THYCE AND POLYPHYLLA 329 



preceding species, barely two-thirds as long as the tibiae. Length 

 27.5 mm.; width 13.3 mm. Arizona. A single specimen. 



proba n. sp. 



8 Last palpal joint differing distinctly from that of the three preceding 

 species, stouter, the outer surface not at all flattened but convex, with 

 an elongate-oval area of minute rugulosity from basal fourth to apical 

 third, its under surface with close-set and rather strong setigerous 

 punctures in more than apical half; body very much larger in size 

 and less convex, very stout, strongly shining, rather dark red-brown 

 in color, the sparse scaly vestiture yellowish-white; head large, the 

 punctures of the vertex not very coarse, rather shallow and close-set, 

 the large pointed scales dense except medially, the erect brown hairs 

 numerous; clypeus large, strongly narrowed at base, the angles acute 

 and obliquely very prominent, the apex broadly bisinuate; surface 

 concave, with coarse and shallow, not very close-set punctures, 

 bearing large elongate scales, which as usual become smaller and very 

 dense apically, the erect hairs short and few in number; antennal club 

 generally rather dark in color, three times as long as the stem; 

 prothorax almost exactly as in impigra throughout and similarly 

 clothed, except that the small inequality near the middle of each side 

 is more distinct, with its small condensed spot of scales more evident; 

 scutellum very different, broadly and densely squamose medially, 

 glabrous or nearly so thence to the sides; elytra two-fifths longer 

 than wide, oval, circularly rounded behind, a fourth wider than the 

 prothorax, the lines of sparsely aggregated scales well defined, the 

 sutural line dense, the first discal line of diffused scales notably broad 

 basally, the dense line of the suture extending outwardly along the 

 apical edge for a short distance, the scales everywhere only moderate 

 in size but broad, twice as long as wide; pygidium with similar scales, 

 rather dense basally and thence broadly along the middle and again 

 near the sides; abdomen in great part black, clothed as usual; first 

 tooth of the anterior tibiae smaller and feebler than usual , middle tarsi 

 distinctly shorter than the tibiae. Length 31.0-32.5 mm.; width 

 14.5-15.2 mm. Arizona. Two specimens diffusa n. sp. 



Last palpal joint long and very slender, but little over half as wide as 

 the penultimate, similarly convex externally but with the oval 

 chagrined area very much narrower than in diffusa; body smaller 

 and of much more abbreviated form, oblong-suboval, somewhat 

 inflated posteriorly, dark red-brown in color and shining; head, 

 clypeus and antennae nearly similar, except that the clypeus is 

 notably narrower and more parallel, the apex subtruncate to 

 broadly, feebly sinuate; prothorax and scutellum nearly similar 

 throughout; elytra scarcely one-third longer than wide behind the 

 middle two-fifths wider than the prothorax, the surface sculpture 

 nearly as in diffusa but differing greatly in having the second and 

 fourth lines of whitish scales very dense and conspicuous, the 

 second the narrower and generally exhibiting a greater tendency to 

 disintegrate; pygidium flatter, almost similarly squamose and with 

 very sparse stiff erect hairs, the scales broad, sparser near the sides; 



