HEMIPTERA. 
269 
rence ; and Nepa lias only one., of which hut few 
other instances are afforded by the class. 
The general forms and relative position of the parts 
described, will be well understood from an inspection 
of Plate XVIII. which represents the details of a 
characteristic example of each of the two great divi- 
sions of this order. 
Fig. 6 is a highly magnified view of an insect belonging to 
the heteropterous section, Pentatoma rafipes , a common Brit- 
ish species. The wings on one side are expanded, the others 
in situ. For greater perspicuity, the various segments, where 
covered by superincumbent organs, are represented by dots. 
H, the head ; a, a, the eyes \ b , the ocelli ; c, one of the an- 
tenna; ; T 1, upperside of the prothorax ; /' one of the pro- 
thoracic legs *, T 2, upperBide of the mesothorax ; S c, scutel- 
Ium greatly developed and extending over the metathorax 
and part of the abdomen ; /*, one of the hemelytra ; he , 
the leathery basal portion of the hemelytra ; hm, the mem- 
branous or apical portion ; Tone of the mesothoracic legs ; T 3, 
upper side of the metathorax, greatly reduced in size, sup- 
porting the wings (one of which is extended, W 2 ), and the 
metathoracic or third pair of legs V" — A, abdomen. — Fig. 7. 
The head and prothorax of the same insect seen from beneath ; 
a, the eye \ c, base of antenna; \ 7r, labrum or upper-lip, long, 
and transversely striated *, /&, the four-jointed lower-lip trans- 
formed into an elongated canal for the reception of four slender 
setas, gg y hh , which represent the mandibles and maxillae *, 
5, raised portion of the underside of the head, forming a gutter, 
in which the base of the labrum rests*, T 1, underside of the 
prothorax ; t base of one of the prothoracic legs ; Z, the cavity 
of the prothorax, into which the anterior narrowed part of the 
mesothorax (marked in fig. 6 by the letter z) is received— 
Fig. 8. Side view of the head, the respective parts lettered as in 
fig. 7. — Fig. 0. One of the anterior tarsi of Pentatoma rufipes, 
shewing the emargination at the base of the tibia, and the pul- 
villi attached to the base of the claws. 
