STRUCTURE, GROWTH AND ECONOMICS OF INSECTS 



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Fig. 31. — Sections through the proventriculus of Gryllus pennsylvanicus. (All 

 greatly enlarged.) i. Longitudinal section through the median denticles. 2. 

 Transverse section passing through two folds of the anterior division of the proven- 

 triculus. 3. Surface view of a portion of one of the dental folds showing the chi- 

 tinous partition and four of the transverse rows of teeth. 4. Transverse section 

 of proventriculus passing through the median denticles. 5. Transverse section of 

 fold cut in the region of the lateral denticles. 6. Lateral view of two adjacent inner 

 barbated lobes, hr., Bristles of anterior division of proventriculus; ch.p., chitinous 

 partition between dental folds; cm., circular compressing muscles; c.v., cardiac 

 valve; ep., epithelium; i.bl., inner barbated lobes; in., intima; l.d., lateral denticle; 

 l.t., lateral tooth; m.d., median denticles; m.t., median tooth; o.b.L, outer barbated 

 lobes; r.m., relaxing muscle. 



