36 



AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



The spinning field, SF, is an elliptical slope, which is situated on the 

 inner side of the spinneret, and extends across the summit to the opposite 

 face of the tip. The basal part of the spinneret is cylindrical 

 and gradually grow r s smaller toward the spinning field. At the 

 lower or inferior edge is a row of long, strong branched bristles, 

 bb. On the inner surface, and at the border of the prolonged spinning 

 field, is a group of much shorter, stiff, simple bristles, sb. 



On each posterior spinning field is placed a number of spools, which 

 may be estimated roundly at one hundred and twenty. Besides these, there 

 are five larger spools, sp, which after Bucholz and Landois we may dis- 

 tinguish as spigots. Through these spigots issue a corresponding number 



of cylindrical and treeform glands presently to 

 be described. That part of the spinning field 

 which runs downward tow r ard the base is com- 

 posed of numerous rows of long, closely placed 

 spools, l.ss. ; while that part of the field on the 

 summit is covered with short spools, s.ss. (See 

 Fig. 23.) Of the spinning spigots (Fig. 23), 

 four stand close together in one group towards 

 the middle of the spinning field, and one of 

 them is situated in the lower part of the field 

 (near l.ss.), and appears to be covered by the 

 long spinning spools. Of the four grouped 

 spigots, three give exit to treeform glands; and 

 the one farthest towards the base is connected 

 a cylindrical gland. The isolated spool 



sp.t 



B.SS 



FIG. 24. Middle spinneret, largely mag- 

 nified, sp.c, spigot discharging cylin- 

 drical giand; ss, and s.ss, spinning sp, (near l.ss.) also discharges a treeform gland. 



o nriforrgS r nd. glandS;SP ' t>8pig0t The middle spinnerets are of a three faced 



pyramidal form. (Fig. 22, M, and Fig. 24.) 



The bases are directed towards the front, while their points, lying closely 



together, are turned immediately backward. They are uiijointed. 1 The 



spinning field is triangular, and occupies almost the entire slope 



6 of the spinneret from base to point. It contains quite a number 



etg of long spinning spools, which may be approximately estimated 



at one hundred and fifty. On each middle spinneret there are 



also three spinning spigots, of which two are close together at the tip, 



sp.c, and give issue to cylindrical glands. A little further back, another 



spigot gives exit to a treeform gland, sp.t. Along the inner base 



3. Aiite- are rows O f kri s U eS- The anterior spinnerets are of stouter pro- 

 rior Spin- , . , . , , . .*, . 



nerets portions and more conical shape than the posterior, from which 



and the middle spinnerets they are divided by quite an inter- 

 vening space. (See Fig. 22, A, A.) Their inner bases are almost in contact 

 and are divided only by a tongue like chitinous leaf, Fig. 21, t. 



1 See Bncholx and Landois. Merki-1 describes them as with two joints. 



