432 Thos. H. Montgomery, 'Jr. 



Cocoonin? Habits 



The mating I have not observed, but it probably takes place 

 about the beginning of the year when the adult males are found 

 upon the webs of the females. Wild cocoons are to be discovered 

 as early as February. The cocooning season extends, at Austin, 

 from that month continuously into August. I conclude that it 

 usually terminates in August, for only eight cocoons were made 

 by my spiders after the eighth of that month; of these two were 

 made in September and one in October. Further the last cocoons 

 of a series, especially such dating from the middle of August, are 

 frequently infertile; compare on Table I the last cocoons of 2013, 

 2016, 2021 and 2031. Females live on after the cocooning season 

 provided they are well nourished. 



The completed cocoon is not quite globular but somewhat pyri- 

 form, the upper portion having a short stalk to attach it to the 

 object that overarches the web; when fresh it is snow white, when 

 older, yellowish, and its outer coat is markedly resistant and firm. 

 The process of cocooning and oviposition has much resemblance 

 to that of Theridium^ but Latrodectus is less specialized in that 

 she applies the thread mainly by direct application of the spinner- 

 ets and rarely by manipulation of the fourth leg pair. The case 

 as seen in the making of cocoon 2020E was as follows: At 5:37 

 p.m. the mother was seen working at the base, a disc of flossy silk 

 then only 2 mm. in diameter; she hung below it, holding its edges 

 with her three posterior pairs of legs while with her first pair she 

 suspended herself from the web; she was then making 52 appli- 

 cations of her spinnerets per minute. The base was completed 

 at 6:04, an inverted cup with a diameter equal to that of the fin- 

 ished cocoon. Oviposition, with rapidly repeated uplifts of the 

 abdomen against the concave surface of the base, lasted from 

 6:04 to 6:16. The construction of the cover of the cocoon occu- 

 pied from 6:16 to 8:19; for the first ten minutes the fourth pair 

 of legs were used to comb out the thread before each application 

 of the spinnerets to the cocoon, after that time these legs were no 



- Compare Montgomery: The oviposition, cocooning and hatching of an Aranead, Theridium tepi- 

 dariorum C. Koch. Biol. Bull., sii, 1906. 



