THE ORGANS OF NUTRITION. 131 



secretory organs which evacuate themselves at the very commencement 

 of the stomach, closely behind the cardia *. They are doubtlessly the 

 same forms we shall more fully describe below in the Orthopterja, and 

 which have been considered as the analogues of the pyloric caecum of 

 the pancreas, or liver. 



The Neuroptera have a short, sometimes smooth, sometimes trans- 

 versely striated cylindrical or conical stomach, in front of which, at 

 least in Myrmecoleon and Panorpa, there is a distinct proventriculus. 

 This is wanting in the Libellulee and Ephemerae: their stomach is 

 long, cylindrical, and separated from the pharynx by a slight con- 

 striction only. Lepisma, which genus, as well as the two families of 

 Termites and the mandibulate parasites, I unite in the order Dicty- 

 otoptera, has a very small stomach, and in front of it a proventriculus 

 armed with six teeth, contiguous to which lies a broader and larger 

 crop. The same is the case in the Termites, but their stomach is 

 longer. The Mallophaga t have also a tolerably large crop, but the 

 true stomach is small, and is provided beyond the cardia with two con- 

 siderable points ; perhaps they, as well as the genus Psocus, for both 

 devour hard materials (the former, for example, feathers), are also 

 furnished with a proventriculus. 



The three remaining orders display stomachs of a much more complex 

 form than the preceding. 



In the Coleoptcra we find a considerable variety in the structure of 

 the stomach, we observe the most simple in those Lamellicornia which 

 feed upon feculent substances, or upon the juices of flowers (for ex., 

 Scarabcens, PI. XX. f. 2., Melolonlha, Trichius). In these the short 

 and narrow oesophagus passes, without any distinct indication of its 

 termination, gradually into a very long, cylindrical, and equally wide 

 stomach. The object of this great length of the stomach is evidently 

 to prepare the food more fully for assimilation, for in the larvae of 

 these insects it is much shorter, but in compensation it is supplied at 

 both ends with blind, pointed appendages (organs of secretion), of 

 which, in some cases (for example, Ulster, a genus closely approximate 

 to the Lamellicornia,} traces still remain in the perfect insect. Next 

 to these, the tribes which feed upon fresh vegetable matter, and parti- 

 cularly the juices of flowers, the Chrysomelina and Cerambycina, have 



* Bombylius, Leptis, Chrysotoxum, see Ramclohr, PL XX. and XXI. 

 f Ch. L. Nitzsch, in Germar's Magaz. der Entomol., vol. iii. p. 280. and vol. iv. 

 p. 277. 



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