1887.] NATURAL SCIENCES OF PHILADELPHIA, 383 



of determining the egg cocoon made by this family, the Therapho- 

 soidffi. While cleaning out the box in which she had been sent I 

 observed a piece of spinning work within, which proved to be an 

 abandoned cocoon. It was muck flattened, but when inflated 

 showed a hollow sisheroid composed of thick silken cloth, somewhat 

 soiled on the outside, but within clean and white. It measured two 

 inches along the longer axis and 1 1 inch along the shorter one. It 

 was empty of young, whose first moults, however, were within the 

 cocoon, as were also a few unhatched eggs which are yellowish 

 spheres, two millimeters in diameter. Three small openings in 

 the case showed where the spiderliugs had escaped. Both cocoon 

 and eggs are shown natural size in the accompanying figure. 



(Fig. 6); _ ^ 



The interior of this cocoon was without any flossy lining or 

 padding, resembling thus the egg sacs of the Lycosoidse generally. 

 A curious flap overlapped the cocoon at one side, whose use I could 

 not conjecture, unless it may have served to attach the object to the 

 mother's body; or, perhaps, it was simply a remnant of material 

 which had remained after the eggs were rolled uj) within the silken 

 rug upon which they are probably deposited after the manner which 

 I have shown to exist in the genus Lycosa} 



The janitor who received the box containing this spider and 

 placed it in my room was at the time new in his position and did 

 not understand the importance of observing all the particulars in 

 the habits of living creatures sent to the Academy. He therefore 

 failed to make any notes, but told me when questioned that he 

 believed that the cocoon was attached to the lower part of the body 

 of the spider when it arrived. No doubt this is a correct observation, 

 and we may assume with some degree of certainty that the large 

 egg sac of the Theraphosids is carried by the mother lashed to the 

 spinnerets at the apex of the abdomen, j^recisely as in the case of 

 Lycosids, whose well known habit is familiar to every frequenter of 

 our fields. 



This cocoon is exhibited in my collection of Aranead architecture 

 deposited in the Academy, and is the only one, so far as I have been 

 able to learn, exhibited in any similar institution. Termeyer speaks 

 of cocoons of the Mygalida3 of South America Q'Aranea avicularia") 

 even greater than the above. They are three inches long by one 



1 See Proceedings Academy Natural Sciences of Philadelphia, 1884. Page 

 138, my note on "How Lycosa Fabricates Her Round Cocoon". 



