"i56 i>AVEXH()K'i' A(;ai)Kmv of natural sciences, 



eye prominence of medium size, black, furnished with a few spiny hairs of 

 which two in front are hmger than the others; eyes large, with the interval 

 between them less than their diameter. Bases of the falces furnished with 

 strong, inequal hairs ; fixed finger much .shorter than the base, teeth some- 

 what obtuse and blunt, commencing with two rather small teeth -, the first a 

 little larger than the .second, a third much larger, the fourth and fifth quite 

 small and situated on the anterior edge of the sixth, which is largest of all; 

 a seventh small, followed by a double row of three teeth each, the anterior 

 of medium size, and the posterior small. The movable finger with two 

 large teeth, the posterior largest, with two small teeth on its anterior border. 

 First ventral segment of the abdomen, with a rather deep and broad canal, 

 broadening out rapidly posteriori}', betw<»en two prominent smooth fulvous 

 plates, and containing two stigmata-like openings. Maxillary palpus with a 

 number of spin}- hairs on the inside near the extremitj^ of the femur, and 

 also on the inside of the tibia near its base; femur, tibia and metatarsus fur- 

 nished on the inner margin with numerous fine hairs— a less number out- 

 side. Metatarsus and tarsus of about the same length as the tibia, cylindri- 

 cal or slightly enlarged toward the extremity. Metatarsus of the third feet 

 with two dorsal rows of five spines each, and a row of three spines inside. 

 Metatarsus of second feet with a dorsal line of five and one of three spines, 

 that nearest the base shortest; also four spines on the inner margin. Tibiae 

 of the second and third feet, with one or more spines near the extremity. 



These specimens a^ree very closel}- with the description of the 

 female of D. formidabiliK of Eugene Simon. The main differences 

 are, formhJahilis is without a median stria, while this has a slight 

 but distinct stria; the posterior border of the cephalic shield 

 largely and obtusely truncated, while in this it is scarcely trun- 

 cated; the first ventral segment with a light longitudinal canal, 

 while m this the canal is very distinct, deep and broad, differ- 

 ing greatly in form from the figure given (PI. 3, figure 2(J £of Si- 

 mon?J); the teeth are rather more obtuse than in formidd hills: 

 but one row of dorsal spines are mentioned as occurring on the 

 second and third metatarsi oi formidahilis. while in this there are two 

 rows. Nevertheless, T question very much whether a comparison of 

 these specimens with the types oi /ormtdaJ/ifis would not show them 

 to be identical. The specimen from California is smaller and gen- 

 erally less fully developed than the Arizona specimen, except the 

 genital organs appear to be better developed. 



It is probable that the specimen collected by Capt. Marcy in 

 Northwest Texas, in 1853, and described b}' Girard, under the name 

 of froJeodcs snhiJiita Say, may be the .^ of this species. The origi- 

 nal specimen is now in the Museum of the Academy of Natural Sci- 

 ences of Philadelphia, though in bad condition. It is certainly quite 



