138 proceedings of the academy of [1884. 



May 13. 



The President, Dr. Leidy, in the chair. 

 Fifteen persons present. 



How Lycosa fabricates her Round Cocoon. — Dr. H. C. McCooK. 

 said that while walking in the suburbs of Philadelphia lately, he 

 found under a stone a female Lycosa (probably L. riparia 

 Hentz), which he placed in a jar partly filled with dry earth. 

 For two days the spider remained on the surface of the soil, 

 nearly inactive. The earth was then moistened, whereupon (May 

 2) she immediately began to dig, continuing until she had made 

 a cavity about one inch in depth and height. The top was then 

 carefully covered over with a tolerably closely woven sheet of 

 white spinning work, so that the spider was entirely shut in. 

 This cavity was made against the glass side of the jar, and the 

 movements of the inmate were thus exposed to view. Shortly 

 after the cave was covered, the spider was seen working upon a 

 circular cushion of beautiful white silk, about three-fourths of an 

 inch in diameter, which was spun upwards in a nearly perpen- 

 dicular position against the earthen wall of the cave. The 

 cushion looked so much like the cocoon of the common tube- 

 weaver, Agalena ntevia, and the whole operations of the Lycosa 

 were so like those of that species when cocooning, that the 

 speaker was momentarily possessed with the thought that he had 

 mistaken the creature's identity altogether, and again examined 

 her carefully, only to be assured that she was indeed a Lycosa. 

 After an absence of half an hour. Dr. McCook returned to find 

 that in the interval the spider had oviposited against the central 

 part of the silken cushion and was then engaged in enclosing the 

 hemispherical egg-mass with a silken envelope. The mode of 

 spinning was as follows : the feet clasped the circumference of 

 the cushion, and the body of the animal was slowly revolved ; the 

 abdomen — now greatly reduced in size by the extrusion of the 

 eggs — was lifted up, thus drawing out short loops of silk from 

 the expanded spinnerets, which, when the abdomen was dropped 

 again, contracted and left a flossy curl of silk at the point of 

 attachment. The abdomen was also swayed back and forwards, 

 the filaments from the spinnerets following the motion as the 

 spider turned, and thus an even thickness of silk was laid upon 

 the eggs. The same behavior marked the spinning of the 

 silken button or cushion, in the middle of which the eggs had 

 been deposited. 



At this stage, Dr. McCook left for an evening engagement, with 

 his ideas as to the cocooning habits of Lycosa very much con- 

 fused, indeed, by an observation so opposed to the universal 



