220 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Sbr. 



broad in front; abdomen slightly depressed, twice as long as wide. Legs 

 quite long, no spines under tibia or metatarsus I, one under tibia II, three 

 under metatarsus II; posterior pairs numerously spined; scopulas very thin 

 and scanty. Tibia of & palpus about as long as broad, with a large, stout 

 projection at outer tip; tarsus short, the bulb large, but little modified and 

 with a short, stout black tube at the tip. The ? resembles the $ ; abdomen 

 broader, no horny spot at base, and no spine under tibia II. The epigynum 

 shows a triangular opening with the corners rounded, and behind two round 

 dark marks. 



A male from La Chuparosa and the female from San 

 Jose del Cabo. Readily separated from P. directa by shape 

 of $ palpus and less spiny anterior legs. 



46. Prosthesima indecisa, sp. no v. 



Plate XIII, Fig. 20. 



Length 7 mm. Cephalothorax, legs, mandibles, and sternum yellow- 

 brown; abdomen dark gray, paler below, with a triangular horny shield at 

 base. The cephalothorax is considerably narrowed in front; the posterior 

 eye-row straight; P. M. E. round, less than their diameter apart, about that 

 distance from the equal P. S. E.; A. M. E. about their diameter apart, much 

 closer to the rather larger A. S. E. ; sternum but little longer than broad, sides 

 rounded. Legs short, no spines under the anterior tibiae, one under meta- 

 tarsus II, many on the posterior legs; coxae of first legs considerably longer 

 than the others. Abdomen once and two-thirds as long as broad, truncate at 

 base. The $ palpus has the tibia about as broad as long, with a straight, 

 stout projection at outer tip; the bulb is quite large and shows a curved tube 

 at the tip. 



One male from San Miguel de Horcasitas. 



47. Megamyrmecion calif or nicum Sim. 

 Plate XIII, Fig. 25. 



Several specimens from Sierra San Lazaro, Sept., and 

 from La Chuparosa. 



48. Cesonia trivittata, sp. nov. 



Plate XIII, Fig. 23. 



Length 5 mm. Cephalothorax pale yellowish, with a black stripe each 

 side, and a black seam; legs, sternum, and mandibles pale yellowish; abdo- 

 men whitish, with three black stripes above, one on each side reaching to the 

 spinnerets, and one in the middle usually ending before the tip, but in one 

 young specimen connected at tip with the side stripes; venter with two indis- 

 tinct dark stripes. Cephalothorax slender; posterior eye-row about straight; 



