2'76 proceedings of the academy of [1883. 



November 27. 

 The President, Dr. Leidy. in the chair. 

 Forty-two persons present. 



Note on Two New California Spiders and their Nests. — Rev. 

 Dr, McCooic presented a small collection of spiders received from 

 Mr. W. (j. Wright, San Bernardino, Cal., mailed November 18. 

 One of these came within a nest, and is a Saltigrade spider, 

 probably an Attus. The nest is a rare one, and was so happily 

 placed, by the builder, on a branch of sagebrush {Ephedra 

 antisyphillitica\ that it was preserved intact. It is the only one 

 which Mr. Wright had seen in site. Another nest, which he 

 had no doubt was the same, he had observed torn from its place 

 b^'^ some bird, as material for the construction of a bird's-nest. 



Nests somewhat similar arc habitually made by Pennsylvania 

 Saltigrades upon or among leaves which shrink up as they die 

 and tear the spinning work so as to destroy the specimen. The 

 one exhibited was in perfect condition. It is the tent and egg-nest 

 of the species which was alive within it, and the speaker thought 

 to be new. It is a large example, five-eighths inch in body-length, 

 stout, the legs of moderate thickness, the whole animal covered 

 closely with grayish white hairs, the skin beneath being black. 

 Dr. McCook named the species, provisionally, Attus opifex., with 

 a double reference to the discoverer (Mr. Wright) and the admir- 

 able hous.ewright qualities of the aranead herself. The nest is 

 externally an egg-shaped mass of white spinning-work, three 

 inches long by two and one-half inches wide. The outer part con- 

 sists of a mass of fine silken lines crossing in all directions and 

 lashed to the twigs within which it is enclosed. This maze sur- 

 rounds a sac or cell of thickly-woven sheeted silk, irregularly 

 oval in shape, two inches long by one inch wide, and also attached 

 to the surroi^nding twigs. At the bottom this cell or tent is 

 pierced b}^ a circular opening which serves the spider as the door 

 of her domicile. It is the habit of her genus to live and hibernate 

 within such a silken nest. Against one side of the tent within 

 is spun a lenticular cocoon (double convex) of thick white silk, 

 within which the eggs were placed. The young spiders when 

 received had escaped from the cocoon, and occupied the package- 

 box. They are about one-eighth inch long, resembling the mother, 

 but less heavily coated with gray. 



This collection also contained three specimens (9) of the 

 genus Pacetia, as defined by Thorell.^ This genus belongs to 



^ See "On European Spiders, Novae Acta Reg. Soci. Sci. Upsalensis," 

 vol. vii, ser. 3d, p. 196. 



