28 Journal of the Asiatic Society of Bengal. [N.S., XIX, 
the remaining posterior segments. The tergum of segment 1X 
is narrow and almost encloses that of X (Fig. La), whilst 
its sternum (A9 Figs. Llb, llc) consists of two flat plates, 
the inner margins of which are thickened and hardened From 
the tergum and sternum of IX, hang down two pairs of thin 
curved processes. Segment X ‘surrounds the anus. Dorsally 
and laterally it is enclosed by IX. An ovipositor is absent, 
since bie animal lays its eggs in soft places between crevices of 
the s 
oi es 
Length of abdomen in male 7 mm. 
Breadth a 4 mm. 
Length of abdomen in female 8:25 mm. 
Breadth .... variable in female. . 4:5—-—5°5 mm. 
ANATOMY—INTERNAL. 
Digestive system—The mouth leads into the suctorial 
pharynx which is of special importance in the Rhynchota. 
The pharynx is a long chitinous tube with a narrow lumen. 
Its ventral wall is strongly chitinized, whilst the dorsal, termed 
operculum, is flexible and elastic. There is a double row of 
pharyngeai muscles arising from the under surface of the dorsal 
wall of the head and inserted on the operculum, where they 
split up into a number of strands (Ph.M. Figs. 8b-8f). When 
these muscles contract, the operculum is pulled upwards so as to 
widen the pharynx, and the plant-juice is sucked up through 
the rostrum. 
The minute anatomy of the pharynx (Fig. 8) varies in the 
different parts of the head capsule. In the epicranial region, 
where it is surrounded on all sides by the cerebral nervous 
ganglia (Fig. 8a), the pharynx is thin-walled and almost 
circular in transverse section. On emerging from this mass. 
the pharynx enters the clypeal region where its ventral wall 
becomes comparatively thicker than the dorsal (Fig. 8c) ; 
beyond this region the difference in thickness increases, and the 
ventral wall is drawn down so as to appear V-shaped in 
\cchisvetue section (Fig. 8d). The ‘V’ is wedged in between 
two chitinous plates of the tentorium (T) to be described later. 
In the anterior region of the clypeus, the ends of the operculum 
and the arms of the ‘V’ are drawn up towards the dorsal 
wall of the head, to “mae the clypeal folds (Fig. 8e). From 
the level of the anterior end of the salivary chamber, the 
ventral wall of pharynx is continued asa delicate spoon-shaped 
structure, the pharyngeal duct, along the middle line and enters 
the suction canal formed by the maxillary stylets. The latter 
enter the head and diverge apart to receive the tip of the 
pharynx. 
In the region of the pharyngeal duct, the operculum be- 
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