DIGESTIVE SYSTEM X61 



respectively of the embryo ; and the mesenteron, or 

 middle portion, which alone is formed from the 

 primitive alimentary tract of the embryo. 



a. The stomatodoeTun has a chitinous cuticular lining, 



continuous with the cuticular. investment of the 



head ; and is divided into the following regions. 



i. The buccal cavity is lodged in the head, and its 



posterior wall is raised up to form an elongated 



fleshy tongue or lingua. 



The salivary duct opens by a median 

 aperture in the angle between the hngua and 

 the labium (fig, 30), 

 ii. The oesophagus is a narrow tube running from 

 the mouth through the nerve collar and along 

 the neck. It is laterally compressed in the 

 cervical region, 

 iii. The crop is a large thin-walled pyriform sac, 

 extending through the thorax and far into 

 the abdomen. It is not separated by any dis- 

 tinct line of demarcation from the oesophagus, 

 iv. The gizzard, or proventriculus, is a pyriform sac 

 with thick muscular walls. Within it is a 

 series of six large cuticular teeth, and behind 

 them six small elevations covered with setae. 

 Lay the gizzard open to expose the teeth. 



Fia. 30. — Feriplaneta americana. The male dissected from the right 

 side. The testes, which are very small in the adult, are not 

 figured, (c. h. h.) 



A, anus. A-TS, antennary lobe of snpra-oesophageal ganglion, with anten- 

 nary nerve cut short. C, crop. CGr, supra-cesophageal ganglion. CL, colon. 

 CK, anal cercus. CX, coxa. B, elytron. F, lemur. FG, frontal ganglion. 

 FJS", visceral nerve. G-, gizzard. GrP, one of the gouapophyses. G5, fifth 

 abdominal ganglion. H, hepatic ceecum. HT, heart. I, ileum. Ii, lingua. 

 LIT, nerve to labrum. LP, labial palp. M, mushroom-shaped gland. 

 MC,Malpighiancfieca opening into junction of mesenteron and ileum : they are 

 much longer and more numerous than indicated. MX), duct of mushroom- 

 shaped gland. MB, mesenteron. MN, maxillary nerve. MP, maxillary 

 palp. PK", labial nerve. PP, podlcal plate, dlagrammatically drawn. R, rec- 

 tum. S, sub-ceaophageal ganglion. SD, salivary duct just above its opening 

 into the mouth. SG-, salivary glands. SL, style borne by ninth sternum. 

 SH, salivary receptacle. ST, one of the abdominal stigmata. T, proximal 

 ]oint of the tarsus. TB, tibia. TB, trochanter. Tl. first thoracic tergum, 

 or pronotum. T3, third thoracic tergum, or metanotum. VG, visceral ganglion. 

 W, wing. 3, tergum of second abdominal segment. 8, tergum of eighth 

 abdominal segment. 



M 



