1904.] NATURAL SCIENCES OF PHILADELPHIA. 263 



missing papers some mistakes will be found to have crept into the 

 identification of certain species. 



My thanks are due to the Academy of Natural Sciences of Phila- 

 delphia, and to Mr. Witmer Stone in particular, for the loan of all of 

 their type specimens; and especially to Mr. J. H. Emerton, who not only 

 loaned me a considerable number of specimens, but also by correspond- 

 ence aided me very materially in the question of the synonymy of cer- 

 tain species: thus he pointed out the identity of his Pardosa hrunnea, 

 albomaculata and montana with species described by Thorell; of my 

 Lycosa ocreata pidchra with his Pardosa hilineata, and of my Lycosa 

 stonei with the Lycosa ocreata of Hentz. 



In regard to the genera I have employed, I must candidly admit 

 that the delimitation of the genera was the most difficult part of the 

 whole study. Simon (lS98a) has withdrawn both Trochosa and Pirata 

 into Lycosa, wdiile I maintain their separateness, and this because these 

 two genera intergrade no more closely with Lycosa than does Pardosa, 

 so that if Pardosa is to be upheld, the others must likewise be. It is 

 a question of either making one large comprehensive genus, and for 

 purposes of description subdividing it into a number of subgenera, or 

 of recognizing as many genera. In either case the boundaries of the 

 groups, be they called subgenera or genera, are equally difficult to 

 define. A new genus, Geolycosa, is proposed for forms which differ 

 from Lycosa by the length and thickness of the first pair of legs. Par- 

 dosa is composed of rapidly running, usually or always diurnal species, 

 of small size with great length of legs and large ocular area and small 

 chelicera; they are essentially Lycosids which have become diurnal 

 runners. Geolycosa is the very opposite, large forms with strong legs 

 and jaws fitted for digging the deep cylindrical holes in which they 

 live. Some of the species of Pirata are peculiar in forming small closed 

 nests in which they pass the winter, little cups of silks attached to the 

 under surface of stones. They are generally found close to water. 

 The species of Trochosa are nocturnal, living under stones, where they 

 apparently make no excavations. Sosippus, according to Simon, 

 builds a large web-sheeting. Aulonia has the habits of Pirata, and 

 is closely related to it. Lycosa is for the most part nocturnal, and 

 many of the species build shallow excavations lined with silk under 

 stones; others are, in the breeding season at least, diurnal, such as 

 scutulata and ocreata, and these are forms which approach Pardosa in 

 their structure. So we find that the structure corresponds pretty 

 closely to the habit: long legs in the diurnal species, high cephalic 

 region in the running and digging species, and low in the sedentary 



