THYCE AND POLYPHYLLA 321 



represent the female of riversi, as the coloration and hairy vestiture 

 are almost similar, but on consideration of the facts that the vesti- 

 ture of the female in all known instances is sparser than that of 

 the male and that in the female types of crinicollis the vestiture is 

 much closer than in the male types of riversi, it is almost certain 

 that the two cannot be specifically identical or even closely related. 

 The only species not included in the above table is the Plectrodes 

 palpalis of Horn; its characters, as derived from published state- 

 ments, are as follows: 



Thyce palpalis Horn (Plectrodes), Brownish above, piceous beneath, 

 moderately densely clothed with cinereous pubescence, short and re- 

 cumbent on the elytra, longer and semi-erect on the head and prothorax; 

 body beneath with long silken hairs, the abdomen with short recumbent 

 pubescence; clypeus very distinctly narrowed at base, the angles rounded, 

 the apical margin truncate and reflexed; prothorax broader than long, 

 narrowed in front, the sides moderately arcuate; surface coarsely and 

 moderately densely punctate; elytra densely punctulate, vaguely costate; 

 pygidium sparsely pubescent, as. on the elytra; legs fimbriate with moder- 

 ately long hair; middle tarsi distinctly longer than the tibiae; tarsal claws 

 unequally toothed throughout, especially the anterior; last joint of the 

 maxillary palpi oval, subacute at tip, three-fourths as long as the antennal 

 club, with deep entire excavation. Length 20 mm. California, Fuchs. 



Although this species probably belongs near fossiger of the above 

 table, the sparse vestiture of the pygidium and elytra and the failure 

 to note any depressed scale-like hairs among the erect hairs of the 

 pronotum, renders it impossible to identify it with any species 

 known to me. The locality may be widely different from that of 

 fossiger and allies. 



The fact that in certain females, as for instance that of harfordi, 

 the abdominal segments tend toward freedom, being rigidly con- 

 nate along the middle only, may cast a doubt upon the validity of 

 Plectrodes, where they are free in the male, as also probably in the 

 female. In all other features Plectrodes pubescens is a true Thyce, 

 and it is rather singular that no mention of Thyce was made by 

 Dr. Horn in defining his genus Plectrodes. 



In the type of angusticollis , the copulatory spicule is protruded; 

 it consists of two approximate similar vertical plates, rounded at 

 tip, convex on their outer surfaces and obliquely anteriorly hamate 

 beneath; the basal part, anterior to the inferiorly hamate dilated 

 apical part, is abruptly narrowed to a rather slender rod, where it 

 T. L. Casey, Mem. Col. V, Oct., 1914. 



