104 Psyche [December 
Gelastocoris, and the last author describes the striations 
along these canaliculi. 
The main difference between the glands of Gelastocoris 
and those of the aquatic Hemiptera is in the position of 
their external openings. Whereas in the aquatic Cryptocer- 
ata the orifices lie at or near the base of the labium, in 
Gelastocoris they are located much farther posteriorly on 
the head. A comparison of Figure 1 with Figures 2 and 3 
points out this difference; Notonecta undulata and Bel - 
ostoma flumineum are used as representatives of the 
aquatic forms. 
Text-figure 1. Diagrammatic transverse or longitudinal section through 
the epithelium of the cephalic gland in an adult Gelastocoris. In this dia- 
gram the epithelium is folded double, so that the lumen appears much 
narrower than it actually is. The canaliculus of the upper middle large cell 
is shown opening onto the lumen of the gland; the other canaliculi are 
diagrammed in transverse or oblique section. 700 X. 
Abbreviations used in figure: C — canaliculus; I — intima; LC — 
large cell; SC — small cell. 
The function of the cephalic glands in the water bugs 
has not yet been satisfactorily established. Previous work- 
ers have suggested (1) that their secretion is used in sub- 
