322 ERNEST WARREN. 



surface of the cliitin and form actual pores. Even if definite 

 pores are not present, the existence of the cracks or canals 

 would materially assist in the slow filtration of fluids or gases 

 through the somewhat thick chitiu. The lack of a clearly- 

 marked porosity is doubtless associated with the ever-present 

 danger of desiccation. 



It is instructive to note the places in the body where the 

 chitin was found to be especially stainable with hajmatoxylin. 

 These were, in descending order of staining intensity : 



(1) A complicated frill on the venti-al sui-face of the pro- 

 thorax (PI. XVIII, and XVII, fig. 34) ; here the epistracum 

 and endostracum tended to be remarkably separated from 

 each other, and the relatively thick hypodermis was separated 

 from the endostracum by a granular stainable substance. 



(2) The dorsal anterior bilobed swelling of the prothorax, 

 overhanging the back of the head; the terminal portion 

 stained more especially (fig. 30). (3) The backwardly directed 

 swellings of the metathorax (fig. 32). (4) The ventral surface 

 of the abdominal stalk and the loAver surface of the swollen 

 abdominal segment III. These various places are favourably 

 situated as regards accessibility to the termites, and it is 

 probable that substances derived from the blood-tissue exude 

 over these areas. 



Around the base of the larger setfe there may be a circular 

 crack leading into the space between the general cuticle and 

 hypodermis (PI. XVII, fig. 38). Doubtless the body-fluids 

 can exude through these perforations. 



The Hypodermis. — The hypodermis or epidermis varies 

 greatly in thickness in different parts of the body. It is 

 usually one cell thick, and consequently the varying thickness 

 depends on the depth of the individual cells. Under the 

 abdominal sternites the hypodermis may be more than one 

 cell thick (PI. XVI, fig. 9). In some parts of the body the 

 hypodermis is withdrawn away from the cuticle more or less 

 considerably, and the resulting space contains a coagulated 

 substance readily stainable with hasmatoxylin (PI. XVII, 

 fio-. 32, cg.m.). According to Trjigardh it is this substance 



