ANATOMY AND PHYSIOLOGY 95 
6. S. placodeum—a membranous plate, its outer surface 
continuous with the general integument (Fig. 123). Func- 
Figs. 116-125. 
Types of antennal sensilla, in longitudinal section (excepting Figs. 119 and 120). 
Fig. 116, sensillum ccloconicum; 117, celoconicum; 118, basiconicum; 119, stylo- 
conicum; 120, cheticum; 121, trichodeum; 122, trichodeum; 123, placodeum; 124, 
ampullaceum; 125, ampullaceum; c, cuticula; , hypodermis; n, nerve; s, sensory cell. 
Figs. 116, 118, 121, 123, 124, honey bee, Apis mellifera; 117, 119, 122, moth, Fidonia 
piniaria; 120, moth, Ino pruni; 125, wasp, Vespa crabro.—After SCHENK. 
