Superfamily Argiopoidea 



the spiders preferring the cool and shady places. The weDS are 

 never furnished with a retreat, but are often strengthened by 

 a sheeted hub or by a stabilimentum. Certain exotic species 

 are social, a large number of individuals living near together 

 and spinning their orbs on a common foundation. 



More than sixty species of Uloborus are known, but only 

 .our are found in the United States; most of the species inhabit 

 hot countries; this being true, it seems strange that our northern 

 species should prefer cool situations. 



The following are the best-known of our species: 



Uloborus americanus (U. a-mer-i-ca'nus). — The female is 



about one fifth inch in length. It varies greatly in colour and 



markings. The abdomen is slightly notched in front, is widest 



and highest at one third of its length from its base; and at this 







Fig. 237. ULOBORUS AMERICANUS 



j 



l. ^r w 



Fig. 238. 



ULOBORUS AMERICANUS 



VENTRAL ASPECT 



point, it bears a pair of humps. The posterior row of eyes is 

 strongly recurved. The tibiae of the fore legs bear a bunch of 

 hairs at the tip. 



The male is from one tenth to one eighth inch in length. 

 The humps of the abdomen are small or wanting; and the tibiae 

 of the fore legs lack the brushes of hairs characteristic of the 

 female. 



The species has been commonly known as Uloborus plumipes; 

 but it was first described under the specific name used here. 



This remarkable spider has been found throughout the 

 eastern United States from the Great Lakes to the Gulf of Mexico, 

 and it probably occurs over the entire extent of our country; it 

 is also found in Europe. 



Although so widely distributed, it is found, so far as I have 



264 



