50 
Psyche 
[June 
Euformicinae) , under which Emery grouped seven of the 
twelve formicine tribes recognized by him, and including 
Camponotus, the proventriculus is divided into four dis- 
tinct parts: the calyx, the occlusory tract (“valve” of 
Emery) , the bulb, and the cylinder (pi. 5 ; A, B, C, D) . The 
calyx is composed of four strap-like, chitinous rods, or 
sepals, which extend anteriorly from the body of the 
proventriculus to capture part of the posterior wall of the 
crop. It acts like a collapsible funnel which can be closed 
by the combined action of its intrinsic muscles and the 
posterior ring muscles of the crop. Seen in cross-section, 
each sepal is morphologically differentiated into two zones 
(plate 6, fig. A), which represent two successive phases 
of secretion by the underlying epithelial cells. The inner 
area is composed of closely approximated chitinous hairs, 
which lend it a finely and evenly striated appearance. The 
outer zone also appears striate, but coarsely and unevenly 
so, and it is not composed of independent hairs. This area 
incloses medially the sepal canal, which is to be distin- 
guished from the lateral solid wings of the sepal. The canal 
opens through a narrow slit to the calyx cavity; this slit 
is a cross section of the longitudinal cleft which extends 
the full length of the sepal. It is guarded by fine, loosely 
i iterdigitating chitinous hairs (collectively designated as 
the filter) , which are actually structural hairs of the inner 
area of the sepal that have been separated from one 
another. The canal narrows gradually in the anterior end 
of the sepal and finally ends blindly; it does not extend 
into the cavity of the crop. The bulk of the calyx wall 
is made up of epithelium, designated according to position 
as sepalary or inter sepalary. Externally the wall is limited 
by a layer of striated muscle, one to two fibers thick, which 
attaches to the sepals themselves. Between the points of 
Explanation of Plate 6 
Fig. A, cross section of the calyx at approximately the level of trans- 
ection shown in plate 6. Fig. B, cross section of the occlusory tract at 
slightly above the level of transection shown in plate 6. Filt., sepal 
filter; sep. cnl, sepal canal; epth., intersepalary epithelium; sep. epth., 
sepalary epithelium; c. mcl., circular muscle fibers; 1. mcl., longitudinal 
muscle fibers. (360X) 
