DIAPERESri NORTH OF MEXICO — TRIPLEHORN 435 



striae more finely punctured and not at all impressed, the prosternum 

 lacks tlie coarse punctures along the anterior margin and the elytra 

 are more convex and inflated basolaterally. 



S. aeneolum is strictly a boreal species. It has been taken from 

 under bark of Pinus ponderosa and Picea glauca. A series of 24 

 specimens from Duparquet, Quebec, was taken from lake drift by 

 G. Stace Smith from May 24 to June 27. Adults have been collected 

 in the field solely from May 15 (Plummer, Minn.) to September 30 

 (Cornwall, Conn.). 



Type. — AfCZ 4694. The specimen bears a light blue "Lake 

 Superior" label which was listed by LeConte as "Pic to Ft. William." 

 The LeConte collection contains three additional specimens with 

 identical labels and one specim.en with a yellow "Western States" 

 label. 



Specimens examined. — From the following localities, 118. 



United States: Alaska (Eagle). Connecticut (Cornwall). Illinois (Chicago). 

 Michigan (Detroit, Marquette). Minnesota (Plummer). New Hampshire 

 (Mount Washington). New York (Catskill Mts., DeBruce, Mount Maclntyre, 

 Oliverea, Redford, Saranac, Schenectady, West Point). Pennsylvania (Mount 

 Pocono). Wyoming (Grand Tetons, Jennj' Lake). 



Canada: Alberta (Edmonton). British Columbia (Cariboo District, Golden, 

 King Creek, McBride, Merritt). Labrador (Goose Bay). Manitoba (Aweme). 

 New Brunswick (River Glade). Ontario (Isle Royale, Michipicoten River). 

 Quebec (Cascapedia River, Duparquet, Kazubazua, Laniel). 



Genus Liodema Horn 



Liodema Horn, 1870 p. 385.— Bates, 1873b, p. 235. — Champion, 1886, p. 205. 



Type species. — Platydema laevis Haldeman (monobasic). 



Broadly oval, strongly and uniformly convex, moderately shining. 

 Head deeply inserted into thorax, concealing posterior margin of eyes; 

 clypeus large, well defined, rounded posteriorly, extending almost to 

 eyes; eyes large, deeply emarginate anteriorly, entire dorsal periph- 

 er}'^ sunken below surface level of head; antennae with segments 4 

 to 10 more or less serrate along inner margin. Pronotum smooth, ex- 

 tremely minutely punctulate, narrowly embracing humeral angles 

 of elytra at base. Elytra smooth, striae unimpressed, very minutely 

 punctulate, intervals flat, punctures sparse and visible only at high 

 magnification. Ventral surface moderately shining, finely and 

 sparsely punctured, metasternum entirely smooth laterally; epipleura 

 broad and concave at base, well defined and broadly continued to 

 apex of elytra; prosternal process broad between coxae, expanded 

 laterally to embrace coxae posteriorly, prolonged medially to the acute 

 apex; mesosternum forming prominent, apically rounded lobe which 

 extends forward, concealing prosternum in repose (pi. 3, fig. 14); 

 tibiae straight, moderately expanded apically, terminating in a comb- 



