104 KANSAS UNIVERSITY SCIENCE BULLETIN. 



shaped sacks, a little over three-eighths of an inch in di- 

 ameter and about one-fourth inch thick, of a texture like thin, 

 flabby, tissue paper. Of the two component valves, the one rest- 

 ing upon the web is flatter and smaller than the other, which is 

 more convex and has a sort of boxed edge. The suture at the 

 junction of the two valves is quite distinct. The eggs, about 

 100 in number, only partly fill the cocoon. They are whitish 

 and not agglutinate. In every case that came under my ob- 

 servation the mother spider was resting upon and clasping the 

 cocoon. 



Family DYSDERID.ffi. 



We have but three or four species of this family of spiders in 

 the United States, and these are not common. Members of the 

 genus Dysdera shut themselves up in a flattened, oval case to 

 deposit their eggs. This case is white, firm, and often covered 

 with sand or other extraneous matter. According to Simon, 

 the eggs are not enclosed in a special cocoon ; merely deposited 

 within the dwelling-sack occupied by the female. In the genus 

 Segestria, however, a lens-shaped cocoon of closely woven white 

 tissue is placed in a special incubation cell near the dwelling- 

 tube of the mother spider. As in the case of Dysdera, this cell 

 is usually covered with foreign material which adheres firmly 

 to it. The genus Ariadne, represented by A. bicolor, spins its co- 

 coon in a long dwelling-tube. After hatching, the young remain 

 with the mother a short time. 



Family FILISTATID^. 



Only a single genus, including two rare species, is found in 

 our country. Simon describes the cocoon as " flattened, floccu- 

 lent, and entangled in the midst of the web, like that of Amau- 

 robius." The cocoon of Filistata hibernalis, according to Hentz, 

 is spherical. 



Family LEPTONETID.ffi. 

 One genus, Usofila, is said to be represented in temperate 

 North America. The females of the foreign genus Ochyrocera 

 have, like Pholcus, the habit of carrying their eggs in their 

 chelicerse. These eggs are held together merely by a few 

 threads. 



