DESCRIPTION OF NEW SPECIES 145 



Male. Usually smaller. Fifth antennal joint elongate, oblong- 

 triangular, broadly arcuate anteriorly, not noticeably wider than the fol- 

 lowing joints. Fifth ventral abdominal segment rather broadly sinuato- 

 truncate. 



Female. Usually larger. Fifth antennal joint shorter, more tri- 

 angular and more subangulate anteriorly ; all the joints rather less robust. 

 Fifth ventral broadly rounded at apex. Femora less stout and more 

 parallel. 



Measurements. Length (Types), 3-3.3 mm.; width, 1-1.2 mm. 



Holotype, male, in the collection of the California Academy of 

 Sciences ; allotype, female, and paratypes in that of the author. 



Type locality. Blood's Meadow, Alpine County, California; col- 

 lected by the author on July 14th, 1907, at an elevation of 7000 feet. 

 Beaten from the blossoms of a white Ceanothus, in company with Amphi- 

 chroum pallidum Casey and another species of Listrus which is referred 

 to montanus Casey. Dilutus is distinct in the similarity of the sexes, 

 short dark pubescence and inconspicuous maculation. In montanus the 

 pubescence and maculation are well developed, hairs rather long, form 

 different in the sexes and more oval, and besides the antennae are dis- 

 tinctly incrassate, the eleventh joint is shorter, more robust, oval and 

 wider than the preceding joints. 



Listrus martini, new species. Form somewhat elongate, more or less 

 oblong-ovate, distinctly more than twice as long as wide. Color black, 

 with a feeble purpureo-cupreous lustre, surface shining; mouth-parts 

 pale rufo-testaceous, last two joints of the maxillary palpi blackish ; first 

 joint of the antennae black, second rufo-testaceous, succeeding joints 

 similarly pale becoming gradually infuscate to tip; legs pale rufo- 

 testaceous, femora rarely slightly infuscate. 



Pubescence not dense, rather short and slender, more or less plumbeo- 

 cinereous, with broad fasciae of nigro-f uscous hairs arranged as follows : 

 A moderately wide transverse basal fascia, usually unbroken; post-basal 

 fascia absent ; a broad median fascia extending from margin to margin ; a 

 similar subapical fascia joining the median fascia along the suture; 

 apical maculae absent. The median and subapical fasciae may by diffu- 

 sion nearly coalesce, in such cases separated laterally by a narrow line of 

 pale hairs, rarely distal two-thirds of the elytra are nearly dark. Prono- 

 tal lateral vittae not distinct; median dark area oblong-oval, extending 

 from apical to basal margins, usually widest at middle and not con- 

 stricted as in the hourglass figure. Head slightly maculate in the central 

 area. 



Head rather broad and relatively short, muzzle small ; front broadly 

 and feebly convex, sometimes feebly impressed behind the epistoma, with 



