104 FAMILY V. — PENTATOMID^E. 



KKV TO SUBTRIBES OF PENTATOMINI. 



</. Second ventral at middle not produced forward in a stout spine or 

 tubercle. 

 6. Osteolar opening without a distinct auricle, but extended as a nar- 

 row tapering evanescent canal. Subtribe I, p. 104. 

 bb. Osteolar opening usually with a short curved auricle having a 

 rounded tip, but not extended as a canal, or if so, the canal very 

 short and ending abruptly. Subtribe II, p. 120. 

 aa. Second ventral at middle produced forward in a stout spine or 

 tubercle towards or between the hind coxae. Subtribe III, p. 156. 



Subtribe I of Pentatomini. 



Pentatomids varying much in size, but all having the body 

 oval, obtuse behind ; cheeks except in Peribalus, not or scarcely 

 longer than tylus ; pronotum with side margins entire and 

 humeral angles obtusely rounded, never spined (except in some 

 species of Thyanta) ; osteolar opening extended as a gradually 

 evanescent canal; second ventral without a forward projecting 

 tubercle or spine. Five of our 25 eastern genera of Pentatomini 

 belong in this group. 



KEY TO EASTERN GENERA OF SUBTRIBE I OF PENTATOMINI. 



a. Cheeks distinctly longer than tylus and usually contiguous in front 

 of its tip; pronotum with narrow smooth ivory-white margins; 

 length less than 10 mm. I. Peribalus, p. 105. 



aa. Cheeks not or scarcely longer than tylus; sides of pronotum not 

 edged with white. 

 b. Osteolar canal not extending beyond middle of its supporting plate; 

 upper surface, except in Chlorochroa, not finely densely rugosely 

 punctate. 

 c. Body beneath, especially the sides of abdomen, distinctly pubes- 

 cent; cheeks each with a raised pale line along the middle; frena 

 not reaching middle of scutellum ; smaller, not over 8 mm. 



II. Trichopepla, p. 107. 



cc. Body beneath not pubescent; cheeks without a pale median ridge; 

 frena extending beyond middle of scutellum; larger, length 10 

 or more mm. 

 d. Second and third joints of beak usually subequal in length, 

 fourth shorter; head longer than wide; color dull greenish-yel- 

 low. III. Rhytidolomia, p. 109. 

 dd. Second joint of beak distinctly longer than third, the latter sub- 

 equal to fourth; head, including eyes, as wide or wider than 

 long; color clear green. IV. Chlorochroa, p. 111. 

 bb. Osteolar canal continued as a ridge which extends obliquely to the 

 outer front angle of the supporting plate; upper surface finely, 

 densely rugosely punctate. V. Thyanta, p. 113. 



