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THE AMERICAN NATURALIST [Vol. XLII 



of growth that this species is able to reach full size in 

 one year. Males, accordingly, live for only a relatively 

 short time as adults, and their life time would seem to not 

 exceed one year. In my observations on Epeira mar- 

 morea I found on July 25 among 16 recognizable females 

 (in young of 8 mm. body length or less the sexes are ex- 

 ternally indistinguishable) only 5 adults, while on August 

 31 out of 24 females all but 3 were adult ; these data indi- 

 cate for this species that while at the beginning of the 

 summer few females are adults, at its end most are. It 

 is then probable for this species, though not proved, that 

 few females live over from one breeding season to another, 

 and then only under favoring environmental conditions, 

 a conclusion reached by McCook for Argiope. But the 

 females live at least some months longer than the males 

 for they are to be found later than the breeding season 

 and after all males have disappeared ; and there are cases 

 on record (cf. McCook) where females of certain species 

 have been kept from two to seven years. I have de- 

 scribed for Lat ro(/e<t)(.s ] " how the mating occurs in the 

 late winter at Austin, Texas, the adult males are not 

 found after this season, while the females continue to 

 produce cocoons until the following autumn. We might 

 say in general that males of spiders probably do not live 

 longer than one year, females some months longer or 

 in certain cases several years. 



5. The Cocoontxg of Loxoscklks m* fkscens Duf 

 I give these brief notes here because the cocooning of 

 no sicariid has been hitherto described, and because it 

 may be of some interest from the standpoint of com- 

 parative architecture. The cocoon of Loxosceles is ses- 

 sile, attached to the snare, so resembling that of Sicarius, 

 while in Scytodes, the only other genus of the Sicariidae 

 for which the cocoon has been described, it is carried in 

 the ehelieera of the mother. 13 



