274 HACHIRO YUASA 



cephalad from the cephalic margin of each circular area, bears 

 about fifteen, short, conspicuous, subdecumbent, spine-like 

 setae. The surface of the epipharynx between the two brown- 

 ish areas and the area cephalad of them is densely and uni- 

 formly covered with short fine spinulae, the majority of which 

 are directed more or less mesocaudad. The cephahc emargina- 

 tion of the epipharynx is beset with stiff, brownish spinulae. 

 The epigusta is flat or slightly concave, and is uniformly covered 

 with short fine spinulae or solid 'hairs.' The ambipharnyx is 

 rather broad, smooth, and thinner than the adjoining coriae. 



The parapharynx is linguiform and its various parts are well 

 differentiated. The pharyngea is the long, slender sclerite along 

 each side of the subgusta. Its caudal portion is expanded, less 

 chitinized, and extends dorsocaudad, supporting the lateral 

 wall of the postpharynx. The entrance to the latter is located, 

 therefore, near the middle of the pharyngeae. The paralingua is 

 the convex subquadrate sclerite fused to the cephahc end of 

 each pharyngea and extends caudoyentrad. A long, narrow, 

 crescentric sclerite, the linguacuta, lies near the caudal angle of 

 each paralingua. It extends for a short distance dorso-caudo- 

 laterad and merges into a slender ental tendon, the linguatendon, 

 which, after passing over the dorsal side of the rectotendon of 

 the mandible, extends into and toward the lateral side of this 

 structure. Mangan ('08) figured, for the first time, this tendon 

 in Periplaneta australasiae. The lingula is the subcrescentic 

 brownish sclerite fused to the cephalic end of and dorsad to each 

 paralingua. , It is sparsely covered with short, distinct, spine- 

 like setae. The mesal end of the lingula is produced meso-entad 

 and approaches the one on the other side, but remains separate 

 on the meson. This part of the lingulae produces the constriction 

 of the propharynx between the basipharynx and hypopharynx. 

 The membranous area caudad of the mesal arms of the lingulae 

 is convex and slightly elevated, forming a ridge which is pro- 

 vided on each side with a band of brownish spinulae. Bugnion 

 ('16) erroneously designated and figured this ridge in Blatta 

 americana as 'I'entree du pharynx.' There is a group of small 

 distinct sensory pits on each side and shghtly cephalad of the 



