24 CALIFORNIA ACADEMY OF SCIENCES. 



very distinctly, wider than long in the former. It is true 

 that the sexes in these cases are different, but on examining 

 a full series of a closely-allied species — relrusa — described 

 below, it is readily seen that the sexual differences in the 

 general form of the body, even of the head, are almost ab- 

 solutely inappreciable; it is in fact a forcible instance of 

 what Dr. LeConte (Trans. Am. Ent. Soc. YI, p. 213) calls 

 the polarity and, it might be added, concentration of sexual 

 characters. Here we have the sexual modifications at the 

 abdominal vertex extremely well marked, elsewhere, how- 

 ever, if we except a slightly longer second antennal joint in 

 the males, they are not at all apparent. 



19 — L. luctUOSa 1^- sp. — Form slender; bead, pronotum and abdomen 

 ^broiigbout black; elytra rufo-piceons, not paler at tip; legs dark brownisb- 

 flavate; antennae piceons, pale at tbe tip; pubescence almost absent anteriorly, 

 moderately sparse and fine on the elytra, somewhat dense on the abdomen; 

 integuments polished. Head moderate, distinctly longer than wide; base 

 truncate in the middle, angles rather narrowly rounded, sides parallel and 

 very feebly arcuate; vertex moderately produced, truncate at apex, feebly 

 arcuate in the middle; punctures feeble, small and rather sparse; median line 

 rather broad, equal throughout; antennas distinctly shorter than the head 

 and prothorax together; basal joint distinctly longer than the next two com- 

 bined, second slightly shorter than the third, sub-equal to the fourth. Pro- 

 thorax fully as long as w^ide, equal in width to the head; sides excessively 

 feeblj' convergent posteriorly throughout and very feebh" arcuate; base 

 broadly sub-truncate in the middle; apex broadlj', rather feebly and equally- 

 strougly arcuate; nuchal sinuation feeble, two-fifths as wide as the disk; 

 anterior angles rather narrowly rounded, basal broadly so; disk transversely, 

 evenly and moderat?ly convex, very feebly, finely and rather sparsely punc- 

 tate in the middle, more closely so at the sides: median impunctate area 

 moderate in width, even throughout, not impressed. Elytra at base slightly 

 wider than the prouotum: sides parallel and feebly arcuate; together 

 broadly, roundly and rather feebly sinuate behind; disk less than one-third 

 longer than the pronotum, one-fourth longer than wide, feebly and narrowly 

 impressed aloug the slightly elevated suture, finely, feebly, evenl}'-, sub- 

 asperately and rather spars -Ij'^ punctate. Abdomen slender, scarcely nar- 

 rower than the elytra; sides straight and parallel; surface minutely, very 

 densely, sub-asperately and evenly punctate. Legs rather slender; first joint 

 of the posterior tarsi oue-thirLl longer than the second, much shorter than 

 the fifth; anterior tarsi slightly dilated. Length 4.2 mm. 



San Francisco, 1 ? . 



