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TEXT-BOOK OF ENTOMOLOGY 



In the mole-cricket the hinder part of the crop is armed within 

 with hook-like bristles directed backwards so as not to prevent the 



energetic pressure of the food backwards 

 into the proventriculus, and to obviate the 

 possibility of a regurgitation. (Eberli.) 



The fore-stomach or proventriculus. This 

 is especially well developed in the Der- 

 maptera, in the Orthopterous families 

 Locustidae, Gryllidae, and Mantidse, while 

 in the Thysanura (Lepisma) there is a 

 spherical gizzard provided with six teeth. 

 It also occurs in many wood-boring in- 

 sects, and in most carnivorous insects, 

 notably the Carabidae, Dyticidae, Scolyt- 

 idee, in the Mecoptera (scorpion-flies), in 

 the fleas, and in many kinds of ants, as 

 well as Cynips, Leucospis, and Xyphidria. 

 It is very muscular, lined within with 

 chitin, which is usually provided with 

 numerous teeth arising from the folds. 

 These folds begin in the oesophagus or 

 crop, and suddenly end where the mesen- 

 teron (" chylific stomach ") begins. It has 

 been compared with the gizzard of birds, 

 and is usually called by German authors 

 the chewing or masticating stomach. 

 (Kaumagen.) 



The proventriculus is best developed in the 

 Gryllidte (Acrida viridissima) , where the six folds 

 at the end of the crop close together to form a valve 

 between the crop and proventriculus. "They 

 are each armed with five very minute hooked 

 teeth ; and, continued into the gizzard, develop 

 many more in their course through that organ. 

 These first teeth are arranged around the 

 entrance to the gizzard, and seem designed to 

 retain the insufficiently comminuted food and to 

 pass it on to that organ. 



"Next to these in succession on each of the 

 longitudinal ridges are four fiat, broad, somewhat 

 quadrate teeth, each of which is very finely den- 



FIG. 309. Digestive canal of SjJi/n.r //,/nx/ri: h, o-soph- 

 agus ; i, rudiment of the gizzard; k, "stomach"; </. it" 

 pyloric end; /.food reservoir; j>, urinary tubes; I, ilium; 

 ii>, I'lecum of colon ; , rectum ; v, vent. After Newport. 



