BEMBIDIIN/E 147 



rupted; but this condition properly should not be so described; the 

 anterior external impression is also observable in the preceding 

 group; it may be held, however, to presage the extreme develop- 

 ment seen in sulcatum. The elytral strife in Lopha are always 

 much abbreviated behind. Our species are rather numerous and 

 may be defined as follows: 



Elytra highly polished throughout 2 



Elytra with micro-reticulation, which is sometimes distinct under proper 



enlargement but often very feeble and apical only 10 



2 Punctures of the elytral striae small 3 



Punctures of the striae relatively coarse or strong, deep and more con- 

 spicuous 9 



3 Elytra each with an anterior post-humeral and posterior, external, 



pale spot 4 



Elytra each with but a single spot, post-humeral in position 6 



4 Elytra with the four spots well developed and always evident, the 

 posterior never obsolete so far as observed. Body moderately ven- 

 tricose, polished, black, rather convex; under surface black, the epi- 

 pleura piceous, the legs rufous; head scarcely to evidently narrower 

 than the prothorax; antennae as long as the elytra, thick, fuscous, 

 gradually testaceous basally, the medial joints twice as long as wide; 

 prothorax two-fifths or slightly more wider than long; base three- 

 fifths the maximum width; sides strongly rounded anteriorly as 

 usual; foveae smooth, small, deep; fine impression along the basal 

 bead with a series of moderate punctures, more or less obsolete at 

 the middle; elytra oblong-oval, one-half longer than wide, two-fifths 

 to half wider than the prothorax; striae unimpressed, the punctures 

 fine, well separated, obsolete from slightly behind the middle; foveae 

 near basal fourth and apical third. Length (a 71 9 ) 2.6-3.4 rnm.; 

 width 0.8-1.2 mm. Rhode Island to Colorado (Boulder Co.). 

 Generally somewhat abundant. [Bemb. oppositum Say] 



quadrimaculatum Linn. 

 Elytra with the anterior spots always distinct, the posterior very small 



or faint and frequently wholly invisible 5 



5 Body notably elongate, convex, polished, black, usually with faint 

 bronze lustre, the post-humeral spots extending inward to about the 

 middle of each elytron, the posterior spots small and faint, though 

 generally traceable; under surface black, the legs blackish- piceous; 

 head fully four-fifths as wide as the prothorax and wider than an 

 elytron, the eyes well developed; antennae thick, black throughout, 

 four-fifths as long as the elytra, the medial joints not quite twice as 

 long as wide; prothorax two-fifths wider than long, widest near an- 

 terior third; base three-fifths the maximum width; sides anteriorly 

 strongly rounded; line of punctures before the basal bead confused, 

 moderately coarse; foveae smooth, not very small, oval and deep; 

 elytra unusually elongate, three-fifths longer than wide, two-fifths 

 wider than the prothorax, oblong-oval in form; striae scarcely im- 

 pressed, obsolete in apical third, the seventh a row of feeble punctures 



