ARACHNIDA. 
187 
Xt/sticus. Of this genus L. Koch (/. c.) describes the following new spe- 
cies from Queensland : — X. dimidiatus^ p. 210 ; X. piltda^ p. 212 ; X. adustm^ 
p. 214; X. himacidatm, p. 216; X, nigropunctatus, p. 217; X, evanidus^' 
p. 218 ; and X. puskdosus, p. 220, 
Xgsticus hicoloi'f L. Koch, I, c. p. 867, Syra. . 
DRASSIUiE. 
Argyroneta aquatica. F. Plateau lias published (Bull. Acad. 
Sci. Belg. xxiii. pp. 96-125) some notes on the natural history 
and development of this species. The author describes the 
development of the ovum and of the embryo, and the 
growth and habits of the young after hatching. The mature 
Argyroneta, according to Plateau, forms two different subaquatic 
tents — one its domicile, not previously noticed, the other, which 
is already well known, for the reception of its eggs and young. 
The fabrication of these apartments is described, and they 
are figured in the accompanying plate. With regard to the 
power possessed by the Spider of carrying down air adhering to 
its body. Plateau ascribes it to the stability presented by the sur- 
face of contact of air with a liquid, provided the surface be suffi- 
ciently small, the coating of air carried by the Argyroneta on 
its abdomen being broken up into numerous small surfaces by 
the points of the bundles of hairs. The development of the em^ 
bryo in the ovum is represented in figs. 3-6 of the plate. The 
paper is reported on by Poelman (/. c. pp. 71-73). 
L. Koch has published the seventh part of his revision of the 
Drassidce, which is entirely occupied by descriptions of species 
of Cluhiona. The epigynes and male palpi of most of the species 
are figured. C. ' amarantha (Walck., Blackw., &c.) = C. incomta 
(C. Koch) = C. pallidula (Clerck) . 
Ohlert (Aran. Preuss.) arranges the Prussian species of this family in the 
genera Argyroneta, Amaurohms, Drassus, Melanophora, Pythonissa, Cluhiona, 
Cheiraeanthmm, Anypheena, Macaria, Dysdera, and Segestria, the last 2 genera 
forming his family Dysderidee. The total number of species described by him 
is 39. 
Kempelen (Verh. zool.-bot. Ges. in Wien, xvii. pp. 647-650) describes the 
mature and immature forms of Drassus lapidicola, and remarks upon their 
characters. 
Segestria perjida. The occurrence of this species in Britain is confirmed by 
Blackwall (Ann. Mag. N. H. 3rd ser. xx. p. 212). 
New genus and species : — 
Thysa, g. n., Kempelen, 1. c. p. 607. Allied to Pythonissa, but with only 
six eyes, those of the anterior row much larger than those of the third, and 
the latter larger than those of the middle row. Sp. T. pyihonissreformis, sp. n., 
Kempelen, 1. c. p. 607, taf. 14 B, Hungary. 
Drassus delicatus, Blackwall, Ann. Mag. N. H. 3rd ser. xix. p. 391, India. 
Drassus collingsice, Blaclcwall, Ann. Mag. N. H. 3rd. ser. xx. p. 209, Sark. 
Drassus pallidipalpis, Bilimek, Verh. zool.-bot. Ges. in Wien, xvii. p. 906, 
Gave of Cacahuamilpa, Mexico. 
