THE ALIMENTARY CANAL AND ITS GLANDS. 



97 



vagina ted into the posterior end of the honey stomach. Each lobe 

 of its mouth forms a thick triangular ridge on the walls of its 

 lumen, in which lies a special mass of longitudinal muscle fibers 

 (LMcl) . The epithelium of the lumen is lined by a thick, smooth, 

 chitinous intima (Int), while the lobes of the mouth (nn) are pro- 

 vided with bristles point- 

 ing inward and backward 

 into the mouth opening. 



The posterior opening 

 of the proventriculus into 

 the ventriculus is guarded 

 by a long tubular fold 

 of its epithelium (fig. 45, 

 PventVlv), the pro ventric- 

 ular valve. This would 

 appear to constitute an 

 effective check against the 

 escape of any food back 

 into the proventriculus. It 

 looks like one of those traps 

 which induces an animal to 

 enter by a tapering funnel 

 but whose exit is so small 

 that the cajDtive can not 

 find it from the other side. 

 Yet Schonfeld has elab- 

 orately described experi- 

 ments by means of which 

 he induced the ventriculus 

 to discharge its contents 

 through the proventriculus 

 into the honey stomach and 

 even into the end of the 

 oesophagus. He says that 

 he did this by gently tap- 

 ping on the honey stomach 

 and the ventriculus at the 

 same time. The experiment 

 was repeated manj' times with unvarying results and Schonfeld de- 

 scribes so minutely what happened that we can not disbelieve his 

 statements. From these experiments he argues that the larval food- 

 stuff is prepared in the stomach and regurgitated through the proven- 

 triculus directly into the oesophagus by a contraction of the honey 

 stomach which brings the stomach-mouth against the base of the oesoph- 

 22181— No. 18—10 7 



\fent 



,-LMcl 



-TMc] 



Fig. 45. — Longitudinal median section of base of 

 cesopliagus ((B),lioney stomaeli (7/S), proventricu- 

 lus (.Pvent) and ventriculus {Vent) of a queen. 



