CYDNIDAE OF THE WESTERN HEMISPHERE FROESCHNER 355 



Genus Sehirus Amyot and Serville 



Sehirus Amyot and Serville, 1843, p. 96. 

 Tritomegas Amyot and Serville, 1843, p. 98. 

 Canthophorus Mulsant and Rey, 1866, p. 344. 

 Adomerus Mulsant and Rey, 1866, p. 356. 

 Lalervis Signoret, 1881a, p. 656. 



Pending the completion of the author's studies of the Cydnidae 

 of the Eastern Hemisphere, the conclusions of China (1943) concerning 

 this genus are here accepted without question. The decision to do 

 this was a practical solution to a very complex problem which would 

 have involved review of a very extensive literature on a genus whose 

 main area of distribution is removed from the geographic region under 

 consideration. 



Diagnosis. — Among the genera of the Western Hemisphere this 

 genus may be recognized by any of many features: i.e., weakly com- 

 pressed anterior tibia which is almost square in cross section; lack 

 of distinct prosternal carinae; creamy white lateral margins to prono- 

 tum, corium, and abdomen; the scimitar-shaped terminal process 

 of the osteolar peritreme; and others. 



Description. — This description is based primarily on the New 

 World forms, but it is modified to encompass all Old World forms 

 available. The Eastern Hemisphere species at hand during this 

 study included bicolor Linnaeus, biguttatus Linnaeus, duhius Scopoli, 

 luctuosus Mulsant and Rey, sexmaculatus Rambur, and one unidenti- 

 fied Oriental species. 



Size small to moderate; oval, widest behind middle; dorsum moder- 

 ately convex, venter more strongly so. 



Head: Length usually more than three-fourths of width, eyes 

 projecting by half or more of their width; juga equal to or longer than 

 clypeus, sometimes convergent or contiguous beyond clypeus; surface 

 convex or concave, margins narrowly to broadly reflexed, closely 

 and coarsely punctured over most of surface; ocelli present, small, 

 situated on or behind a line connecting hind margin of eyes; antennae 

 5-segmented, I shortest, IV subequal to or shorter than V, each 

 longer than H and III, latter subequal to or longer than II; bucculae 

 moderately to very high, nearly or quite reaching base of head, 

 evanescent or abruptly terminated posteriorly; labium reaching 

 between middle of hind coxae, I shortest, II longest. III longer than 

 IV, II slightly compressed but without a foliaceous semicircular lobe. 



Pronotum: Length not more than half of width, margin carinate, 

 sides convexly narrowed from base, without lateral submarginal 

 row of setigerous punctures; anterior margin slightly to moderately 

 deeply concave; transverse impression moderate to obsolete, marked 



