166 AMERICAN SPIDERS 



it. The mouse was a small one, measuring about one and a half 

 inches from the point of its nose to the root of the tail. 25 



This spectacle, watched with amazement by many people and 

 interrupted by the clumsiness of a "meddlesome boy" who acci- 

 dently broke the web (instead of by the intervention of the 

 S.P.C.A., as, is usually the case), is a compliment to the strength and 

 elasticity of the multiple threads of the line weavers, and to their 

 engineering prowess in elevating tremendous loads by block-and- 

 tackle methods. 



A high percentage of our comb-footed spiders belongs in the 

 genus Theridion, perhaps the largest of all spider genera and typ- 

 ified by Theridion tepidariorum. Most other species are smaller 

 and more brightly colored. The globose female of Theridion differ- 

 ens, one-eighth inch long with a reddish brown abdomen marked 

 above by a red, yellow-edged stripe, places her large white egg sac 

 in the nest. Her web is found on low plants of all kinds, and con- 

 sists of a small tent, barely covering the spider, from which an ir- 

 regular network of lines spreads out across the limits of the plant. 

 Representative of another species group is Theridion frondeum. 

 This spider has a pale white or yellow body boldly marked with 

 black, but extremely variable in color and pattern. Some examples 

 are almost entirely white, unmarked, whereas others have narrow 

 dark lines or bands on the cephalothorax, and small black spots, 

 dusky bands, or dark stripes and patches on the abdomen. These 

 handsome theridiids, represented by one or more species almost 

 everywhere in the United States, live on low plants and prefer 

 moist, lightly shaded areas in woods or along streams. 



Closely allied to the theridiids are the species of Tidarren, the 

 best known of which, fordum, resembles tepidariorum in size and 

 coloration and lives in similar situations. Whereas the males of 

 Theridion are inferior to the females in size a disparity reflected 

 chiefly in the lesser bulk of the abdomen, the males of Tidarren are 

 babies by comparison. The female Tidarren fordum is often nearly 

 one third of an inch in body length, whereas the males are rarely 

 larger than one eighteenth of an inch. At the proper season these 

 pygmies often cluster in the webs of the females, usually a dozen 

 or more to a web and rarely fewer than two or three, and seem to 

 be tolerated. The males of the known species of this genus carry 



^McCook, ibid. 



