156 



AMKKICAN SriDKHri AND TllKlK Sl'n\iVlX( iWOKK. 



It loves the neighliorliood ol' water, but is foviml distrilmtcd widely 

 throuoliout the meadows and in the foliage of bushes and low trees. Its 

 snare is of a delicate texture, llnely spun, as a rule, hut oftentimes short 

 and straggling. It is placed either in a vertical, borizdulal, w inclined 

 position, but its general habit is horizontal, and with this class of Orb- 

 niiikcrs I have j)laced it. It is armed Mith a jiair of formidable jaws, whose 

 immense teeth and long fangs would ajjpear to givi.' it a great advantage 

 in its conflicts with enemies and efforts to secure food. 



In construction tlie orb of Tetragnatha extensa, as well as all other 

 species of the genus, corresponds very closely with that of tlie Orchard 

 sinder. Tbi' bub is ojien, and a series of udtclicd cdiiccntrics follows; then 

 comes the free space; tlicn the spiral space, the fuuiidatinn space, and tlie 

 foundation lines. ^ 



The position of 'i'etragnatba is miderncath tlie central jiai't of lu'r 

 snare. Her Ijody is usually stretched across the o})en hub. The legs do 



not radiate froni the body at open 

 angles, but are drawn very 

 Position close to the cephalothorax 

 ^ , at the fore part, and to the 



abdomen at the hinder ]iart 

 of the liiidy. The fore feet clasp the 

 radii at or beyond the notched zone, 

 or one foot holds fast to a line which 

 is stretchetl td the under part of tiie 

 web and bows downward to the foot. 

 The abdomen, as in the case of the 

 Orchard spider, is hitched by a sim- 

 ilar line to the orb. In this ])osition the spider sometimes swings almost 

 free from direct contact with her snare. The fore legs touch or approx- 

 imate near the middle, and the feet are curved outward. In spite of its 

 somewhat aw'kward apix'arance, Tetragnatha is remarkably lively in its 

 movements. 



When alarmed, Extensa runs down into the weeds or grass, and stretches 

 herself along the stem on wbicb she lias found refuge. Her legs bug 

 her body closely, even more closely than when suspended to her web as 

 just described. As her entire body is of a greenish yellow color, not 

 greatly different from that of the plant, it is somewhat diflicult to distin- 

 guish her from the stem on which she rests. This peculiarity is well 

 known among observers of the species wherever it is found, and is cited 

 as one of the examples of protective form mimicry. 



^ Description of Orbs. No. 1. Vertical ; 5 x4 in. ; n. z., J x J in. ; f. z., f x } in.; hub irregu- 

 lar meshed work. No. 2. 5 x 5 about ; f. z., J to J in. ; hub open, with few irregular threads. 

 No. 3. Nearly vertical; 3 n. sp. ; r. 10; sp. 21 below, 1.5 above. No. 4. Horizontal ; 4.1 x .5 in.; 

 r. 22, sp. V.i and less above ; n. z., i x i ; f. /., i x | ; o]icn luili. Xos. •">, (i, 7. ( )Hi iiiclinril :i1m .iit 45° ; 

 small, 3 to 5 in. in diam. Several orbs 2 in. diam. 



Fia. lis. Tetragnatha outstretched beneath the hub 

 of her snare. 



