ARANEAE 



421 



Fig. 661 



Steatoda borealis 

 (Comstock). 



pair; the 2 mandibles straight and parallel to each other: the web con- 

 sists of a flat net held in place by numerous threads; 4 American species. 

 S. borealis (Hentz) (Fig. 661). Body about 6 mm. long and reddish- 

 brown in color, the abdomen usually with a light 

 stripe running around the front half and one in the 

 middle: among stones or in fence corners; common. 

 2. LATHRODECTUS Walckenaer. Abdomen round 

 and hairy ; side eyes widely separated : 2 American 

 species. 



L. mactans (Fabricius) (Fig. 662). Body 12 

 mm. long and black, with a bright-red, hourglass- 

 shaped spot underneath, and one or more red spots 

 over the spinnerets and sometimes along the middle 

 of the back; abdomen of male ovoid, with a row 

 of red and white spots in the middle line and 4 



pairs of red and white stripes on the sides: 

 common; web large, with a funnel-shaped retreat 

 in the middle. 



3. ARGYRODES Simon. Abdomen with a 

 high pointed hump: about 13 American species. 



A. trigonum (Hentz) (Fig. 663). Body yel- 

 low, triangular in shape, 3 mm. long and 3 mm. 

 high in the female; male with 2 horns in front 

 of eyes: common; web between branches or 

 leaves, or among the supporting strands of the 

 webs of larger spiders. 



4. SPINTHARUS Hentz. Labium and sternum 

 united; abdomen tapering to a blunt point over 

 the spinnerets; side eyes close together: 1 

 American species. 



S. flavidus Hentz. Body 4 mm. long; 

 cephalothorax circular; upper surface of abdo- 

 men flat with a white stripe on each side and 

 red and black in the middle: found on low 

 plants; web unknown. 



5. THERIDULA Emerton. Anterior row of 

 eyes curved; first legs much longer than the 

 fourth: 2 American species. 



T. sphaerula (Hentz). Body 2.5 mm. long; cephalothorax yellow or 

 orange with a median black stripe; abdomen round and wider than long, 

 and yellowish-gray in color with a greenish-white spot in the middle 

 and a black spot at either side : common in bushes. 



Fig. 662 Lathrodectus 

 mac tan s (Comstock). 



Fig. 663 Argyrodes tri- 

 gonum (Emerton). 



