AEAGHNIDES— AltANElDES— KETITELARIiE. 73 



a break in the stone there is no trace of a pedicel, was found by me in the 

 shales at Green River, Wyoming. 



A single specimen (No. 8935), of an -egg-cocoon was also found at 

 Florissant, Colorado, having the same general appearance, but with no trace 

 of a pedicel and slightly larger than any of the others, being 6""° long and 

 4""" broad. It is of course impossible to say that it is the same species. 



Still another (No. 1.173) was brought by the Princeton expedition from 

 Florissant, differing in the opposite direction, being considerabl}' smaller 

 and so preserved as to appear broader than long. It is provided with a 

 pedicel 1.4""" long, but is itself only 2'""' long and 2..^°"" broad. 



Quesnel, Green River, Florissant. 



THERIDl UM Walckenaer. 



No less than sixteen fossil species of this genus have been described, 

 thirteen from amber, one from the beds of A\x, at about the same horizon, 

 and two from Oeningen. Those from Oeningen and Aix are very different 

 from tlie two here described, and those figured from amber are scarcely 

 nearer, though T. opertaneum bears some resemblance to T. granulatum, 

 and T. seclusuni to T. hirtuni. The vast majority of the numerous known 

 living species of this genus are from Europe, but not a few occur in our 

 country, especially in the Southern States, and one or two are reported from 

 other parts of the world. It is therefore almost exclusively a north temperate 

 genus, but is by no means confined to the warmer parts, and its occurrence 

 at Florissant has no special significance as to the climate of tlie times. 

 (November, 1881.) 



Table of the species of Tlieriiliiim. 



Large species; the cephalothorax much louger than broail ( 9 ) 1- ^- opertaneum. 



Small species; the cephalothorax nearly circular { ^ ) 2. T. seclusuni. 



1. Theridium opertaneum. 



PI. 11, Fig. 3(9). * 



Female. — Cephalothorax elongated, comparatively slender, nearly equal, 

 about twice as long as^broad. Legs slender, imperfectly preserved, not very 

 long, sparsely furnished with rather short delicate spines, not longer than 

 the width of the legs. Abdomen very large, nearly globular, nearly three 

 times as broad as the cephalothorax, of a greenish tinge, though the whole 

 body is brown. 



