important specific larval characters have now been worked out 
onasmall scale. In the larvae of the Anophelina we find constant 
characters in the so-called “frontal hairs,” in the stellate palmate 
organs of the dorsum, and in the structure of the antennae. 
But with the exception of the Indian, a few African, and the 
European species, little is known of the larval characters. Drs. 
Christophers and Stephens have worked out the larval structures 
for most of the Indian species, and have shown the differences 
also in the eggs. Some species in the adult stage are almost 
inseparable, yet an examination of the scales will reveal the 
difference. The characters of the genitalia are not so marked ; 
many allied species have the claspers almost exactly alike. But 
in the Culicina there is great variation in the male sexual 
appendages. 
Since the last volumes were issued, we have found that some 
Anopheles have a wide distribution—e.g., adults of a species from 
Africa (Nyssorhynchus maculipalpis) are the same as some sent 
from India. 
In many respects the Culicidae are extremely variable ; this 
variation is chiefly in wing markings, and to some extent in the 
leg banding in certain species. The variation in wing-markings 
is said to be seasonal. The difference in position of the cross-veins 
in the same species has been demonstrated by observers in India 
(p. 5), and by the examination of the large amount of material 
recently received at the Museum, but this is certainly only in 
some species, others have the cross-veins fixed in one position. 
Drs. Christophers and Stephens, and Capts. Liston and 
James, I.M.S., have iaid particular stress on the palpal markings 
as being of specific importance. There is no doubt that the 
number and position of the pale bands on the palpi are extremely 
useful in hastily identifying a specimen, but these bands are only 
colour effects, and specific distinctions cannot be based on such ; 
moreover, specimens may frequently be met with showing varia- 
tion in this respect. These characters have all been pointed out 
in the following pages. 
A great deal of the new material in this volume has come from 
South America, Africa, and the West Indies, mainly collected 
by Dr. Lutz, Professor. Goeldi, Drs. Fajardo, Durham, Low, 
Grabham, Bancroft, Moffat, and St. George Gray. My thanks 
must be expressed to all these and other gentlemen for their 
kindly help, especially to Dr. Lutz, who has worked so assiduously 
at the life-history of the various species in Brazil. 
