. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. ANCESTRAL SPIDERS AND THEIR HABITS. 455 Liphistius,' and for this reason assigns it to his own family of Liphis- tioidge. 2 Among the oldest fossil spiders, and probably the oldest in America, is Arthrolycosa antiqua, from the CoaJ measures of Illinois, described by Mr. Harger.* As the horizon in which this fossil was taken ^ ^^. is synchronous with that of the argillaceous slate of upper Soider Silesia in which Protolycosa was
. American spiders and their spinning work. A natural history of the orbweaving spiders of the United States, with special regard to their industry and habits. Spiders. ANCESTRAL SPIDERS AND THEIR HABITS. 455 Liphistius,' and for this reason assigns it to his own family of Liphis- tioidge. 2 Among the oldest fossil spiders, and probably the oldest in America, is Arthrolycosa antiqua, from the CoaJ measures of Illinois, described by Mr. Harger.* As the horizon in which this fossil was taken ^ ^^. is synchronous with that of the argillaceous slate of upper Soider Silesia in which Protolycosa was discovered, this American spi- der has the distinction of being one of the oldest as yet known to science. Its true determination is therefore a naatter of great impor- tance. The aranead has generally been recognized as a type of a new family, Arthrolycosidse, as first established by Mr. Harger. Professor Scudder placed the family at the beginning of the order Anthracomarti. The supposed forcipulate character of the mandibles was considered suffi- cient evidence to overcome the otherwise general resemblance' to the Ter- ritelariaj, but this characteristic now ap- pears to be without sufficient warrant. Professor Scudder* made a reexamina- tion of the type in 1884, and decided against the forcipulate character of the palps as described by Harger. More re- cently Prof, diaries E. Beecher has made a thorough study of the type specimen, after cleaning it and exposing the append- ages by removal of the superincumbent matrix. After noting the differences which the study of the specimens under these con- ditions developed, Professor Beecher con- cluded that on account of these important f,,,, sgi. possU spider Arthrolycosa antiqua. differences it seems necessary to exclude the genus from the order Anthracomarti.' The marked resemblance between tlie ancient Avicularidae and the fossil seemed to suggest that Arthrolycosa is entitled to a place in the suborder Tetrapneumones, among the
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectspiders, bookyear1889
