STRUCTURE AND BIOLOGY OF SCHIZONEURA LANIGERA. 675 
rod passes at right angles into the head towards the proximal 
end of each mandibnlar seta. A narrower and more elongate 
rod passes beneath each maxillary seta. These structures I 
have called the mandibular {m. r.) and maxillary [mx. r.) 
chitinous rods. 
The mandibular rods are stouter than the maxillary rods, 
and expanding at the base, fuse with the continuation of the 
antero-ventral rods aud the antero-lateral walls of the clypeus. 
The maxillary rods are attached at the base of the mandi- 
bular rods, from whence they curve ventrally, pass beneath 
the proximal portion of the maxillary setse aud fuse with them. 
Two thin rods of chitin [v. r.) (“ Ohitinfortsatzestabchen ” 
of Mordwilko), to which are attached a few muscles from the 
salivary pump, arise from the posterior end of the buccal 
cavity and extend beneath the phai’ynx towards the trans- 
verse bar where they fuse. 
The Buccal Appendages. — The buccal appendages con- 
sist of the labrum, mandibles, first pair of maxillae, and the 
proboscis or labium. 
The labrum and labium have been described above under 
the head appendages. 
The mandibular setae {m. r.) are situated in the head below 
the pharynx, being supported by the two mandibular chitinous 
rods described above. At their proximal ends they are 
greatly enlarged, but as they pass towards the buccal cavity 
they become considerably attenuated and approximate closelv 
to one another in the median line. They are finely pointed 
at their distal ends, and each is composed of stout chitin with 
an extremely fine cavity running throughout its length. After 
leaving the head they pass through the buccal cavity aud 
extend along the proboscis groove. The flexible chitin of the 
buccal cavity is attached to the walls of the mandibles, which 
thus permits of free movement of these structures (fig. 33). 
When they are retracted into the head, the sheath is drawn 
inwards after the manner of an inverted finger of a glove. 
The maxillary setae {mx. r.) ai’e situated immediately 
posterior to the mandibles, which they resemble in structure. 
