234 APPENDIX F. ARACHNIDIANS. 



The second joint is the longest ; the third the smallest ; the fifth is, after 

 the second, the next in length ; then the fourth, and finally the sixth. 

 The external pair of fusi, or spinning apparatus, is slender, and as usual, 

 three-jointed ; the internal pair is very small, and not conspicuous. 

 The whole surface of the body and legs, above and below, is densely 

 covered with fine setose hairs. The color is uniform blackish brown. 



The Mygale hentzii is the large black spider known in the Southwest 

 as the tarantula, where its bite is greatly dreaded. 



A female specimen was collected on the 17 th of May, on an open, 

 barren prairie between Camps 2 and 3. Other specimens of both sexes 

 were taken on the 28th of June, near the head of south fork of Red 

 river. 



Plate XVI, fig. 1 represents Mygale hentzii seen from above. Fig. 

 2 is an underview to exhibit the lahrum (1), the maxillae (m), the 

 chelicerse (c), and the palpi (p), also to show the fusi (f). Fig. 3 rep- 

 resents the disposition of the ocelli. 



2. Lycosa pilosa, Girard. 



Zoology, PI. XVI, figs. 4 and 5. 



Spec. char. — Hairs of a yellowish brown color, covering the upper 

 parts. Beneath black ; cephalothorax subpyriform ; abdomen ovoid. 

 Palpi composed of five joints besides the maxillae ; terminal joint pro- 

 vided beneath with two small spines. ■ Legs very long and slender ; all 

 six-jointed. 



Description. — Of all the American Lycosa hitherto described the 

 present species is the one in which the legs are the longest and the 

 most slender. The size of the cephalothorax and abdomen is propor- 

 tionally smaller, however, than in L. fatifera, Hentz. 



The cephalothorax is longer than broad, elevated on its middle region, 

 and anteriorly very prominent ; subpyriform in its general outline ; the 

 narrowest part directed forwards. Its surface, when freed from its fur, 

 exhibits shallow grooves radiating from the centre towards the periphery, 

 pretty much in the same manner as in the Mygale just described, 

 although much less conspicuous. There is no central infundibulum, 

 which is replaced here by a minute longitudinal furrow about a tenth 

 of an inch in length. The abdomen is ovoid, and as usual, larger in 

 the female than in the male. 



The chelicerse are stout, with a very slight downwards inflexion, 

 provided with small protuberances upon the inner margin of its anterior 

 extremity, and terminated by a slender hook curved inwardly. The 



