xv CLASSIFICATION 595 
localities, such as the Isle of Portland, and occurs, though less 
commonly, all over the country in similar situations, and under 
the loose bark of trees. It is half an inch in length, with a 
chestnut-coloured cephalothorax and legs, and dull yellow abdomen. 
A closely allied species, D. crocota, also occurs more rarely. 
Harpactes hombergit is common in vegetable débris and under 
decaying bark. It is about a quarter of an inch in length, of 
slender form, with black-brown cephalothorax and clay-coloured 
abdomen. The legs are yellowish and annulated. More than 
forty exotic species of Dysdera and twenty-four of Harpactes 
have been described. Another genus of the Dysderinae is Stalita, 
which comprises three species, inhabiting the caves of Dalmatia 
and Carniola. 
(i.) The SEGESTRIINAE include two genera, Segestria and 
Ariadna. 
Segestria senoculata occurs in England in similar localities 
to those where Dysdera cambridgw is found. It is not much 
smaller than that spider, and has a dark brown cephalothorax 
and legs and a dull yellow abdomen, with a series of adder-like 
diamond-shaped black markings along the middle. Two other 
species have occurred on rare occasions in England, and twelve 
more are recorded from the various temperate regions of the 
world. 
Ariadna is the only Dysderid genus which invades the 
tropical regions. It includes about twenty species. 
Fam. 12. Caponiidae.—This is a small family of three genera 
and about twelve species, remarkable in having no pulmonary 
sacs but five tracheal stigmata,’ and ih the peculiar arrangement 
of their six spinnerets, those which are ordinarily median being 
in the same transverse line with the anterior ones. 
The single species of Caponia (C. natalensis) inhabits South 
Africa, while Caponina has two species in South America. These 
spiders are eight-eyed, but the two median posterior eyes are 
much the largest, and these alone are present in the remarkable 
genus ops, of which several species inhabit South America and 
adjacent islands. 
Fam. 13. Prodidomidae.—This small family includes about 
1 According to Bertkau (in a letter to Simon, cited in Hist. Nat. des Ar. i. 
p- 327), two pairs of linear stigmata under the anterior part of the abdomen lead, 
to pulmonary sacs, but to tracheae. 
