Superfamily Argiopoidea 



female. The very characteristic form of the species make them 

 the most easily recognized of all of our spiders. 



Three species are listed as occurring in the United States; 

 but the following is our only common one; the others are found 

 in the extreme South or Southwest. 



Gasteracantha cancrijormis (G. can-cri-for'mis). — This is a 

 spider whose remarkable shape and conspicuous, strongly con- 

 trasting colours are sure to attract attention. The adult female 

 (Fig. 556) measures about one third inch in length and is about 

 as wide as long. The abdomen is leathery and is armed with a 



fringe of spinose processes. The ground 

 colour is yellow, marked with black 

 spots, which vary in number and shape. 

 This is a southern species, which is 



Fig. 555. 

 MICRATHENA GRACILIS 

 SHOWING THE PROJEC- 

 TION, ON THE LOWER 

 SIDE OF THE ABDOMEN, 

 1 HAT BEARS THE SPIN- 

 NERETS 



Fig. 556. 

 GASTERACANTHA 1 ANCRIFORMIS, FEMALE 



found in the Gulf Slates, where it is 

 common in the more southern portions. 

 The web is built between the 

 branches of shrubs and trees, and fre- 

 quently in the tops of tall trees. It is a complete orb, and is 

 either vertical or inclined; the hub is open; the notched zone 

 is narrow; the free zone is wide; and there are many viscid 

 spirals. There is no retreat, the spider resting on the hub with 

 its body over the open space. I have never observed a stabili- 

 mentum in a web of this species. 



A remarkable feature of the webs of this species is the fre- 

 quent occurrence in them of series of flocculenl tufts of silk at- 

 tached to either the radii or to some of the foundation lines (Fig* 

 557). These tufts are composed of a mass of fine threads, like 

 those of which a stabilimentum is made. I he only suggestion 

 that 1 can make as to the ii^e of these tufts is that they may 



513 



