348 



in the other it is 8 millim. long and 7'/ 2 broad; in a very nearly, 

 but not quite full-grown female I have found it 7 millim. long and 

 6'/ 2 millim broad; in another somewhat less developed female spe- 

 cimen it is 6'/ 2 millim. long and 5 3 /.-, millim. broad. In full-grown 

 or nearly full-grown specimens of D. plantarius ? the length of the 

 cephalothorax then appears to exceed its breadth by only V 2 millim., 

 whereas in D. fimbriatus £ the cephalothorax is 1 or 1% millim. 

 longer than it is broad, as I have found by measuring 10 full-grown 

 specimens in my collection. In young individuals of D. plantarius, the 

 difference between the length and breadth of the cephalothorax ap- 

 pears to be greater than in older specimens, and it will therefore 

 probably often be difficult to distinguish from each other younger 

 specimens of the two species. 



Even in very large individuals of D. fimbriatus (such as have 

 the cephalothorax 8 — 9 millim. long), the greatest breadth of the 

 eye-area scarcely exceeds 2 millim., whereas in equally large spe- 

 cimens of D. plantarius it is 2'/ 2 millim. In D. fimbriatus the 

 length of the legs in proportion to that of the cephalothorax varies 

 considerably; the cephalothorax is generally about as long as the tibia 

 of the 4 th pair, sometimes shorter, yet more often '/ 2 — 1 millim. longer, 

 than this tibia. The cephalothorax is moreover as long as (some- 

 times a trifle, at the utmost '/ 2 millim. longer or shorter than) me- 

 tatarsus + tarsus of the 1 st pair. In the full-grown specimens of D. 

 plantarius, which I have seen, the cephalothorax is as long as, or '/, 

 millim. longer than, the tibia of the 4 th pair, and 1 to l'/ 2 millim. 

 shorter than metatarsus + tarsus of the 1 st pair. The palpi are thicker 

 towards the extremity in D. plantarius than in D. fimbriatus. All 

 this applies to full-grown females only: in younger specimens of both 

 species the legs are usually shorter and coarser than in full-grown. 



In D. fimbriatus the vulva has the form of a large, not very 

 deep depression or fovea rounded at the sides, the raised and espe- 

 cially in the hinder part turgid margins of which approach each 

 other behind, without however meeting: the back part of the fovea 

 includes a brown disk, rounded at the sides and narrower behind, 

 and at the bottom of the fovea, in front of that disk, a couple of 

 elevated longitudinal lines may generally be perceived. The vulva in 

 D. plantarius is very similar to that in D. fimbriatus: it consists of 

 a large shallow depression, bounded at the sides by two low, cre- 

 scent-formed ridges or costse curved towards each other, which at 

 the extreme back part almost unite, there including a triangularly 

 heart-shaped disk. 



