PRIMARY DIVISIONS OF THE DIGESTIVE CANAL 299 



insect ; i.e., the fore-intestine (stomodceum of the embryo), mid-intes- 

 tine or " chyle-stomach," and hind-intestine or proctodceum (Fig. 300). 



Mid-intestine (Mesenteron). 

 Hind-intestine (Proctodaeum) . 



FIG. 300. The three primary divisions of the alimentary canal of an embryonic orthopterous 

 insect : br, brain ; sbff, suboesophageal ganglion ; ng, nervous cord ; at, stomodseum ; pr, procto- 

 difum ; IH-P, malphigian tubes; metten, niid-intestine ; ht, heart; md, mandibles; mx, mx',lst 

 and 2d maxilloe. After Ayers, with some changes. 



The three primary regions, with their differentiations, may be tabu- 

 lated thus : 



Fore-intestine (Stomodaeum). Mouth and pharynx. 



Pumping apparatus of Hemiptera, 



Lepidoptera, and Diptera. 

 (Esophagus. 

 Crop or ingluvies, food reservoir, or 



"sucking stomach." 

 Proventriculus. 

 Mid-intestine, " chylific stomach," or 



ventriculus (with crecal glands). 

 Ileum, or short intestine (with the 



urinary tubes). 

 Long intestine. 

 Colon. 



Rectum (with rectal glands). 

 Anus (with anal glands). 



The appendages of the alimentary canal are : (1) the salivary and 

 poison glands, which arise from the stomodaeum in embryonic life ; 



FIG. 298. Internal anatomy of Melanoplus femttr-rubrum : at, antenna and nerve loading 

 to it from the "brain" or supra-cesophageal ganglion (p) ; oo, ocelli, anterior and vertical ones, 

 with ocellar nerves leading to them from the brain ; ce, oesophagus ; m, mouth ; ll>, labium or under 

 lip ; if, infra-oesophageal ganglion, sending three pairs of nerves to the mandibles, maxillae, and 

 labiutn respectively (not clearly shown in the engraving) ; , sympathetic or vagus nerve, starting 

 from a ganglion resting above the oesophagus, and connecting with another ganglion (sg) near the 

 hinder end of the crop ; sal, salivary glands (the termination of the salivary duct not clearly 

 shown by the engraver) ; nv, nervous cord and ganglia ; ov, ovary ; ur, origin of urinary tubes ; 

 ovt, oviduct ; sb, sebaceous gland ; bo, bursa copulatrix ; ort, site of opening of the oviduct (the 

 left oviduct cut away) ; 1-10, abdominal segments. The other organs labelled in full. Drawn from 

 his original dissections by Mr. Edward Burgess. 



FIG. 299. Digestive canal of Anabrus : m, mouth: ce, oesophagus; sm, the sympathetic 

 nerve passing along the crop ; t, tongue ; fg, frontal ganglion ; br, brain, the nervous cord passing 

 backward from it; fir, salivary reservoir; ng, salivary gland; pv, proventriculus ; ur; origin of 

 urinary tubes; sb, sebaceous gland ; 1-10, the ten abdominal segments. Burgess del. 



