ARACHNOIDEA. 581 



Atax FABR. (in part), DUGES (and Arrenurus ejusd.), Palps 

 .ubulate, with last joint falcate, or unguiculate. Ocelli two, lateral, 

 jlistant. Body in the males of some species narrowed posteriorly 

 md produced into an appendage truncated or cylindrical (Arrenurus 

 ). 



Add sub-genera : Nescea, Fiona, Hygrolates 1 , Hydrochoreutts, 

 Atractides, Acercus, Marica KOCH. 



Comp. Uebersicht des Arachnidensy stems, nites Heft, erst Abtheil. 1842, 

 and P. T. VAN BENEDEN Recherclies sur I' Atax ypsilophora, Hydrachna, 

 concharum. Mem. de I'Acad. royale de Belgique, Tom. xxiv. 



Family VIII. Bdellea. Kostrum subulate, separated from 

 ody by stricture, often large, resembling a head. Body oblong, 

 ostly parted by a transverse groove or stricture between the 

 cond and third pairs of feet. Palps inserted at the base of ros- 

 um, lateral, divaricate, large. Mandibles terminated by an in- 

 irved claw or two small fingers. Ocelli mostly distinct, four, 

 eet cursorial, attenuated towards the apex, terminated by two 

 nail claws. 



Bdella LATR., Scirus HERM. Palps filiform, geniculate or in- 

 irved. Feet subequal. 



Bdella DUGES, KOCH, Ammonia KOCH, Scirus DUGES, KOCH, 

 Eupalus KOCH. 



Comp. Uebersicht des Arachnidensy stems, nites Heft, 3, pp. 73 80. Sp. 

 Bdella vulgaris LATR., HERMANN Mem. Apter. PI. 3, fig. 9, KOCH, HERRICH- 

 SCHJSFFER D. Ins. Heft 167, tab. 8. 



Cheyletus LATR. Palps thick, incurved, filiform. Feet slender, 

 iterior longer. Ocelli none or indistinct. 



See figures in KOCH, HERRICH-SCH^EFFER, Heft. 167, Tab. 20, 

 21, 22. 



Family IX. Trombidina. Palps chelate, with last two joints 

 >posite, the external (penultimate) representing an incurved 

 aw. Feet terminated by two small claws, cursorial. 



Trombidium FABR. (exclusive of some species). Two mandi- 

 es horny, unguiculate, included in labium. Body suboval or 



1 In the neighbourhood of Hydrdbates KOCH probably Pontarachna PHILIPPI ought 

 be placed, if it is to be considered a distinct genus ; a very small ffydrachna observed 

 the bay of Naples. Annals of nat. History, vi. 1841, pp. 98 100. 



