56 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



was suspended by a loose band of darker colored coarser silk, seven milli- 

 metres long, and from the end of this band a few threads reached to the 

 bottom, twenty-seven millimetres, and sides of the vial. The abdomen of 

 the spider was reduced to the merest fragment, but the cephalothorax and 

 legs remained. May 25th the adult issued from one end of the cocoon. 

 The cocoon of P. dictyna^ mentioned above was about the same size and 

 had a smaller supporting band, but was composed of white silk, and was 

 much more delicate, nearly transparent.^ 



The beautiful Argiope argentata may be added to the list of spiders 

 whose cocoons are parasitized. Dr. A. Davidson sent me from Los Angeles, 



California, a fine large cocoon, which upon opening the box I 

 Parasite found to be occupied by a numerous brood of small black Ich- 

 ^^ p^ neumonids, which proved to be a species of Eui)elmus.'^ It is 

 coon 3^^ black, glossy, with a metallic lustre. The female is much 



larger and stouter than the male. These insects were domiciled 

 within the yellow floss which pads the interior of the cocoon, and liad 

 probably been reared from naked pupae, as no pupal cases were found. 

 Several dead pupte in at least two stages of development, a number of 

 infertile spider eggs, and a quantity of castings and disjecta membra of the 

 pupse were strung throughout the padding surrounding the central cavity 

 in which the Ichneumons were congregated. Among these interlopers, or 

 crawding upon the surrounding fibres, were a few (six or eight) living spi- 

 derlings, the feeble remainder of the original colony. Tliese as well as the 

 parasites were probably hatched en route from California in the mail bag. 

 Dr. Davidson took the spider cocoon on Catalina Island, California, where 

 the species is abundant. It spins its webs in cacti, and the cocoons are 



always placed some distance from and behind the snare (" around 

 Argen- ^j-j^ corner, as it were "), upon one of the plants to which the 



^ ^ °' foundation lines are attached. The cocoons are never hung upon 

 coon 



the orb as with the specimen spun for me in captivity, and de- 

 scribed Vol. II., page 84. The same gentleman remarks that the cocoons 

 so closely resemble in coloring the cactus as to make them almost difficult 

 to find ; and he thinks it an example of concealment by mimicry of colors. 

 However, cocoons of the species received from various parts of California 

 have the same general hues, yellow, with more or less green, ^ quite regard- 

 less of their situation. In the above case the "protective" resemblance did 

 not protect, as appeared from the vigorous brood of invading Ichneumonids. * 



' Howard : " The Hymenopterous Parasites of Spiders," Proceed. Entom. Soc, Washing- 

 ton, Vol. II., No. 3. 



^ Eupelmus piceus. Described by Mr. L. O. Howard. 



' See Examples, Vol. II., pi. iv. 



* Mr. Howard expresses the opinion, through a letter to I\Ir. E. T. Cressoii, that although 

 many species of Eupelmus are egg para.sites, still others are hyperparasitic ; and judging 

 from the size of the above species he thinks that it is probably a parasite upon some Pimpla 

 which was the primary parasite in the spider cocoon. 



