424 



ARACHNIDA 



C. fissiceps (Cambridge). Body 1.5 mm.; abdomen round, and 

 orange in color; head black around the eyes; the head of the male 

 extends fonvards, forming two humps: veiy common on small bushes. 



Family 9. EPEIRIDAE.* 

 Round-web spiders. Usually large spiders with long legs and an 

 abdomen which is rounded or ovoid and often provided with humps; often 

 brightly colored; cephalothorax short, low in front with the eyes near 



the front edge and in 3 transverse 

 groups, the 2 lateral pairs being close 

 together and separated from the mid- 

 dle eyes; 3 terminal claws on each 

 foot, usually with accessory spines 

 also. The web is round and regular, 

 Avith radiating spokes joined by cross 

 threads (Fig. 667). The latter form 

 2 spirals, an inner spiral that begins 

 in the center and winds outwards, 

 covering usually less than a quarter 

 of the finished web, and an outer 

 spiral that begins at the edge and 

 winds inwards, covering a large part 

 of the web. The outer spiral is 

 formed of a sticky thread which holds 

 the insects flying against it. The 

 spider usually tears down its web and builds a fresh one every nio-hf 

 this may be for the purpose of renewing the sticky thread, which gradu- 

 ally hardens. About 120 American species are known. 



Key to the genera of Epeiridae here described : 

 «i Abdomen not elong:ate, usually round or ovoid 



\ mntrZ'?''''''?^^'''";"^'^' large brL.htly colored spiders.l. Argiope 

 O2 ±lmder row of eyes not curved or ouly slightly so. 

 Ci Thorax without a deep longitudiiiaf furrow 



d^ Head and thorax separated by a deep transverse cervical groove. 2. Cyclosa 

 d., ^o distmct cervical groove; thorax usually with a V-shaped furrow 

 Ci Abdomen without spines. "iiow. 



/i Web entire 



/. Web lacking a large segment'. ■.'.'.'.'.■. 4 y™'' 



e. Abdomen with prominent spines r" "k'^^^^I, 



c Thorax with a deep longitudinal furrow ';. /. ^IanZ^ 



a. Body elongate and light-colored. Mangora 



6, Groove between the spiracles curved ninrk.dly 7. TETRAG^fATiiA 



h This groove nearly straight \ 8 L™"e 



Conn* tad ''^^i''g^^9V^'i'.«7 ^V.^^^^'^'""^' J^l-irulne," Uy J. n. Emorton. Trans. 

 132, 1S93 *' "-^"'^'-i^an Spiders." etc.. by H. McCook. Vol. 3, p. 



Fig. 6G/— An orb web (Emerton). 

 1, inner spiral; 2, outer spiral: 3. 

 strand going to the nest. 



