NUTRITION PROPER. 



337 



also the same in another insect (Belostoma) to show the 

 variations, and especially to show the salivary glands, 

 not shown in the previous figure. The distinctive func- 

 tions of these several parts are somewhat doubtful. 

 The most probable view is given in the legends. 



We have given the simplest case of a carnivorous bee- 

 tle. In many insects, especially the herbivorous, like the 

 grasshopper (orthopter), the digestive apparatus is much 

 more complex and the 

 intestines much longer 

 and more convoluted. 



It is well to remark 

 that what we have called 

 the biliary or Malpighi- 

 an tubes are also, appar- 

 ently, uriniferous tubes 

 as well. These two func- 

 tions are not yet well 

 differentiated. The sig- 

 nificance of this will ap- 

 pear hereafter. 



Crustaceans: 

 Mouth Organs. — We 

 have already seen (page 

 268) that these are all 

 modified appendages of 

 the anterior somites. 

 Four pairs, called max- 

 illipeds, are food gather- 

 ers, and two pairs, max- 

 illa? and mandibles, di- 

 vide and chew the food 

 (see Fig. 170). 



Stomach. — The stomach is situated in the anterior 

 part of the cephalothorax, immediately above the 



Fig. 221. — Lobster with the carapace 

 taken off : st, stomach ; dotted tube, 

 ii, intestines; Z, liver; H, heart. 



