GENERAL MORPHOLOGY OF ANOPHELES 
AND CLASSIFICATION OF THE 
NEARCTIC SPECIES 
By W. V. KING and G. H. BRADLEY 
BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE, UNITED STATES DEPARTMENT OF AGRICULTURE, 
WASHINGTON, D. C. 
Morphologically the tribe Anophelini 
is an unusually homogeneous group of in¬ 
sects and for the most part is rather 
sharply differentiated from other tribes of 
mosquitoes, particularly in the larval stage. 
Adult anophelines are characterized 
principally by the long palpi in the female, 
club-shaped palpi in the male, a vestiture 
of hair, rather than scales, on the body, 
and a, rounded scutellum. The last also 
occurs, however, in Megarhinus. Absence 
of scales on the body is usually, or fre¬ 
quently, complete, but a number of species 
have some scaling toward the posterior end 
of the abdomen and a few have scale tufts 
on the abdominal segments. The palpi in 
both sexes are of about the same length as 
the proboscis. Nearly all anophelines have 
spotted wings, produced either by a clump¬ 
ing of dark scales, or more usually by al¬ 
ternating spots of black and white. Wing 
spotting, however, also occurs in other 
groups of mosquitoes. 
The mouthparts of anophelines are sim¬ 
ilar to those of other mosquitoes, but the 
number of maxillary teeth (consisting of 
fine serrations at the tip of the maxillae) 
has been given considerable attention in 
taxonomic work. Internally, the number 
of teeth and shape of the sclerotized plates 
in the pharynx serve to differentiate sub¬ 
genera and other species groups in the 
tribe. The principal characters are found 
in the toothed portion known as the phar¬ 
yngeal armature (Christophers 1933). 
Among the characters of the male geni¬ 
talia are the elongated, sclerotized meso- 
some, or phallosome, which, in the great 
majority of species, is surmounted by one 
or more pairs of small leaflets. The latter 
frequently vary in number and shape in 
different species. Below the mesosome and 
connecting the bases of the sidepieces is a 
membrane, which in most of the nearctic 
species is expanded on each side into a lobe 
having several spinelike hairs on the poste¬ 
rior margin. These lobes are called the 
claspettes, or basal membranous lobes, and 
the shape or arrangement of their spines is 
important in the classification of species. 
The modified hairs on the sidepieces also 
show differences of subgeneric value. 
In the larvae the absence of an elon¬ 
gated breathing tube distinguishes anophe¬ 
lines at once from other mosquitoes. The 
paired spiracles open into a large sclero¬ 
tized plate on the eighth and ninth ab¬ 
dominal segments. The larvae are also 
characterized by the presence of palmate 
float hairs on the dorsum of some or all of 
the abdominal segments and sometimes on 
the thorax. These structures, together with 
a peculiar pair of membranous, retractile 
organs on the anterior edge of the thorax 
(called the notched organs or retractile ap¬ 
pendages) serve to suspend the larva in its 
habitual position in the water just below 
the surface film. Below the spiracular ap¬ 
paratus, on each side, is a sclerotized plate 
vith a row of teeth, usually long and short 
ones more or less alternating, on the poste¬ 
rior margin. These plates have usually 
been referred to as the combs but probably 
correspond to the pecten in other Culicidae, 
the true comb scales being absent in anoph- 
eline larvae except in the first instar. 
The larval pilotaxy is notably consistent 
within the group in the number and dis¬ 
position of hairs but differs considerably 
from that of other kinds of mosquitoes. Of 
