136 FAMILY V. — PENTATOMID^E. 



b. Humeri broad, subtriangular, their tips obtusely angled ; under 



surface yellow. (Carolinian fauna.) 88. tristigmus. 



bb. Humeri narrower, more inclined upward and backward, their tips 



acute angled or spinose; under surface dull white. (Austro- 



riparian fauna.) 88b. pyrrhocerus. 



The typical race tristigmus (Say), is the one described above. 

 In his original description Say mentions the antennae as being 

 "rufous, the fourth and fifth joints brown except the base of 

 fourth ; thorax with lateral angles rather prominent, angulated, 

 but not spiniform." The other two races are briefly treated 

 below. 



88a ( — ). Euschistus tristigmus luridus Dallas, 1851, 207. 



Form, especially in males, broader and less tapering behind the 

 humeri than in tristigmus. Color much as there, the antennae differ- 

 ing as stated in key; apical fifth of scutellum distinctly more sparsely 

 punctate, in great part smooth and white; membrane with fuscous spots 

 more distinct; pale spot at middle of each connexival segment larger, 

 usually reaching the margin, in tristigmus rounded and wholly enclosed 

 by fuscous. Humeral projections broader, with concavity in front more 

 pronounced, their tips not angulated but rounded. Length, 10 — 12 mm.; 

 width, 7 — 7.5 mm. 



Porter, Starke and Kosciusko counties, Ind., June 15 — 26. 

 Beaten from scrub oak and other foliage. Sherborn, Mass., 

 Oct. 25 (Frost) . This is the form occurring in the Transitional 

 Life Zone. The types of Dallas were from Trenton Falls, N. Y„ 

 and Nova Scotia. It was placed by Uhler (1861, 23) as a 

 synonym of tristigmus. Malloch (1919, 192) states that he is 

 "of the opinion that luridus is distinct from tristigmus. The 

 regularly rounded humeri of luridus are very conspicuously 

 different from the angular ones of tristigmus, and with the 

 naked eye it is possible to recognize the forms very readily." 

 He states that luridus occurs in northern Illinois and that speci- 

 mens are in the Urbana collection from Buffalo, N. Y. ; Omaha, 

 Nebr. ; Duluth, Minn., and Lone Rock, Wis. I cannot agree 

 with Malloch that luridus is a distinct species, as large series 

 show that it merges gradually into tristigmus. In my opinion it 

 is best designated as a race or variety worthy of a trinomial 

 name, whose range, roughly stated, extends from Nova Scotia 

 westward, north of latitude 41 degrees. It is probably the form 

 that Van Duzee (1894, 171) mentions as "abundant every- 

 where in trees, bushes and coarse weeds from May to Septem- 

 ber," about Buffalo, N. Y. 



