1925] External Anatomy of Head and Abdomen of the Roach 205 
naria,” instead of the original form antennale). The basal 
segment or scape sc of Figs. 5 and 7 is borne on a process af 
originally called the antennifer, for which designation Yuasa 
substitutes the term “antacoila.” On each side of the antenni- 
fer af of Fig. 7 is a small basantennal plate to which is attached 
a basantennal tendon labelled tn in Fig. 9. When the muscles 
attached to these tendons contract, they move the antennae, 
using the tip of the antennifer af as a fulcrum, as shown in Fig. 
9. Above the base of the antenna is a surantennifer saf which 
connects the base of the antenna above, with the antennal sclerite 
ban, and assists in the complicated movements of the antenna, 
which is capable of great freedom of movement ,as is necessary 
in a structure bearing the delicate chemical-sense organs and 
tactile organs of the “feelers.” As is shown in Fig. 7, the scape 
sc articulates with the pedicel yd at a point indicated in the draw- 
ing, and a similar articulating point is located on the other sur- 
face of the antenna. Between these two “rocking points” are 
small chitinous pedicellar plates embedded in the connecting 
membrane, furnishing points of attachment for certain of the 
muscles operating the antennae. Beyond or distal to the pedicel 
yd is the postpedicel yyd, and distal to this are the segments of 
the flagellum or filament, as the remainder of the antenna is 
called. The relative sizes of the pedicel, postpedicel etc., vary 
with the sex of the individual, but these slight sexual differences 
have not been dealt with in this paper. The flagellum is compos- 
ed of four principal types of segments. Those in the proximal 
portion of the antenna are the brachymeres or shorter segments 
(i. e. a and b of Fig. 6), while those in the distal portion of the 
antenna are the dolichomeres or longer segments (i. e. c and d of 
Fig. 6). We may further distinguish the short or annular brachy- 
meres a from the long brachymeres b, and the stout dolichomeres 
c from the slender dolichomeres d, though the types merge, and 
are rather difficult to describe. 
Turning next to the consideration of the abdomen: as shown 
in Fig. 14, there are eight spiracle-bearing segments followed by 
what appear to be three non-spiracle-bearing segments (the ter- 
minal ones) best seen in the dorsal region of the abdomen. The 
typical segments (in the middle of the abdomen) consist of a dor- 
