174 Mr. J. O. Westwood's Ohservations 



nests with a single trap-door as of that species, as we are led to 

 the conclusion, that A. nididans makes a double valve, similar to 

 that figured by Brown in his 3rd figure, and described by Olivier, 

 from M. Badier's Guadaloupe specimen, whilst the single-valved 

 nest is the work of a distinct species ; and, as Mr. Kirby, in his 

 " Bridgewater Treatise," has figured the single-valved nest of the 

 Jamaica insect, whilst another figure of the nest and spider, from 

 specimens in the British Museum, has been published in Griffith's 

 " Animal Kingdom," Arachnida, pi. 7, under the name of Mygale 

 nitida, without any reference to the two species noticed above, 

 we may adopt this name for the single-valved species, until it shall 

 be determined (as I have no doubt will be the case) that the dif- 

 ference in the formation of the valves is the effect of accidental 

 circumstances. 



There are also figures of the single-valved nest and its architect 

 in the " Naturalist's Miscellany" of Shaw and Nodder, pi. 614. 



At the period when Latreille made his examination of the 

 Banksian collection, the genus Mygale had not undergone any 

 dismemberment ; consequently the large Jamaica species was re- 

 tained by him under Fabricius's name of nidulans in that genus, 

 and as he observed that the insect " se rapproche de la Mygale 

 pionniere de M, Walckenaer," it has been placed without further 

 comment in the subgenus Cieniza, with the Mygale jyionniere (M. 

 fodiens) and M. magonne(^M. ccementaria), by all subsequent writers. 

 An examination of Mr. Sells's specimens has however convinced 

 me that they belong neither to the sub-genus Cteniza, nor yet to 

 the genus Mygale, being referable to the genus Actinopus of Perty, 

 {Sphodros of Walckenaer or Pachyloscelis, Cratoscelis, and Acti- 

 nopus of Lucas) ; and most probably identical with the Sprodros 

 Ahhotii of Walckenaer (Hist. Nat. Ins. Apt. 1, p. 247), so named 

 in honour of the Georgian entomologist. Abbot, who has illus- 

 trated it in his drawings under the name of the purse- web spider, 

 (No. 36 of the 1 4th vol. of his Collections of Drawings in the British 

 Museum Library, No. 7956, Plutarch 126 E.) It is also probably 

 identical with the Mygale truncata of Hentz, (Boston Journal of 

 Nat. Hist. vol. iv. No. 1. "Descriptions of Spiders of the United 

 States," Species 1). Mygale nidulans, Fab., Walck., if distinct from 

 that of Latrielle, is also most probably a species of the same genus 

 Actinopus, which comprises several other species whose economy 

 has not been observed. 



Another species of trap-door spider remains to be described, 

 which was forwarded to this Society from Barbary by Mr. Drum- 

 mond Hay, together with its nest, which likewise belongs to the 



