SUBFAMILY I. — PENTATOMIN^E. 113 



portion gradually declivent, humeral angles usually obtusely 

 rounded, not prominent (spined in perditor), front side margins 

 entire; scutellum reaching apical third of abdomen, gradually 

 narrowing from the base ; connexivum narrowly exposed ; 

 mesosternum finely carinate ; osteolar canal long, narrowing 

 and continued as a ridge to outer front angle of its supporting 

 plate ; tibiae above almost flattened or feebly sulcate. 



Twelve species are known from the United States, eight of 

 which occur east of the Mississippi. They are all greenish or 

 greenish-yellow in hue and very much alike in structure, their 

 separation therefore very difficult. 



KEY TO EASTERN" SPECIES OF THYAXTA. 



a. Third joint of antennae not longer than second; ventrals, except in 



rugulosa) with a black dot near spiracles and a black point on 

 incisures. 



b. Second joint of antennae equal to or but little longer than third; 



length, 8 or more mm. 

 '•. Front side margins of pronotum broadly concave; humeral an- 

 gles produced outward and slightly forward as acute spines. 



71. PERDITOR. 

 '•'•. Front side margins straight or nearly so; humeral angles round- 

 ed or obtusely angulated, rarely (in custator) spinose. 

 <J. Scutellum more elongated apically, its tip distinctly surpass- 

 ing the inner apical angle of corium; form of body elongate 

 oval ; membrane of elytra uniform hyaline, rarely with a 

 few fuscous dots; pronotum with edge of front side mar- 

 gins reddish or yellow. 

 ''. Pronotum and scutellum evenly, densely confluently punc- 

 tate, with few or no transverse ruga? ; disk of pronotum 

 without black dots; larger, 11-12 mm. 72. custator. 



" . Pronotum and basal half of scutellum uneven, with numer- 

 ous transverse ruga? enclosing or surrounding rather 

 coarse punctures ; front portion of pronotum usually with 

 two small rounded black dots; length, 8-9 mm. 73. casta. 

 '/'/. Scutellum with apical third broader and less elongated, its 

 tip feebly surpassing the inner apical angle of corium; form 

 of body more broadly ovate; membrane of elytra with nu- 

 merous oblong black dots or dashes along the veins; prono- 

 tum with edge of side margins more or less blackish, the 

 front portion of its disk with two black dots near middle; 

 length, 9-10 mm. 

 /. Corium without whitish spots; antennae with fourth and 

 fifth joints wholly or in great part fuscous; pronotum 

 with front lateral margins always distinctly black, its 

 disk with a broad purplish band between the humeral an- 

 gles; connexivum wholly pale. 74. calceata. 



