4 
A Monograph of Culicidae. 
are two labellae, which represent the labial palpi; these are in 
the form of two jointed spatulate valves. During the act of 
piercing the skin, all the mouth-parts but the lower lip (Fig. 5, Lp) 
are inserted ; the lower lip, or labium, bends and guides the 
other mouth-parts into the skin. The blood is drawn up the 
Section view (diagramatic) of part of a Mosquito mouth, &c. (when piercing 
the skin). 
Lp = lower lip ; MN = line of skin ; Ep = labrum-epipharynx ; Ep' = point of 
labrum-epipharynx ; C — clypeus ; A = bulb of epipharynx ; B = suctorial bulb ; 
C=poison gland ; Deduct; (lp=detached labrum (cut off) ; Ps=hypopharynx. 
(Maxillae and mandibles not shown, upper lip really united to epipharynx.)' 
upper lip, the tube being formed by the upper lip, and closed 
below by the hypopharynx. Attached to the maxillae are the 
two maxillary palpi (Fig. 7, III. p), which vary in each group, 
and are of specific but not always generic value; they may be 
short in the 9 only and long in the £ ( Culex ), or long in both 
sexes ( Anopheles ), or short in both sexes (Aedes) ; the joints vary 
from two to five, and are covered with scales, like the proboscis. 
There are also constrictions which are taken by Arribalzaga and 
others to represent joints (vide Fig. 11). 
(2.) The thorax is mainly composed of the middle division 
or mesothorax (when the thorax is spoken of the mesothorax is 
always inferred, unless otherwise stated). Although the major 
area is taken up by the mesothorax, both pro- and metathorax 
are represented. 
The prothorax (Fig. 7, I. pro) is present, more or less de¬ 
veloped, in all the Culicidae I have examined, as two so-called 
“prothoracic lobes” — two swellings between the head and 
mesothorax—in some these lobes are densely scaled and large, 
in others minute, ntide, or bristly. The mesothorax (mes) is 
large and convex, and forms the chief region of the mid-body ; 
behind it, or between it and the metathorax, is divided off* by 
