Or 
ANELOSIMUS.—THWAITESIA, BEE 
2. Anelosimus studiosus. (Tab. XXXVII. fig. 16, ¢ ; 17, 2.) 
Theridium studiosum, Hentz, Journ. Bost. Soc. Nat. Hist. vi. p- 274, t. 16. fig.5 (9) '; Spid. U.S. 
p. 145, t. 16. fig. 5 (9)*; Keyserl. Spinn. Amer., Therid. i. p. 20, t. 1. figg. 7, 7a, b(?), 
7¢($)°*; Banks, Proc. Calif. Acad. Sci. (3) i. p. 236+. 
Theridion studiosum, E. Simon, P. Z. S. 1897, p. 862°. 
Hab. Nortn America !23,—Mexico, Orizaba, Teapa (H. H. Smith), Tepic+; Guate- 
MALA (Sarg).—CoLomBiA?; VuenezueLA?; Peru®; Brazit, Rio Parana® (Rogers*) ; 
ANTILLES, St. Vincent °. 
Since no American arachnologist has hitherto identified the species which might 
most reasonably be regarded as A. studiosus (Hentz), one must for the time being 
accept Keyserling’s determination. There are before me female examples, in his 
collection, from the Mississippi, Argentina, and Peru; they are identical with others 
from Venezuela in the same collection, and also with specimens from St. Vincent, 
identified by Simon as Theridion studiosum, Hentz. These, however, are quite 
different from the females from Bogota in Keyserling’s collection labelled 7’. studiosum. 
The latter more nearly resemble A. jucundus, 2, var., see Plate. 
The male from Rio Janeiro, labelled by Keyserling 7. studiosum, is, again, totally 
dissimilar from A. jucundus. It is possible, however, that both 7. studioswm, Hentz, and 
T. gucundum, O. P.-Cambr. (as Simon thinks probable), the varieties here figured, and 
also those from Bogota, are all one and the same species, the larger and more highly 
developed examples being 7. jucundum, the smaller and more slender being 7. studiosum 
(sec. Keyserling and Simon). 
It is also possible, on the other hand, that there are several species of these social 
spiders, and that the varieties above noted may prove to be really good species. I 
cannot at present reconcile myself to either view, but must be content with giving 
drawings and descriptions of them. 
There is not the smallest doubt in my own mind that Theridion eximium, Keyserl., 
of which the type, 2, is before me, is quite distinct from the females of 7. jucundum 
and 7. studiosum. 
Simon (Hist. Nat. Araign. éd. 2, i. p. 548) regards 7. eximium, Keyserl., as identical 
with his Anelosimus socialis [Ann. Soc. Ent. Fr. 1891, p. 7, t.2(2)]. It is scarcely 
probable that this species, so abundant in Venezuela and Brazil, does not occur in 
Central America, and since it belongs to the same group as A. jucundus and A. studiosus, 
I give a figure of the palpus and vulva (Tab. XX XVII. figg. 12, ¢; 13, 2); the latter 
from Keyserling’s type, the former from an example from the Lower Amazons, where 
T met with it in abundance. 
THWAITESIA. 
Thwaitesia, O. P.-Cambridge, P. Z. S. 1881, p. 766. 
Type 7. margaritifera, O. P.-Cambr. Ceylon. 
The members of this genus remind one of both Theridion and Argyrodes, the 
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