1012 MB. OLDFIBLD TU0MA5 Olf THE [Dec. 15, 



anterior side shortest, the posterior spots are largest ; the fore 

 half is bounded by a broadish lateral band of cream-colour, and 

 from the inner extremities of the band a curved narrow tapering 

 stripe of the same hue runs inwards and backwards, but their 

 points do not meet; following this towards the spinners is a 

 curved transverse cream-coloured stripe, being only linear iu the 

 middle, close behind which again is a short curved transverse 

 cream line connecting the bases of two triangular patches of 

 the same hue ; spinners short, compact, underside dusky, 

 margined with a cream-coloured sufEused border. Colulus short, 

 triangular. 



Eeceived from Prof. Traill ; taken on the Amazons. 



EXPLANATION OP PLATE LIL 



Fig. 1. Aethis decoUatus, J (p. 1007). la. Profile, li. Eyes from above 

 and behind. \o. SXaxilla;, labium, and sternum. Id. Sternum, 

 showing more clearly posterior elongation and angular points. 

 1 e. Genital aperture. 



2. Fnula wallacii, $ (p. 1009). 2 a. Profile. 2 4. Abdomen from 



behind. 2c. MaxiiliB, labium, and sternum. 2d. Lines showing 

 natural length and width of Spider. 



3. Labdacus immastoides, (£ (p. 1009). 3a. Eyes. 3i. Palpus. 3 c. 



Portion of palpus. 3 d. Labium and fore part of sternum. 



4. Stephanopoides brasiliana, cf (p. 1010). 4 a. Eyes from above and 



behind. 4 6. Palpus. 



6. On the Genera of Rodents : an Attempt to bring up to 

 Date tlie current Arrangement of the Order. By 

 Oldvield Thomas, F.Z.S. 



[Eoceived November 1.'), 189G.] 



Just over twenty years ago, in 1870 \ Mr. E. E. Alston con- 

 tributed to this Society his invaluable paper " On the Classification 

 of the Order Glires," a paper which in its broad outlines has 

 formed the basis for almost every Museum Catalogue, compiler's 

 list, and general text-book that has been written since it appeared. 

 Based as it was on the earlier works of Waterliouse, Gervais, 

 Brandt, and Lilljeborg, Alston's arrangement has in this way 

 received almost universal sanction, and the present writer is 

 far from wishing to alter the essential characteristics of the 

 scheme. 



But, owing xmrtly to Alston's not having seen examples of many 

 of the genera included, and p.irtlj to tlie great increase in the 

 number of known forms that has taken place since he wrote, his 

 paper has gradually become somewhat obsolete in its detailed 

 arrangement of the subfamilies and genera, however correct his 

 positions for the suborders and families may still be considered 

 to be. 



' P.Z.S. 1876, p. 61. 



