TAXONOMIC STUDY OF MORDELLIDAE — RAY 299 



MORDELLISTENA SONORENSIS, new species 

 FiGUBE 18, f 



This species is most closely allied to funerea Champion (1891, p. 

 343) and may be separated from the latter member of the genus by 

 the bicolored antennae, the much shorter, distal segment of the maxil- 

 lary palpi, the longer antennae, the larger size, the oval form of the 

 body, and the emarginate anterior margin of the compound eye. 



Length: 2.4 mm.; including anal style, 3.2 mm. Form elongate, 

 narrow^, sides rounded, subovate, elytra broadest at base, distinctly 

 narrowing and rounded caudad. Derm piceous black, five distal seg- 

 ments of antennae and anterior and intermediate legs fuscous, basal 

 six segments of antennae and mouth parts flavocastaneous. Body 

 densely covered with fine, recumbent, yellowish-white pubescence, 

 except on castaneous parts, where it partakes of ground color. 



Antennae 1.5 mm. long, reaching to posterior coxae ; segments 3 and 

 4 very short, equal ; 5-10 each as long as' 3 and 4 together and dis- 

 tinctly broader; 11 distinctly longer than 10, sides and apex rounded, 

 broadest medially. Distal segment of maxillary palpi enlarged, with 

 form of a scalene triangle, lateral margin almost straight, corners, and 

 mesal and apical margins distinctly rounded, broadest premedially. 

 Eyes coarsely faceted, distinctly emarginate on anterior margins. 

 Prothorax four-tenths broader than long (0.7 by 0.5 mm.), sides and 

 apex rounded, basal angles obtuse, base arcuate, midbasal lobe short, 

 but rounded. Scutellum short, subtriangular, sides and apex rounded, 

 broader than long. Elytra tw^o and two-thirds times as long as broad 

 (1.9 by 0.7 mm.), broadest at base, sides distinctly rounded to apex, 

 curvature greatest on apical fourth, apices individually rounded. 

 Intermediate tarsi distinctly longer than their tibiae ; penultimate seg- 

 ment of anterior and intermediate tarsi simple, filiform. Posterior 

 tibiae with two oblique ridges, basal one extending entirely across 

 outer face, the other halfway; basitarsi with three, second segment 

 with two oblique ridges, each extending halfway across outer surface. 

 Tarsal claws with four teeth, distal one long, acute, two intermediate 

 ones short, their sides almost forming right angles, the proximal, sub- 

 basal one rudimentary (fig. 18, /). Only a single spur visible at apex 

 of posterior tibiae, one-half length of basitarsus. Anal style short, 

 fairly stout, but one-half longer than apical ventral segment (0.75 by 

 0.5 mm.), evenly attenuate to apex; apical ventral segment almost 

 twice length of penultimate one. 



Type locality. — Nainari, Sonora, Mexico. 



Type. — A unique male, U.S.N.M. No. 52940, collected on August 19. 

 1927, on grass in^ricefield (A. Dampf). 



