142 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



of much more delicate tissue, it probably having been made in confine- 

 ment. Termeyer speaks of cocoons of the Mygalidse of South America 

 ("Aranea avicularia") even greater than the above. They are three inches 

 long by one wide, and are placed in the fissures on trunks of trees. They 

 contain thousands of eggs. This extraordinary size of the cocoon had made 

 the inhabitants, who do not observe carefully, imagine that this 

 spider would take the cocoon of " the bombice moth, del Guyavo 

 (Janus, Linn.)," and, having destroyed or eaten the chrysalis, would place her 

 own eggs therein, and then artificially close the hole by which she had pene- 

 trated it. One of these cocoons weighs as much as six cocoons of the silk 

 worm before they are washed, and as much as three or four after having 

 been washed. 1 



In San Domingo, according to Palissot de Beauvois, Mygale blondii is 

 found in the fields, where it prepares a hole in which it awaits its prey. 

 It does not confine itself to this manner of providing its food, but issues 

 forth evening and morning, climbs up trees, and, penetrating into the nests 

 of small birds, sucks their eggs or the blood of their little ones. The 

 female's cocoon is the size of a pigeon egg. 2 



Walckenaer describes the cocoon of Mygale avicularia as composed of 

 three silken envelopes, of which the middle one is thinner, and 



. does not contain a silken padding. The female places her 

 avicularia . 



cocoon near her tubular dwelling, and watches it assiduously. 



M. Moreau de Joannes, as quoted by Baron Walckenaer, says that the 

 female of this species in Cayenne envelopes, in a cocoon of white silk, her 

 eggs, to the number of eighteen hundred or two thousand. He observes 

 that the red ants eat the little MygalidaB when they issue from the cocoon. 

 M. Guerin had in his collection a. cocoon of this Mygale which was covered 

 over with a multitude of very small parasitic Cynips. This cocoon was flat- 

 tened, rounded, and about three inches in diameter. It was opened in the 

 presence of Walckenaer, and the young spiders were found enclosed therein. 3 



Madame Merian, who first recorded a report that the Theraphosoida3 prey 

 upon small birds, must have observed the cocoon of these spiders, as it 

 seems to me. She indeed speaks of them as having their domicile in a 

 large round nest resembling the cocoon of a caterpillar ; but the plate to 

 which she refers is a fairly accurate figure of a female tarantula with a 

 large oval cocoon attached to her abdomen, in the way usual to Lycosids. 4 

 I have the opinion that the egg cocoon of the spider was mistaken by 

 Mademoiselle Merian or her informants for a "domicile." 



1 Communications Essex Institute, Vol. V., 18(5(5-67, page 01. " Researches and Experi- 

 ments upon Silk from Spiders and upon their Reproductions, by Raymond Maria de Ter- 

 meyer." Translated from the Italian, and revised by Burt G. Wilder. 



2 Walckenaer, Apteres, Vol. II., page 211. 3 Apteres, I., 218. 



4 Desertation sur la Generation et les Transformations des Insects de Surinam., Mariie 

 Sibillse Merian. A la Haye, MDCCXXVI. Fig. 18 and explication. 



