338 



H. C. VAN DER HEYDE 



The method of respiration of Hydrophilus is entirely different ; 

 itjs, however, not my purpose to enter into details with regard 

 to^this species in the present paper. 



Above all, it seemed desirable to me to study the breathing 

 mechanism on the intact animal. Curves such as have been 

 traced by Babak^ may give rise to the objection that they do 



Fig. 1. Apparatus for the registration of the respiratory movements of 

 Dytiscus. 



not represent the normal breathing mechanism of the beetle. 

 This author made an opening in the elytra, fixed the animal 

 with pins, and fastened a booklet in its back. In that way he 

 could register the movements of the back on a kymograph. 

 The great difficulty however, which must be surmounted is the 

 fact that the whole respiratory apparatus is completely covered 

 by the large elytra. On the suggestion of Professor Buytendyk, 

 I finally used the apparatus of figure 1. 



8 Prof. Dr. Edw. Babak. Mitw. stud. med. J. Hepner. Untersuchungen liber 

 die Atemzentrentatigkeit. I. Ueber die Physiologie der Atemzentrentiitigkeit 

 von Dytiscus mit Bemerkungen iiber die Ventilation des Tracheensystems. 

 Pfluger's Arch., Bd. 147, S. 349, 1912. 



