iQoS] Araneae Theraphosae of California 219 



the traps, certain ones came out at once, as if to learn the cause of 

 the disturbance. A Hve mosquito, presented by forceps to one 

 little spider, was savagely seized and carried into its tube. An 

 injured house-fly, placed near the burrow of another young spider 

 (5 mm. long, or less), was vainly tugged and pulled at for some 

 time. When noticed at the surface, with the trap raised just a 

 little and disturbed, they would commonly hold the door down 

 as do the adults. 



Not a few specimens were found to have a colony of minute 

 mites on the anterior slope of the abdomen above; the whole 

 colom^ of thirty or more, measuring little more than a milli- 

 meter across. Minute Collembolae are commonly found running 

 about in the nests. 



Aptostichus Simon. Actes Soc. Linn. Bord., 1892, p. 317. 



This genus, with its two described species, was made known 

 by Simon in his "Liste des Especes de la Famille des Aviculariides 

 qui habitent I'Amerique du Nord." I find no record of the 

 genus ha\-ing been collected or studied since; but Simon, in his 

 Histoire Naturelle (II, Supp., p. 901), adds a few male characters 

 not mentioned in the original diagnosis. The two species, as 

 given, are: 



A. atomarius California (Morrison) 



A clathratus . . California : Sta. Rosa del California (Geo. Marx) . 



I have collected, and have before me, two species which I 

 believe belong to this genus, and, indeed, seemingly differ from it 

 only in the character of the sternal impressions, which in one 

 species are of the type described for Eucteniza and Cyrtauchenius, 

 in the other nearer Amblyocarenum, not at all as in Stenoterom- 

 mata, as illustrated in the Histoire Naturelle (I, p. 102). As in 

 Eutychides versicolor, the smaller the individual, the relatively 

 smaller, less pronounced, and farther apart arc the sternal impres- 

 sions, both posterior and medial, — at least such is the case in the 

 new species described below. Still, altho Simon's type specimens 

 were presumably comparatively young individuals (14 and 15 

 mm. long, respectix'ely), I find in my specimens of the same 

 size, and smaller, no excuse for interpreting the sternal impres- 

 sions as being of the Stenoterommatan t^^pe, ascribed to Aptosti- 

 chus. The type of A. clathratus is in the U.S. National Museum, 

 at Washington, and Mr. Nathan Banks has recently examined the 

 specimen, at my request. He writes, "The sternum shows no 



