OF WASHINGTON. 381 



LETTERS FROM THE SOUTHWEST. 



Insect fauna of Dasylirion wheeleri. 



By H. G. HUBBARD. 



HOOKER'S HOT SPRINGS, 

 GALIURO MTS., AR., May 25, 1897. 



The ridges in this vicinity are populated by numerous clumps 

 of Dasylirion wheeleri, many of them killed by the cattle, which 

 constantly eat out the buds. The young and vigorous plants do 

 not seem to be infested by insects, but the dead and dying plants 

 are inhabited by a fauna as interesting as that of the Giant Cac 

 tus, and among them I recognize a few species as identical, for 

 instance some of the small Histeridse and one of the Hololeptas 

 (ff. vicina}* which are extremely abundant in Dasylirion ; I find 

 also Trimiumpuncticolle, Eumicruslucanus, Ditoma gracilis, 

 and Holoparamecus pacificus. The numerous Staphylinid 

 beetles of the Dasylirion fauna are, however, wholly different 

 from those of the fermenting mass of Cereus giganteus, and be 

 long mostly to the more deplanate forms of the subfamilies Aleo- 

 charinae, Paederinae, and Piestinse. The large Belonuchus ephip- 

 piatus of the Giant Cactus is represented in Dasylirion by another 

 species (B. xanthomelas) , which, however, I find also in decom 

 posing Yucca and Agave. The large Dipterous (Volucella) larvae 

 and the Staphylinidae of the genus Maseochara as well as the 

 Hydrophilidae are here wanting, but there are in Dasylirion nu 

 merous other species of insects, almost all of them Coleoptera and 

 of small size. 



All these insects live between the broad, flat, imbricated, and 

 closely applied leaf bases of this most singularly constructed plant, 

 and are dependant upon the disorganization effected by a large 

 Calandrid beetle (Scyphophorus acupunctatus) , and, more 

 rarely, allied species {Yuccaborus frontalis). These beetles 

 usually enter the inside of the plant alongside the buds that start 

 between the leaf bases from the central axis. 



Into the holes made by these Calandrids the Hololepta and Be 

 lonuchus push their way, and they are accompanied by the smaller 

 ttistevi&s^Epierusplanulatus, Paromalusopunticz, P.gilensis, 

 P. tenellus], the smaller Staphylinidae, several Tenebrionidae 

 (Aphanotus parallelus, Ulosonia marginata), and finally a 

 very peculiar beetle, which is no doubt an undescribed Othnius. 

 The small Staphylinidae of this fauna are very interesting ; the com 

 monest is a Piestid, a veritable beauty (Piestus extimus Sharp). 

 It runs actively about and sweeps its long antennae from side to 

 side like a Lasmophlreus. Next in interest is a small slow-mov 

 ing Paederid {Leptogenius n. sp.), its body being dark umber- 

 brown, velvety and opaque, with dull-red head and legs. A few 



