208 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
in some sections that I could see cilia, but this point I could not settle 
to my satisfaction. There is a thin, but distinct, layer of connective 
tissue around the epithelium. The character of the epithelium is not 
the same throughout this upper division. In the lower part, when seen 
from the inner surface, the epithelium presents the appearance repre- 
sented in Fig. 32, the nuclei being oval, of nearly uniform size, and quite 
closely crowded together. Higher up the nuclei are further apart and 
vary considerably in their dimensions ; the outlines of the cells also ap- 
pear more clearly as pentagonal. Near the rounded tip the distance 
apart of the nuclei is still greater, and they are more irregular in size. 
In some of the specimens I have examined the whole upper division of 
the tube was crowded with bundles of spermatozoa. In one tube I counted 
over 200 bundles. 
The lower end of the upper division tapers off, the nuclei becoming 
smaller and even more crowded than in Fig. 32. The muscular coat ap- 
pears thin at first, but, increasing, soon acquires its full thickness, the 
cahber of the tube diminishing at the same time. A transverse section 
of this lower part of the vesicula (Fig. 34) shows that the epithelial 
cells are very much smaller than in the upper portion (compare Fig. 34 
with Fig 31, both being equally magnified -Lf 2 -); the walls, however, 
rendered very much thicker by the enormous muscular coat, Fig 34 Muc, 
the fibres of which appear to be exclusively circular. 
I have also made a complete series of sections through the posterior 
end of the abdomen of the male, some of which display very beautifully 
the relations of the parts, but these structures are so complicated that 
an elaborate investigation is necessary to secure a satisfactory interpre- 
tation of the sections. Therefore I must reserve the subject for another 
occasion. 
DIGESTIVE CANAL. 
Of the digestive canal I shall give a more complete histological 
description than I have of the other systems. Of the cavity of the 
mouth and of the oesophagus I shall say but little. The sabvary glands 
I have not studied at all, for want of proper material. Those in the 
cockroach have been described by von Basch, 291 and also in the more 
recent superb monograph of Kupffer. 292 Leydig 293 has made some valua- 
ble observations. The glands have likewise been studied in other insects 
by various authors, to whom I need not refer here. 
In order to render my description easier to follow, I will preface my 
account by a brief review of the divisions of the digestive canal in 
locusts; my own investigations having shown that the divisions adopted 
by the older authors, 4 and since generally introduced in all text-books, 
291 S. Basch : TTntersuchungen ueber das Chylopoetiache und Uropoetische System der Blatta orien- 
tals. Sitzber. Wien. Akad., xxxiii (1858), pp. 234. Speicheldriisen, p. 235, Taf. v, Fig. 11. 
292 Kupffer: Die Speicbeldriisen von Periplaneta orientalis und ihr Nervenapparat. Beitrage Anat.. 
Phys., C. Ludwig gewidmet, p. 64, Taf. ix. 
^Miiller's Arch., 1859, pp. 59-70. 
