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result is two broad, flat, band-like bodies, terminating in front (fig. 
37) in three tracheæ the first of which has a lateral course, while 
the second is forward directed and sends branches to thé head; 
the third, inner branch is smaller and communicates with that 
from the other side. In the abdomen each of the main tracheæ 
sends a smaller branch to the alimentary canal and a larger, outer 
one which branches in a star-like manner; one of these branches 
Fig. 36 The bladders and adjacent parts of the tracheæ. 
is stronger than the others and runs into the preceding segment. 
In the 8th segment a strong trachea branches off, running into the 
anal”segment, sending out branches to the gills. 
The two large bladders in the thorax make one of the most 
peculiar structures in this larva. Perhaps they may best be compared 
with those of the Mochlonyx-larva, but while these are to be 
regarded as mere expansions of the main tracheæ, the bladders of 
the Mansonia-larvæ are freely placed laterally on long, angular 
branches inserted to the main tracheæ. It must be remembered, 
that air-bladders are extremely rare among insect larvæ; as far as 
