210 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
surface is thrown up into six longitudinal folds, the rectal glands, three 
of which are found in each half-section. The rectum opens into the 
short anal tube, An., which opens externally on the back just in front of 
the upper clasper. 
Crop. — Both divisions have their walls composed of the same layers: 
1, an internal chitiuous cuticula, which forms the hard covering of the 
ridges; 2, the underlying epithelium, the matrix of the cuticula, which 
seems to be pigmented, but unfortunately is not very distinct in my 
preparations ; 3, an inner layer of longitudinal muscles ; and 4, an exter- 
nal layer of circular muscular fibres. The muscular fibres of the crop are 
all striated. There is a Layer of connective tissuebetween the muscles and 
the epithelium (Wilde), making five layers in all. As it is not distinct in 
my preparations I do not enumerate it with those I have myself made 
out. In the front division the ridges are transverse, somewhat irreg- 
ular, but each one continuous and not formed of single teeth ; they 
are much more numerous and closely crowded in femur-rabrum than in 
spretus. The inner covering of the ridges is the thick cuticula. Upon 
the posterior edge of each ridge there is a row of sharp chitinous spines 
which point inwards and backwards. The ridges are not all parallel, as 
is shown in Fig. 45. Those next the oesophagus are broader than the 
rest and are armed with several rows of spines. The posterior ridges 
become first slightly irregular, then zigzag, and so gradually change 
their direction until they become longitudinal and very regularly paral- 
lel. The area where the ridges are zigzag marks the limit between the 
two divisions of the crop. The two muscular layers are well developed 
in the front division, the longitudinal, which are of course transverse to 
the ridges, being particularly powerful. 
The posterior segment of the crop, Fig. 45, GV. 2 , has longitudinal ridges. 
In a transverse section, Fig. 35, it is seen that the ridges are small, rid., 
rounded on top, with small projecting cuticular spines of yellowish color, 
s, s. In each ridge the pigmented epithelium appears as a dark layer 
underneath thecuticula. The inner muscular coat, X, of longitudinal fibres 
is but little developed in comparison with the enormous coat of circular 
fibers, mac. C. Thus we see that, in both parts of the crop, that muscu- 
lar coat obtains predominance whose fibres run transversely to the direc- 
tion of the ridges. An examination of the inner surface of the hind 
part of the crop reveals the fact that the ridges are not continuous, but 
composed of rows of imperfectly individualized oblong teeth, each of 
which is armed with a few small spines. 
It will be seen that the general character of the crop is the same as 
in the cockroach, according to the descriptions of Basch, 294 who adds that 
the epithelium corresponds to Bamdohr's "flockige-Lage? and is the 
same as the membrana propria of Straus-Durckheim and Burmeister. 
Finally, I must call particular attention to the recent capital memoir 295 of 
<**S. Basch. Sitzher. Wien. Akad. (1858), xxxiii, p. 242. 
296 K. F. Wilde? Untersuchungen iiber den Kaumagen der Ortbopteren. Arch. f. Naturgesch. 
Jahrg. xliv, l.Bd., p. 135 (1877). 
