ON THE MECHANISM OF SUCTION IN LYGUS PABULINUS. 707 
Kocchi (6) has the special advantage of a simple terminology, 
which I have accordingly adopted here. 
Text-figure 16. 
Lygus pabulinus. 
Transverse section, showing the piston, the afferent salivary duct, the divaricators, 
the protractors of the stylets, the labial muscle, ete. Ob. 3 & Oc. 4. 
For explanation of the lettering see p. 693. 
The endoskeleton of Lygus pabulinaus consists of hollow chitinous 
rods which are covered by a thin hypodermal (chitinogenous) 
layer. They are nothing but involutions of the chitin of the 
head, and therefore are called “ Apodemes.” The fact that the 
tentorium consists of these hollow structures is very significant. 
