Noland—Anatomy of Troctes Divinatorius Muell. 
199 
covered fleshy lobes which form the ligula (fig. 6, v.L). The men- 
tum is borne on a very short submentum (fig. 6, s.m.). So closely 
attached to the dorsal side of the labium as really to form a part 
of it, though designated by Burgess the tongue, is a thin plate 
(fig. 6, d.p.) which extends undivided as far forward as the tips 
of the lobes of the ligula, and in it and the labium itself the labial, 
or ^‘lingual’’ glands (fig. 6, l.g.) are imbedded. The glandular 
nature of these structures has been doubted, but their appearance 
when examined in section is distinctly that of glandular cells. 
Each cell has a nucleus large in proportion to the size of the cell 
and containing a distinct nucleolus. It is difficult to explain the 
fact that the outer walls of these glands are of heavy chitin, but 
they are obviously neither reservoirs, nor merely chitinous sup¬ 
porting structures as has been supposed. Unlike the glands of 
Psocus, those of Troctes are not supported by any sort of cap or 
peduncle. They have no support except their position, imbedded 
in the labial tissue. From them chitinous ducts extend a short dis¬ 
tance forward and then turn backward to unite with one-another 
between the two glands. The common duct so formed leads back 
between rows of gustatory cones (fig. 6, t.c.) or pegs, more rounded 
than hairs, into the oesophageal sclerite between its two anterior 
horns. This sclerite (figs. 4 and 6, o.s.) is a chitinous ‘^bonnet- 
shaped’’ structure which extends two anterior arms, or horns, for¬ 
ward for support in the labium, and one backward onto a flat chit¬ 
inous plate which is held on each side by two smaller rods extend¬ 
ing out toward the sides of the head. The large masses of muscles 
of the clypeus, already mentioned, which are attached to the dorsal 
wall of the oesophageal sclerite, are said by Burgess (5) to function 
in closing the oesophagus, but it seems improbable that their con¬ 
traction, situated as they are, could produce such an action. 
The Digestive System 
The mouth opens through the oesophageal sclerite into the long 
slender oesophagus, or fore-intestine. This extends through the 
thorax into the first or second abdominal segment where it joins 
the mid-intestine. The anterior portion of the oesophagus is nar¬ 
row and has its origin at the oesophageal sclerite, turning in a 
slightly dorsal direction before passing posteriorly. In the thorax 
it enlarges into a crop-like structure (fig. 7, cr.) which has thin 
walls histologically the same as those of the oesophagus. At the 
