1918 
stand the great development of the swimming-brush in an animal, 
the whole life of which may almost be regarded as sedentary. The 
brush has changed its function; from an organ used for swim- 
ming motions by the other mosquito larvæ, it has, in the Man- 
sonia-larva, got quite another significance: viz. to force the sipho 
into the tissue. 
It is impossible to observe directly what happens after the outer 
tube of the sipho has fixed itself on the plant. We only see, 
that the slender part of the sipho has disappeared into the plant. 
The animal is fixed very firmly; if suddenly disturbed, it is almost 
incapable of leaving its hold, and if cut in two that part with the 
sipho will remain hanging down from the plant till it decays. After 
all, however, there can be no doubt with regard to the piercing 
process after the fixation of the outer tube. The series of hori- 
zontal cuts shows, that two powerful muscles run along with the 
chitin rod (figs. 27 and 331); the one end of each muscle is fast- 
ened to the broad, flattened end of the rod, the other is fixed to 
the chitin bow which separates the broad part from the slender; 
a little above that point two other muscles issue (fig. 33 u u1), 
running to the strongly chitinized posterior edge of the broad part 
of the sipho. A long ligament v fastens to the point where the 
tracheæ lose their tracheal structure; this ligament runs through 
the whole of the 8th segment; in the seventh segment it continues 
as a strong muscle (v1). The same facts are shown by the section 
(fig. 28). Ventrally, opposite to this ligament, another muscle (fig. 
33x) is placed; this is connected with the muscular system in the 
ninth segment by another, shorter muscle (y). There is no doubt 
but that contractions and dilatations of these long muscles, espec- 
ially those of the chitin rod, push the inner tube to and fro within 
the outer. 
The muscular system of the Mansonia tube may be thought 
to have arisen from the corresponding muscles of a common mos- 
quito larva through quite small modifications (fig. 33 and 34). 
Raschke states, that the sipho of the Culicidæ is furnished 
with five pairs of muscles: two ventral pairs, two dorsal, and oné 
attached to the chitin rod; the ventral and the dorsal pairs aré 
fastened to the two pairs of flaps in the closing-apparatus; they 
traverse the long sipho through the whole of its length and are con- 
