Superfamily Argiopoidea 



head-region, where there is also a central 

 pale stripe (Fig. 725). They live in damp 

 fields and in the vicinity of water, upon 

 which they run freely, and beneath which 

 they dive when alarmed. The egg-sacs are 

 white and spherical; the seam between the 

 two valves is less marked than on the 

 egg-sacs of Pardosa. The females drag 

 the egg-sacs after them attached to their 

 spinnerets, though when they are at rest 

 they often hold them in their chelic- 

 erae. 



The better-known species that occur 

 in our fauna are separated by Chamberlin as follows: 



Fig. 725. 



CEPHALOTHORAX OF 



PIRATA 



KEY TO SPECIES OF PIRATA 



A. Lower margin of the furrow of the chelicerae armed with 



but two teeth. 



B. Cephalothorax less than one twelfth inch in length. 



P. 643. P. minutus 



BB. Cephalothorax one eighth inch or more in length. P. 644. 



P. marxi 



AA. Lower margin of the furrow of the cheliceras armed with 



three teeth. 



B. Cephalothorax with no submarginal light stripes in the 



integument. P. 644. P. montanus 



BB. Cephalothorax with submarginal light stripes. 



C. Cephalothorax less than one twelfth inch in length, 



or at most not longer. 



D. All joints of legs except tarsi distinctly ringed 



with black (female). P. 643. P. aspirans 



DD. Femora dark at distal ends, other joints of legs 



light, not at all marked with dark. P. 644. 



P. humicolus 



CC. Cephalothorax much more than one twelfth inch in 



length. 



D. Cephalothorax in life or when dry showing on each 



side a marginal stripe of bright white hair. 



E. A black marginal stripe below each pale lateral 



stripe. P. 645. P. piraticus utabensis 



642 



