OF DIGESTION. 351 



portionally longer, and project beyond the anterior four-lobed portion 

 called by entomologists the tongue. At the base of the labium lies 

 the pharynx, covered by a triangular valve, which Treviranus * calls 

 the second tongue ; but it is impossible that this valve should be a 

 tongue, as it lies over the orifice of the pharynx, and evidently serves 

 to close that organ, comparable in form and function to the uvula of the 

 mammalia. The sucking stomach is not so distinctly separated from 

 the oesophagus, but rather an anterior crop-like distension of it (see 

 103), and into this crop the funnel-shaped orifice of the mouth pro- 

 jects. When it distends itself this orifice of the stomach approaches 

 closer to the upper thinner commencement of the oesophagus, and the 

 passage of the food into the stomach is thereby promoted. This dis- 

 tension also causes the ascent of the honey into the oral tube, and when 

 it has arrived at the pharynx deglutition passes it on. Treviranus has 

 convinced himself of the correctness of considering this crop as a suck- 

 ing stomach, as well as of its corresponding function, or at least of that 

 of a similar appendage to the oesophagus of the majority of haustellate 

 insects, by dissecting them alive ; he always found this bladder empty, 

 and it, as \vell as the pharynx, in a peristaltic motion, or interchanging 

 distension and contraction, which was likewise observed before him by 

 Malpighi f and Swammerdam J, who, however, did not detect its 

 function. According to Meckel the sucking bladder contains also, at 

 least in the Diptera, fluids of different colours ; Ramdohr || calls it a 

 food bag, and ascribes it exclusively to the Diptera. But whosoever 

 shall follow Treviranus in his description, without predilection or pre- 

 conceived ideas, must, I am sure, be speedily convinced ; it would be 

 absolute obstinacy, after such clearness and such a distinct insight into 

 the suctorial apparatus of insects, to require further proofs ; an hypo- 

 thesis which explains everything is no longer an hypothesis even if, as 

 however is not the case here, it is not supported by observation. 



Let us turn to the bees, in which, with a very similar form of the 

 oral apparatus, it is however more difficult to comprehend their mode 

 of sucking. Instead of a lobate tongue we find in the bees a long, fili- 

 form, hairy, hollow proboscis, which at its base has two membranous 

 lobes (Latreille's Paraglossa, PL VI. f. 7- a, ) ; the aperture of the 



* Vermischte Schriften, vol. ii. p. 134. 



t Opera Omnia, Lugd. Bat. 1687, torn. ii. p. 44. 



J Biblia Naturae, p. 138. a. Vergl. Anat. vol. iv. p. .92. 



|| Abh'and. uber die Verdauungswerk/. p. 1 1 . 



