THYCE AND POLYPHYLLA 307 



Antennal club (cf ) smaller and straight, the last two joints of the funicle 

 never anteriorly prolonged; elytral vestiture uniform in distribution; 

 abdominal segments sometimes partially free in the female.. .Thyce 



4 Antennal club, palpi and tarsal claws nearly as in Thyce, the elytral 

 vestiture uniform in distribution, the habitus of the body very 

 similar to that of Thyce throughout; female not at hand. .Plectrodes 



Polyphylla ranges over nearly the entire northern hemisphere, 

 while the last three genera of the table are confined to the more 

 southern Pacific coast and Sonoran regions and differ among them- 

 selves in only one or two structural features, but these are so 

 radical in the nature of the antennal club of Dinacoma marginata 

 Csy., and in the structure of the abdomen in the male of Plectrodes 

 pubescens Horn,- that I do not think they can be united very 

 appropriately. The tooth on the posterior claw in these three 

 genera, instead of being slender and similar to that of the anterior 

 claw as in Polyphylla, is broad and more or less unequally bifid. 



Thyce Lee. 



This genus is peculiar to the fauna of the extreme southwestern 

 Sonoran regions, ascending along the Pacific coast at least to and 

 nearly throughout Oregon, but it is most abundant and diversified 

 in the coast regions of southern California. The species of Thyce 

 are of moderately large size and are stout and subcylindric in build, 

 the integuments clothed with more or less dense subsquamiform 

 pubescence, which, as before stated, generally differs greatly in 

 character in the two sexes. In fact sexual differences throughout 

 the body are unusually, though very variably, accentuated in this 

 genus and in some cases affect the entire habitus to such an extent 

 that it may be impossible to associate the female with its proper 

 male unless they are found together. In some species the male and 

 female are almost similar in general habitus, but in such species 

 as fossiger, harfordi and blaisdelli, they are very different and the 

 females sometimes afford more decisive criteria for specific dis- 

 tinction than do the males. Owing however to the much greater 

 rarity of the female and the entire absence of that sex in most of 

 the species now known, the following table is based primarily upon 

 the male alone, excepting only in the case of the large and distinct 

 crinicollis, though the female will be described wherever known: 



