384 PROCEEDINGS OF THE ACADEMY OF [1887. 



wide, and are placed iu the fissures on the trunks of trees. They 

 coiitaiii 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 penetrated it. One of these cocoons weighs 

 as much as six cocoons of the silk worm when they are washed, and 

 as much as three or four after having been washed.' 



Madam Merian, who first recorded a report that the Theraphosoidse 

 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 waj^ usual to Lycosids.^ I have the opinion that 

 the e^g cocoon of the spider was mistaken by Madamoiselle Merian 

 or her informants for a "domicile." At all events we may consider 

 that it is fairly well assured that, iu her cocooning habits, the female 

 tarantula throughout most or perhaps all species, closely resembles 

 the Lycosoidse, and the resemblance probably extends to all the 

 Territelariie. In other words, the Theraphosid cocoon is (1) 

 round or ovoid, (2) is carried about with the mother, attached to 

 her body, or kept under her care, and (3) the young for a period 

 longer or shorter remain with their mother. The affinity between 

 these two great groups of araneads is also marked in their nesting 

 habits; both burrow in the ground a cylindrical tunnel or shaft 

 within which they domicile, sometimes lining it more or less com- 

 pletely with silk.^ 



7. Attitude at rest and in attack. While resting upon its silken 

 rug a favorite position of the tarantula was as follows: On one side 

 the first leg and the last leg were well extended, the feet were lifted 

 a little distance above the ground. The second and third feet were 



1 Communications Essex Institute, Vol. v., 1866 ^67, p. 61. "Researches and 

 Experiments upon silk from Spiders and upon their reproductions, by Raymond 

 Miria de Termcyer." Translated from the Italian, and revised by Burt G. 



Wilder. 



Di'sertation sur la Generation et les Transformations des insects de Surinam. 

 Mariae Sibillae Merian. Ala Hoye, nidocxxvi.; Fit^. 18 and explication. 



' I purpose tracing this resemblance more in detail in a subsequent paper on 

 "Nesting Habits of the American Purseweb Spider, Atypus niger." 



