1NSI-.C T.V 





/... i:i 



Alimfntnry cannl'vf Carabtu monilif. 



h, o?sophagus ; i, gizzard, or provrnlriculus ; A, 

 vrntriculus or digestive stomach; I, ilium \ m n, 

 colon, with cacal glands ; a, rectum ; p, hepatic 

 vessels ; '/, their point of insertion ; s, anal ves- 

 sels ; a, l>, r, a gastric vessel j a, 6, a portion of the 

 lining of the gizzard. 



examined by transmitted lif-lit, there is a slight 

 appearance of circular fibres. Its texture 

 throughout is distinctly muscular, both longitu- 

 dinal aud transverse muscular fibres being dis- 

 tinctly visible in every part of it, and of nearly 

 uniform size. Tins is a remarkably low furm 

 of development in an iiiMvt which kfttrwaida 

 becomes one of the most perfectly prtjBnized "I 



it* class. Tin: next wnpto form o( . 



ran.il ix:urs in the hamr onler nf n 

 tliu larva of tli<< roininon Ilnrnrt, I < <; . 

 in which it consists nf a straight and uradna'lv 

 m;; tube, extruded as far iKickwards a< 

 the eleventh M ','iniMil, uheie it h. . 

 stricted, and forms a short small int 

 receiving at the same time the ins, -m 

 very minute hepatic vessels, after which the 

 intestine becomes aj^iin slightly enlarged to 

 form a rudimentary colon. The next snmrniut 

 more developed form is found in the Aftitltr, as 

 in A>it/ii>]>/wr<i retmui, in which the canal forms 

 a distinct (esophagus, which terminates in a very 

 slight dilatation, and then gradually in! 

 passes onwards, as in the Hornet, until it ac- 

 quires its largest diameter in the eleven: 

 ment, and becomes constricted to form the 

 small intestine, receiving laterally at the same 

 time the insertions of the hepatic vessels. The 

 small intestine then passes forwards, and all. r 

 making one short sigmoid turn backwards, ends 

 in a straight colon and anal aperture, which is 

 distinctly developed in this insect towards the 

 latter part of the larva period, at which time, 

 after the insect has become full grown and 

 ceased to feed, we have observed fauces pawed 

 from it, but we have reason to believe that the 

 anal aperture is not developed until that pennd, 

 since no fx-ces arc found in the cell in which 

 the larva is inclosed until after the larva is (nil- 

 grown, and has eaten the whole of the food that 

 was stored up with it when the cell was closed 

 l>y the parent. In the larvae of some ColrojH 

 tera, as in the iMiiiellicoriics, there is aim 

 simple a form of the alimentary canal as in the 

 Apidic. In these, as in Melulonllia vulgarit, 

 (jig. 425,) it commences in a short and narrow 

 (esophagus, which opens by a valve into a very 

 capacious stomach that extends backwards to 

 the twelfth segment of the body, where it is 

 gradually decreased in size, and ends in a nar- 

 rowed pylorus, which is divided internally by 

 a valve from a short and narrow intestine, 

 that passes forwards beneath the stomach, 

 and ends in a very large colon, which at us 

 commencement is dilated into an imnii IIM 

 coecum, and is in general distended with fscces. 

 It terminates beneath the middle of the 

 posterior half of the stomach in a rectum, 

 which passes directly to an anal aperture. 

 In our dissection of this larva we did not obs, m- 

 the exact pointat which the biliary vost'ls cut. r, 

 but nevertheless they exist, although less distinct 

 than in the perfect insect. They were observed 

 by Swammerdam in the larva of Orycta mui- 

 cornii* entering, four in number, at the pylo- 

 rus. In this and other lamellicorn larva' the 

 surface of the digestive cavity is increased by 

 the addition of three series of cereal appen- 

 dages. The first surround the cardiac i \trr- 

 mity, and consist of twelve cujcal mix's, with 

 their apices directed forwards, and dilated on 

 each side into four smaller cceca, so that each 

 one has somewhat the appearance of a fern- 

 leaf. From the situation which they occupy, 

 these may perhaps be n-\ranlcil a.s salivaiy 

 organs. A little beyond the insertion of these 



* Biblia Nat. tab.xxvii. fig. V. e. 



