Agalenidce and Dysderidce. 189 



Phrurolithus alarius. 



Herpyllus alcmus Hentz. 



Plate VI, figures 5, 5a, 5&, 5(Z, 5/, 5^^, 5/;. 

 Full grown female 4'"'" long, cephalothorax 1.5'""\ PI. vi, fig. 5. 

 The cephalothorax is nearly as wide as long, rounded at the sides. 

 The head is about half as wide as the thorax and the eyes are close 

 together and all about the same distance apart, fig. 5a. The middle 

 eyes of the upper row are oval and turned obliquely, nearest together 

 towards the front. 



The abdomen is oval, widest behind, and a little flattened on top. 

 The legs are long and slender, except the tibi?e and metatarsi of the 

 first and second pairs which are twice as thick as the same joints of 

 the other legs, fig. 5. The legs are light yellow or white with gray 

 hairs, except the tibia and patella of the first pair, which are black 

 or dark gray with the tip of the tibia white. The tibia and patella 

 of the second pair are marked with lighter gray in the same way. 

 The tibia and metatarsus of the first and second pairs have two rows 

 of strong black spines on the under side, fig. bb. 



The cephalothorax is light yellowish with a black edge each side 

 and a few irregular radiating gray marks forming two indistinct 

 longitudinal stripes. The abdomen is gray with transverse white 

 markings which vary greatly in shape and size in diflrerent individuals, 

 figs. 5, 5a. The abdomen is covered with fiat branched hairs that 

 are iridescent, changing from light grayish-green to pink with the 

 motions of the spider, fig. 5d. The under side of the body is pale 

 with a dark mark in front of the spinnerets, and in some individuals 

 a few irregular marks along the sides. 



The male palpi are large. The femur is thickened on the under 

 side near the outer end, forming a short black pi'ocess covered with 

 short stiff hairs. The patella and tibia are both short. The tibia 

 has on the outer side a long process slightly curved downward that 

 extends along the side of the tarsus for half its length, fig. bg. The 

 palpal organ is so long that its base extends over the end of the 

 tarsus, fig. 5f. 



The epigynum has two lai'ge openings turned toward the sides a 

 little in front of the transverse fold, fig. 5h. 



It lives on and under stones in dry open ground and runs with 

 great swiftness short distances at a time. When still it lies close to 

 the stone with the tibiae drawn up over the back, as in fig. 5, the 

 thickened and colored legs of the first pair are then the parts of the 

 spider most easily seen. 



Massachusetts and Connecticut. 



Trans.. Conx. Acad., Vol. VITI. 25 Jan., 1890. 



