1916] Reflex " Bleeding'' of Epilachna 205 



bordered by a dark circle inside of which appears a transparent 

 spot that is bordered by a much smaller circle. The internal 

 anatomy of a pore (p. 206) shows what these various parts are. 

 In oblique views the inner circles (Figs. 2, 4 and 5) appear as 

 small wedge-shaped figures. 



The pores vary considerably in size. All of those on the 

 tibia (Figs. 1 and 5), all of those associated with hairs on the 

 femur (Fig. 1), and those on the thorax (Fig. 6) and elytron 

 (Fig. 7) are of about the same size. Those in the groups on the 

 femur (Fig. 4) are comparatively large, while those on the 

 tarsus (Figs. 2 and 3) are medium in size. Any one of these pores 

 is several times smaller than an olfactory pore (Fig. 1, olp). 

 The pores in the articular membrane (Fig. 8, pi) are about 

 equal in size to the inner circles of the other type of pore. The 

 tubes connecting with these pores have the same size. 



2. Internal structure. 



Sections through all the foregoing enumerated pores, except 

 those in the articular membrane, show that this type of pore is 

 connected with reservoirs. And furthermore, since both types 

 of pores are the external openings of hypodermal glands, these 

 structures may be designated hypodermal glands with and 

 without reservoirs. 

 (a) Hypodermal glands ivitli reservoirs. 



There is a great difference in appearance between the hypo- 

 dermal glands in old adult beetles and those in beetles emerged 

 a short time. 

 {1) Mature hypodermal glands. 



In sections through this type of gland, that part of the 

 structure to be noticed first is the reservoir (Fig. 9, r). It 

 appears as a round or sHghtly oblong, hght-colored cavity. An 

 efferent tube {e) runs from the surface of the chitin into the 

 reservoir and ends about one-third the distance from the bottom 

 of the reservoir. A dark-staining, granular substance is usually 

 seen around the end of this tube in the reservoir. It is now 

 easily seen that the diameter of the Hght spot in a superficial 

 view is equal to the diameter of the reservoir, and that the 

 transparent spot surrounded by a much smaller circle is the 

 same as the outer opening of the efferent tube. This opening is 

 in reality the pore. 



