Superfamily Argiopoidea 



serve as lures for the attraction of midge-eating insects, which 

 in their efforts to capture the supposed midges fly into the orb. 

 This method of decorating the web has been observed also 

 with certain exotic members of this genus. 



Genus MICRATHENA (Mi-cra-the'na) 



Our representatives of this genus are of moderate size and 

 are brightly coloured. The cephalothorax is longer than wide; 

 the dorsal aspect of the abdomen is flattened and, with adult 

 females, it bears on its margin several pairs of spines, varying 

 in size and shape. The males resemble the young females in 

 form and colour. 



This is the genus Acrosoma of most American writers on 

 spiders; but it is believed that Micrathena is the older name. 

 The genus is represented in this country by four species. 



Micrathena sagitiata (M. sag-it-ta'ta).— The arrow-shaped 

 Micrathena is easily recognized by the striking form of the ab- 

 domen, which is narrow in front and is terminated behind by two 

 large spreading spines (Fig. 558). The abdomen bears also two 

 other pairs of spines, one near the base, and the other between 

 these and the large caudal spines. The cephalothorax is yellowish 

 brown with white edges. The abdomen is white or bright yellow 

 above spotted with black. The spines are black at the tip and 

 bright red at base. The ventral aspect of the abdomen is darker 

 than the dorsal and is marked with black bands and yellow spots. 

 The adult female measures a little more than one fourth inch 

 in length. 



The male (Fig. 559) is about one sixth inch in length. The 

 abdomen is a little widened behind and bears slight humps in 

 the place of the spines of the female. 



This species is the Epeira spinea of Hentz. It is very common 

 in the South; and Emerton reports it as common in Massachu- 

 setts and Connecticut. 



The web is made on low bushes and is a very symmetrical, 

 inclined orb, with many radii, and closely placed spirals; that of the 

 adult is about one foot in diameter. The hub is open; there is no 

 free zone, the spiral guy-line being left in the space between the 

 hub and the viscid spiral. Figure 560 represents the central 

 portion of an orb natural size. There is no retreat, the spider 



5'4 



