104 
Anopheles Maeulipennis 
The muscles of the brushes consist of two pairs, an external and an 
internal (Figs. 1 and 2). Both pairs arise from the dorsal wall of the 
head-capsule, and their points of origin coincide with certain sym¬ 
metrical patches of pigment situated on the surface of the head. Each 
pair passes forwards to be inserted into the base of the brush of its 
side. The external muscles (&'. m'.) take their origin between and in 
front of the eyes, and are separated from one another by an interval 
equal to about half the diameter of the head at its widest part. They 
converge somewhat as they pass forwards, and each muscle is attached 
to a chitinous apodeme of the epipharynx. The internal muscles (b.m.) 
arise almost in contact with one another in the middle line of the head 
just behind the eyes. For the greater part of their course they run 
almost parallel with one another, and are likewise inserted into a pair 
of apodemes at the bases of the brushes, slightly above and internal to 
those of the external muscles. 
With regard to the working of these muscles, so far as could be 
ascertained, they appeared to contract simultaneously with the result 
that the brushes are depressed so that they become directed backwards 
and inwards and lie within the space enclosed by the mouth-parts, and 
their setae come in contact with the surface of the epipharynx. When 
the muscles are relaxed the brushes regain their normal attitude in 
virtue of the elasticity of the chitinous framework at their bases upon 
which the strain is exerted. 
The rapid backward and forward motion of the brushes can be 
readily observed, and though as a rule they work simultaneously, at 
times one brush may work independently of its fellow. 
A third pair of muscles, the epipharyngeal muscles 1 ( ep.m. in Figs. 
1 and 2), arise from the middle line on the roof of the head-capsule and 
just behind the points of origin of the external muscles of the brushes. 
They pass forwards very nearly parallel to each other and are inserted 
close together into the membrane of the epipharynx behind the points 
of insertion of the muscles of the brushes. They appear to function 
principally as elevator muscles to the roof of the mouth. 
At the base of each antenna, along its inner aspect, an antennal 
muscle (atm. in Fig. 1) is inserted. It takes its origin from a strongly 
chitinised apodeme (the tentorium) arising from the floor of the head. 
The muscle passes obliquely upwards and outwards in its course to the 
antenna. 
1 These muscles have already been referred to in the account of the pharynx ( Journ. 
of Hyg. 1907, p. 299). 
