Superfamily Argiopoidca 



opening of the epigynum nearly round; length of body of female 

 nearly one fifth inch. 



Dipcena crassiventris (D. cras-si-ven'tris). — Abdomen dark 

 brownish gray, with a light bent line behind; opening of the 

 epigynum heart-shaped. Length of body of female about one 

 seventh inch. 



Dipoena nigra (D. ni'gra). — Abdomen black. Length of 

 male six hundredths inch, female one tenth inch. 



Genus LATRODECTUS (Lat-ro-dec'tus) 



This is one of the two genera of the Theridiidne occurring 

 in our fauna in which the lateral eyes of each side are widely 

 separated. This genus is distinguished from the other (Episinus) 

 in having the abdomen globose. They are comparatively large 

 spiders, the females being the largest of the Theridiidae. 



This genus, as has been well stated by F. P. Cambridge 

 "comprises those very interesting spiders which, under various 

 local names, have been notorious in all ages and in all regions 

 of the world where they occur on account of the reputed deadly 

 nature of their bite." It may be added that this belief is not 

 shared by students of spiders, and has probably been suggested 

 by the strongly contrasting colours of the more common species, 

 which make them appear venomous to the credulous observers 

 Two species occur in our fauna. 



The Black Widow, Latrodechis mactans (L. mac'tans). — This 

 is a coal-black spider marked with red or yellow or both (Fig. 

 360). It varies greatly in its markings; the most constant mark 

 is one shaped like an hour-glass on the ventral aspect of the ab- 

 domen (Fig. 361). The female, when full grown, is often one 

 half inch in length, with a globose abdomen, marked with one or 

 more red spots over the spinnerets and along the middle of the 

 back; these spots, however, vary greatly in number and size and 

 may be wanting entirely. The male is much smaller than the 

 female, measuring about one fourth inch in length, and is even 

 more conspicuously marked, having in addition to the marks 

 of the female four pairs of stripes along the sides of the abdomen 

 (Fig. $62). It is a curious fact that immature females are often 

 marked like the males. 



This species is very common and widely distributed in the 



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