642 E. N. PAVLOVBKY 



aphids, gnats (Nuttall and Shipley, lllOB), and many others). 

 This likeness may be explained by a convergence, caused 

 by such a typical action, from the physical point of view, as 

 the suction of liquids. 



The gastric fluid (black in colour), which is poured over 

 the seized prey, is regurgitated from the stomach under the 

 influence of an antiperistaltic movement of its walls. The 

 regurgitation is favoured by the absence of any adjacent 

 cardiac valves. 



The mid-gut or stomach has, as has been pointed out by 

 Portier, many short blind papillae, or cryptae, formed by the 

 evagination of the epithelial wall of the intestine into the body- 

 cavity. On my preparations closely set mitoses of the epithe- 

 lium were also visible. 



It is instructive to compare the size of the cells of the intestine 

 in just emerged and mature larvae of H. caraboides. 

 A better representation than any description can be given by 

 figs. 3 and 4 (PI. 27), made at the same magnification. On the 

 longitudinal section of the crypt (PI. 27, figs. 8, 4, crp) of a young 

 larva the number of cells is counted by units, and in the 

 mature larva by tens. The cells themselves are much larger 

 in the latter ; the association of these causes has an intluence 

 on the size of the cryptae. The nuclei of the cells of the cryptae 

 and the intestine itself in larvae of different age differ in size 

 from each other comparatively less than the size of the cells 

 themselves. The latter fact depends upon the real growth 

 of the cells as well as their secretive action. 



The growth of the cells in dependence on the growth of the 

 larva is best demonstrated in the muscular fibres of the cover 

 of the intestine. In the larva of the first stage the muscular 

 fibres are very thin (PI. 27, tig. 3, mt) ; whereas in the mature 

 larvae they are fifteen to twenty times stouter (PI. 27, fig. 4, mt). 

 This growth is explained by the increase of the myofibrillae, 

 which are differentiated in the sarcoplasm of the muscular cells. 

 The lack of material did not allow me to study the question 

 of the regeneration of the intestinal epitlielium. which in the 

 adult beetle is periodically cast off and replaced by a new one. 



