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AMERICAN PPIDEKS AND Till: 11: h;riNNING\VORK. 



Mandi- 

 bles. 



aa- 



Tlif jiart tif the caput included between the two roM^s of eyes is calUnl 

 the eye space. The space between tlio front row of eyes and the lower 

 iiuirgin of the face where it joins upon the mandibles is the clypeus 



(Cp). Tliat between the upper row of eyes and 

 the vertex (v) of the cai)ut is the forehead. The 

 entire .space thus occupied, from the vertex to the 

 margin of the clypeus, is the face or facial space. 

 The mandibles (mb) are two jaw like organs 

 attached to the head beneath the margin of the 

 clypeus, will I in whicli they articulate lat- 

 erally. Tliey are placed perpendicularly, 

 or inclined more or less backwanl or 

 toward the sternum. In shape they are conical or 

 subovate. Each mandible is composed of two parts, 

 the base or falx (fx) and the fang (fg). Tlie fang 

 is a curved movable tootli, smooth, hard, and 

 pointed. It is hollow, pierced on the inner side 

 Fig. 10. Ventral view of Argiope near the poiut witli a suiall liolo, wliich opens into 



argyraspis. ps, palps; mb, v i j. i? rpi 



mandible; dg, digital joint of a slight furrOW. illC 



palps; ra, radial joint; hu, holloW of the failg is 

 humeral ; cu, cubital ; ax, ax- • i i i 



iUary; mx, maxilla;; lb, labi- OCCUpied by a meml)ra- 



um;sm, sternum; ex, coxa of j-^^^g ^^^^ wllich Icads 

 the leg; gl, breathing gills; ep, 



epyginum ; sp, spinnerets rep- UpWard tO a g la lid 



resented clcsed; ac, anal elos- ^^^^^^^l witlliu tllC falx. 

 ure. " 



This gland is sujiposetl 

 to secrete a poisonous liquid. 



The falx is covered with hair, especially 



near the base, and at the apex is formed 



into a toothed groove or sheath 



into which the fang is folded down 



when at rest. 



The sternum (sm) is a cordate plate which 

 forms the under part of the shell of the 

 cephalothorax. It has four inden- 

 Sternum. ^.^^j^^g ^^ g^ch side, which mark 

 the insertion of legs. On the for- 

 ward part at the middle is placed the labium 

 or lower lip (lb), a subtriangular or semi-ovate 

 organ of the mouth. (See Fig. 10.) 



Oppo.sed to the labium and above it is 



Fig. 11. Dorsal view of Epeira insularis. 

 ab, abdomen ; b, base ; ap, apex of ab- 

 domen ; pt, pits which mark the attach- 

 ment of abdominal muscles ; cp, ceph- 

 alic part of cephalothorax ; t p, thoracic 

 part; mb, mandibles. 1, 2, 3, and 4, 

 the legs represented in their order, 

 first, second, third, and fourth. Teh, 

 trochanter of the leg; ex, ccxa; fm, 

 femur; dg, digital, ra, radial, cu, cu- 

 bital, hu, humeral joint of ])alps. 



the u]ipcr 'li]), a slight liair tipped iirojectiou, 



which is the termination of the i)alate. On eitlier side of the 

 labium is placed one of the maxilla; or lower jaws. They vary 



in form, the variation giving good generic characters. They have a 



Maxillse. 



