200 T. THORELL, 
Sub-fam. I. ERESINA. 
This sub-family includes for the present 2 genera, Æresus WALCK. 
and Dorceus C. KocH (exotic and distinguished by long, three-jointed ma- 
mille). C. KocH has indeed divided Æresus into two genera, Erythrophora 
and Æresus +), but as the genus Erythrophora can hardly be distinguished 
from Æresus by anything else than a difference of colour, it seems to me 
not deserving of preservation. 
Gen. 1. ERESUS Warck. 1805. 
Deriv.: probably éoeidw, press against, inflict, attack. 
Syn.: 1805. Eresus WALCK., Tabl. d. Aran., p. 22. 
1837. Chersis ID., H. N. d. Ins. Apt., I, p. 390 (ad partem). 
1850. Eresus C. Kocx, Uebers. d. Arachn.-Syst., 5, p. 50. 
1850. Erythrophora ID., ibid. 
1861. Eresus Brackw., Spid. of Gr. Brit., I, p. 45. 
1864. As [Eresa] Sim., H. N. d. Araignées, p. 299 (ad max. part.). 
Type: Eresus cinnaberinus (OLIV.). 
In the few species of this genus known to me, the calamistrum is 
but slightly developed. In a © of Æ. lineatus LATR. or E. acanthophilus DUF.?), 
which has the upperside of the two posterior metatarsi somewhat flattened, 
the calamistrum is plainly visible on the external edge; but in the male of 
E. cinnaberinus, in which these metatarsi are cylindrical as in the other 
legs, I cannot perceive any calamistrum distinguishable from the adjacent 
fine hair. The infra-mammillary organ is on the contrary easily seen in 
both species: in Æ. lineatus it forms a very narrow, uniformly broad, trans- 
versal area, which appears to be divided into two by a middle suture, and 
exhibits two rounded foveæ *), one on each side, and a small depression 
behind these, near the spinners. 
The tarsal claws of Æresus are short, but extremely broad and strong, 
1) Uebers. d. Arachn.-Syst., 5, p. 70. 
2) This species was first described by LATREILLE in the 2% Edition of Nouv. 
Dict. d'Hist. Nat., X, p. 393 — which I have not been able to consult — under the 
name of ” Hrése rayé" (see for inst. WALCK., Ins. Apt., I, p. 399), probably also with 
the Latin name Æresus lineatus: at least it is by Aupouin, in Dict. class. d'Hist. 
Nat., VI, p. 253, called ” Eresus lineatus LATREILLE ". 
3) Conf. note, p. 30. 
