Superfamily Argiopoidea 



are A. gigas and A. trifolium. The full-grown females measure 

 from one half to three quarters of an inch in length; but they 

 are easily distinguished from the large angulate species of Aranea 

 by the absence of shoulder-humps on the abdomen. 



Each of these two species varies greatly in colour and in 

 markings; and as certain varieties of the two species present 

 the same type of markings, it is necessary to make use of structural 

 characteristics in separating them; this can be done as follows: 



A. Each lateral half of the epigynum of the female divided by a 

 prominent oblique furrow; ventral side of the abdomen 

 black in the middle with a semicircular yellow spot on 

 each side; the tibia of the second legs of the male thickened 

 and armed with many, short, thick spines. P. 475. 



A. gigas 

 AA. The lateral halves of the epigynum not divided by a furrow ; 

 ventral surface of the abdomen usually lacking the semi- 

 circular yellow spots; the tibia of the second legs of the 

 male not thickened. P. 479. A. trifolium 



Aranea gigas (A. gi'gas). — This is an exceedingly variable 

 species in size, colour, and markings. The full-grown female 

 measures from one half to three quarters of an inch in length. 

 The cephalothorax is dull yellow with slightly darker lines in 

 the middle and at the sides. The upper surface of the abdomen 

 varies in colour from light yellow with dark purplish brown mark- 

 ings, through a light grayish brown with markings indistinct, to 

 chocolate brown or dark gray with prominent light markings. 



In most cases this species is readily distinguished from the 

 following by the markings of the ventral side of the abdomen, 

 which bears a broad black band in the middle with a semicircular, 

 yellow spot on each side. In this respect this species closely 

 resembles A. cavatica (Fig. 488) and many others; but as a rule 

 A. trifolium lacks the yellow spots except in the young. 



In what must be considered the typical form of this species, 

 being that which was first described, the dark spots are gray or 

 brown with a purplish tint and the light parts are white or yellow; 

 in this form there is comparatively little of the lighter colour, 

 except an irregular spot on each front angle of the abdomen, a 

 broken median line, and a faint outline of the folium (Fig. 493). 



475 



