Superfamily Argiopoidea 



D. 



Endite of the pedipalp not reaching to the end of the 

 claw of the chelicera; chelicerae projecting almost 



horizontally. P. 41 5. 



J . pallidula 



I)D. Endite of the pedipalp reaching to the end of the 

 claw of the chelicera; chelicerae projecting more verti- 

 cally. 

 E. Outer side of the chelicerae nearly straight. P. 414. 



7 . vermiformis 

 EE. Outer side of the chelicerae concave. P. 414. 



T. straminea 

 Tctragnatha elongata (T. el- 

 on-ga'ta). — The lateral eyes of 

 each side are not as far apart as 

 the anterior median and posterior 

 median eyes. The chelicerae of the 

 male are longer than the cephal- 

 othorax; those of the female are 

 about one tenth their length 

 shorter than the cephalothorax. 

 This is the largest of our 

 common species, the body of the 

 full-grown female being often 

 one half inch in length. In the 

 female (Fig. 424) the basal third 

 of the abdomen is usually swollen; the male (Fig. 425) is more 

 slender. It prefers damp situations; the web is often found 

 over running water, and frequently it is perfectly horizontal. 

 This is the Tetragnatha grallator of Hentz. 



Wishing to obtain a photograph of a web of Tetragnatha, and 

 not finding one in the field with a suitable background. I took 

 some spiders of this species to our insectary, and set them free 

 on the edge of a large tank through which water was flowing. 

 Here they remained unconfined, making no effort to wander to 

 the dryer parts of the building. I placed a section of a balustrade 

 upon the top of this tank, and the spiders stretched their webs 

 between its pillars. Figure 422 represents one of these. Before 

 taking the photograph the balustrade was taken from its place 

 over the tank and set in a vertical position before a suitable back- 

 ground. 



Tetragnatha externa (T. ex-ten'sa). — The lateral eyes of each 



411 



Fig. 423. CHELICERA OF TETRAGNATHA 



a, T. slraminea b, T. pallidula 



