Superfamily Argiopoidea 



of the same colour. The male is nearly one eighth inch in length, 

 the female one sixth inch. 



This spider is remarkable on account of its social habits, 

 comparatively few social spiders being known. My attention 

 was first attracted to it on the University Campus at Baton Rouge, 

 La., where on various shrubs and trees there were unsightly masses 

 of dead leaves tied together with silk, and extending from them 

 a sheet resembling the sheet made by Agelena, but without a 

 funnel. The mass of leaves was found to serve as a retreat; and 

 in each retreat, there were several individuals of this species, 

 evidently the common owners of the retreat and the sheet-web. 



A closely allied species, Theridion eximius of South America, 

 lives in very large colonies, hundreds or even thousands of in- 

 dividuals uniting to form a common web. Simon states that they 

 sometimes cover an entire coffee tree; and F. O. P. Cambridge 

 says that he has seen their webs spun up to a height of fourteen 

 or fifteen feet amongst the foliage, being at the same time a yard 

 or more across. 



This is the Anelosimus (Adelosimus) studiosum of Banks's 

 Catalogue. 



Theridion dijjerens (T. dif'fe-rens). — We have three common 

 species of Theridion that agree in size, the female being about 

 one eighth inch in length, the male a little less, 

 and that resemble each other in having a distinct 

 dorsal band on the abdomen, which is brightly 

 coloured, often red or reddish in the middle and 

 white or yellow at the edges. These species 

 resemble each other so closely that they can 

 be distinguished with certainty only by an 

 examination of the palpus in the case of the 

 males and of the epigynum in the case of the 

 females. The specific differences were first 

 pointed out by Emerton who described the 

 three species. 



In the male of Theridion dijjerens the 



dorsal stripe is obscure and the whole abdomen 



dark reddish brown. The bulb of the palpus 



terminates in a projecting point which bears numerous teeth 



(Fig. 351); the terminal apophysis is of the form shown 



in the figure; and the embolus is of moderate length. The 



Fig. 35 1- 



THERIDION DIF- 



FERENS, PALPUS 



OF MALE 



352 



