136 AMERICAN SPIDEKS AND THEIR SPINNINGWORK. 



Genus EPEIRA Walckenaek. 



The original genus Epeira of Walckenaer has been divided and subdivided at various 

 times, yet still contains by far the greatest number of orbweaving species, not only in the 

 United States, but other parts of the world. That it must further be subdivided is apparent 

 to any one who has given much attention to the species which are grouped thereunder; 

 but equally plain that it will be difficult to distinguish sharply the characteristics upon 

 which good generic differences may be based. The following are the principal character- 

 istics herein held to mark the typical Epeira.' 



The cephalothorax is moderately high and oval, more or less shortened or cordate 

 the corselet for the most part being well rounded. It is moderately high, the fosse placed 

 near the centre of the summit, from whence the corselet slopes more or less sharply to the 

 base, which is truncated and often indented. The corselet grooves are sufficiently distinct; 

 the cephalic sutui-e well marked. The margin of the corselet is often a narrow belt fi-ee 

 from pubescence more or less shelving to the articulation with the legs. The head is lowly 

 arched, somewhat depressed at the face, which is wide, though narrower than the coreelet, 

 and somewhat quadrate. The sternum is shield shape or cordate, somewhat longer than 

 wide ; the labium longer than wide, strong, half as high as the maxiUse, which are as 

 wide, or nearly as wide, as long. 



The eyes are placed in three groups, of which the side eyes are upon tubercles or 

 elevated bases, the four middle eyes upon a rounded eminence, the ocular quad being in the 

 form of a quadrilateral whose greatest width nearly equals the length. The front side of 

 the quad is usually a little wider than the rear. The space between the sidefiont and 

 midfront eyes is equal to 1.5 times the area of the latter, or from 2 to 2.5 the intervening 

 space thereof. The space between the siderear and the midrear eyes is usually greater than 

 the above. The clypeus is low, rarely exceeding 2 to 2.5 times the diameter of the midfront 

 eyes. The eye rows are not widely separated at their greatest point of divergence and 

 closely approximate at the sides; the fi-ont row is slightly recurved, the rear row slightly 

 procurved. 



The legs are in order of length 1, u', 4, 3; stout in all the joint.*; the tarsus and meta- 

 tarsus gradually diminishing in size, and not noticeably thinner than the other joints. 

 They are clothed heavily with hairs and bristles, and abundantly with strong spines. The 

 palps in the female are armed as tlie legs; the digital joint with a strong claw; longer 

 than the radial joint; the cubital joint being about half the length of the latter, and the 

 humeral joint aiijiroximating the length of the digital, but usually longer. The abdom.en 

 is usually subglobose or oval, rounded at the base and diminished at the apex, or is a 

 triangular ovate. The spinnerets are distal and the base overhangs the cephalothorax 

 sometimes for half its length. The skin is soft and pubescent. The epigynum has generally 

 a prolonged scapus. 



The male in general form and markings resembles the female. Tibia-II is frequently 

 widened at the tip, and in some species provided with strong denticulate clasping spines. 

 The coxifi are often marked by spurs at the articulation with the trochanter, or upon the 

 base. He is commonly much smaller than the female, but sometimes nearly equals her 

 in size. 



It will probably be observed in the following descriptions that the above specifications 

 of the typical Epeira are not strictly adhered to, and in some points indeed are widely 

 divergent therefrom. But a strong indisposition to multiply new genera, together with the 

 confusingly interblemled characteristics above referred to, have prompted to, if not justified 

 such a course. No doubt future students, who may have a greater amount of material in 

 hand, will be able not only to indicate necessary divisions, but to unite some of the genera 

 already created from this overflowing group. 



» For the technical terms used in description of species see Chapter VI., page 124 sq. 



