136 ANATOMY. 



attached to each other, but frequently in the ilium, particularly when 

 the muscular membrane is very delicate (Lamia cedilis} *, they leave 

 a considerable space between them. Here and there also the muscular 

 membrane is thicker than in the stomach, which may possibly be 

 explained by the distribution of similar fasciculi of fibres over a nar- 

 rower space, whereas in those cases in which this intestine is as 

 distended as the stomach (for example, Lamia a'dilis,') the muscular 

 membrane of both is uniform in its consistency. 



The passage of the stomach into the duodenum is formed by a dis- 

 tinct constriction, which supplants a sphincter, or is possibly one ; the 

 ring thus projecting internally is called pylorus, immediately beyond 

 which the mouth of the gall vessels pierce the intestinal membranes. 



This intestine is also separated into different divisions by means of 

 constrictions, which have different functions, and have consequently 

 received different names. 



The first of these divisions is called the DUODENUM according to Ram- 

 dohr, but it is scarcely analogous to the similarly named portion of the 

 intestinal canal in the superior animals, but it more probably entirely 

 belongs to the following ilium. In the few beetles in which it has been 

 hitherto observed (Sitpha, Necrophorus, Melolontha, Lampyris] it 

 generally appears as a short, smooth tube, of equal width, or narrower 

 (Melolontha} than the ilium, from which it is distinguished exteriorly 

 by the ringed constrictions of the latter (Necrophorus^, Silpha J). A 

 stronger ringed constriction separates it from the following portion of 

 the small intestines. 



107. 



THE ILIUM. 



Wherever the duodenum is wanting the ILIUM (PI. XVII XXII. 

 E, E,) follows immediately upon the stomach, from which it is separated 

 by the above described pylorus. This portion of the intestine is likewise 

 sometimes wanting, so that the stomach lies immediately contiguous to 

 the colon (Libellula\, Reduvius ||). This appears to be the general 

 rule of structure in the bugs; and when even occasionally a small 

 portion of the intestine is found beyond the stomach in which the 

 biliary vessels bury themselves, it is nevertheless so inconsiderable 



* R^m.lohr, PI. IX. f. 6. f Ib., PI. V. f. 1. : Ib., PI. IV. f. 2. 



Ib., PI. XV. f. 4. || Ib., PI. XXV. f. 5. 



