430 ARACHNIDA 



P. alarms (Hentz) (Fig. 677). Length 3 mm.; cephalothorax light 

 yellowish, with a black line on each edge; abdomen covered with irides- 

 cent scales which change in color from grayish-green to pink : a very active 

 spider living among stones on the ground. 



3. CASTIANEIRA Keyserling. Cervical groove pres- 

 ent; anterior median eyes not close to the margin of the 

 head; legs spiny: about 18 American species. 



C. descripta (Hentz) (C. crocata Emerton). Length 

 8 mm.; body black, with a bright red spot on the end of 

 the abdomen; ends of legs yellow: among stones in dry, 

 open places; its egg case is a small parchment-like disc 

 attached to a rock. 



4. MICARIA Westring. Body covered with scale-like 

 hairs; last segment of the hind spinnerets very short, 

 frequently indistinct, with an oblique groove; no cervical 

 groove: 13 American species. 



M. aurata (Hentz). Body resembles an ant in size 

 an d color; length 6 mm.; color light brown, varying to 

 bright yellow and orange: eastern states. 



5. TRACHELAS Koch. Posterior row of eyes curved forward ; legs with- 

 out or with few spines, dorsal groove present: about 5 American species. 

 T. tranquilla Hentz (T. ruber Keyserling). Length 8 mm.; cephalo- 

 thorax wide; abdomen ovoid; color deep orange brown, the abdomen 

 much lighter than the cephalothorax: under stones and leaves. 



FAMILY 12. AGELENIDAE. 



The funnel-web spiders. Cephalothorax large, and often narrow in 

 front and broad behind; cervical groove present; hind spinnerets very 

 long and 2-jointed ; mandibles large ; 3 terminal claws on the feet : mostly 

 large spiders which make a flat web on the grass and in the corners in 

 barns and cellars, in the middle of which is a funnel-shaped tube form- 

 ing the spider's retreat; about 50 American species. 

 Key to the genera of Agelenidae here described : 

 Oj Spinnerets not in a transverse line. 



&! Both rows of eyes strongly curved backward 1. AQELENA 



6, Both rows of eyes not or but slightly curved backward. 



Cj Anterior median eyes much smaller than the lateral 2. CORAS 



Cj Anterior median eyes either equal in size or smaller than the lateral. 



3. TEGENABIA 

 a, Spinnerets in a straight or curved line 4. HAHNIA 



1. AGELENA Walckenaer. Both rows of eyes strongly curved back- 

 wards so that the anterior median and the posterior lateral are in a 

 straight line; terminal segment of the hind spinnerets at least as long 

 as the basal segment: about 4 American species. 



