1888.] natural sciences of philadelphia. 425- 



December 11. 

 The President, Dr. Jog. Leidy, in the chair. 



Twenty-three persons j^resent. 



A paper entitled "Description of a New Species of Orithopristis 

 ffom the Galapagos Islands." By David S. Jordan and Burt 

 Fesler, was presented for publication. 



Double Cocooning in a Spider. — Dr. Henry C. McCook remarked 

 that spiders may be divided into two grouj)S in relation to their 

 cocooning habit. The individuals of one grou^) habitually spin 

 several cocoons. Those of the other group habitually spin but one. 

 The latter, however, are subject to some variation, the reasons for 

 which have not been satisfactorily explained. Epeira diademata 

 for example, habitually spins but one cocoon, and yet the Spanish 

 investigator Termeyer,^ in the early part of this century, discovered 

 and announced that she would spin as many as six cocoons when 

 specially nourished. The fact struck the speaker as an extraordinary 

 one, and he had never yet quite obtained consent to fully admit it. 



There are some facts, however, which have recently been uncovered 

 that show a tendency to a variation of habit in tliis line in one of 

 our familiar orb-weavers. Several years ago a clerical friend, the 

 Rev. Dr. P. L. Jones, had brought him two cocoons of Argiope 

 cophinarla ( Walck.)'^ Avhich had been spun on his premises by the 

 same spider. The fact seemed to him strange and interesting, and 

 he reported it. About a year ago, Mrs. Mary Treat brought to 

 Dr. ]\IcCook's notice the fact that she had discovered what appeared 

 to be a variety of Argiope cophinaria, which makes four cocoons, 

 and which she had accordingly named Argiope imdtichoncha.^ She 

 sent him a string of these cocoons of which there were four of the 

 usual shape and about the usual size, strung within a few inches of 

 each other. They wei'e spun on the wall of a kitchen in a house in 

 western Missouri. Mrs. Treat also sent the spider which spun the 

 cocoons. The specimen was very much dried up and in such a con- 

 dition that the speaker could not make a very satisflictory study of 

 it, but he found nothing in it differing in the least degree from 

 Argiope cophinaria. If it be the same species, what are the peculiar 

 circumstances that have caused such a remarkable variation in the 

 habit? or is it true that this species does, more frequently than has 

 been supposed, indulge herself in the luxury of an additional egg- 

 sac ? Two cocoons of this lot were opened and found to contain 

 young spiders that had hatched, but died within the egg-sac probably^ 



1 See Walckenaer's Apteres Vol. I, p. 152. 



^ Arg. ri/iai-iti (Hentz). 



3 American Naturalist, December 1S87, p. 1122. 



