1896.] SPIDEES FEOM ftttU tOWEB AitAgONfe. "/Sl 



of the lateral posteriors and 1| a transverse diameter of the 

 former from them. Taking another character — the spinulation 

 of tibia i. : in some of these examples there are no spines, in 

 some 1, in others 2 or 3 ; while in one case, tibia i. left side had 

 2 spines, tibia i. right side had none. The central anterior eyes 

 are sometimes 2, sometimes 3 diameters apart ; while the lateral 

 anteriors vary greatly in their distance from the margin of the 

 clypeus, in the immature being quite close '. 



Given, however, -plenly of examples of each form, I have no 

 doubt but that certain characters might be tabulated which would 

 be broadly trite of the various forms, but only then to be used with 

 caution. 



Of the three forms — A. Jiartii, A. crassipes, and A. wallacei — of 

 which I have been able to compare the actual types, the form of the 

 cephalic area furnishes a good differential character, while the spinu- 

 lation of tibia i. furnishes another, and the form of the sternum a 

 third. But of these species I have seen only five examples (females) 

 of A. Jiarli.i and one (female) of yl. crassipes. I venture to think 

 that no satisfactory conclusions will be arrived at until anichno- 

 logists are willing to liaud over all available material of a particular 

 -genus to some one or other who is prepared to take the trouble to 

 thoroughly compare every specimen and tabulate tlie characters. 

 At present there is confusion of tongues and hair-splitting dispu- 

 tation concerning the fraction of a difference in the distance 

 between particular eyes, whereas the examination of a long series 

 usually proves that these same disputed distances are themselves 

 constantly variable quantities in the same form. 



The table given below will probably need considerable modifica- 

 tion when a long series of forms is subjected to examination. 



A. Tibia i. with a series of 5-13 spines on inner side. 



1. Anterior row of eyes a little wider than posterior.. A. caraiba, Sim. 



2. Anterior row of eyes not wider than posterior. 



a. Tibia i. with 5-6 spines on inner side ; tibia ii. 



without spines on inner side A. scahps, Sim. 



b. Tibia i. with 9-13 spines on inner side ; tibia ii. 



with 1-3 spines on inner side A. hartii, Poo. 



B. Tibia i. without any spines, or with 1-3 only on inner 



side. 



I. Central posteriors smaller than laterals. 



1. Central posteriors scarcely smaller than laterals, 



a. Tibia i. wi(,h three small spines on inner side. A. crassipes, Keys. 



b. Tibia 1. without any spines on inner side A. rojasi, Sim. 



2. Central posteriors much smaller than laterals... A. valencianus, Sim. 



II. Central posteriors reuiform, larger than laterals . A. wallacei, mihi. 



The characters of A. Jiartii and A. crassipes have been taken from 

 the types ; tlie characters of the other species are taken from 

 M. Simon's descriptions (Ann. Soc. Eut. Pr. 1889, pp. 176-177). 

 They must, however, be used with caution. 



' Mr. Pooock has observed similar differences in the characters at different 

 atages of A, hartii, Aim. Mag. Nat. Hist. ser. 6, xvi. p. 195. 



47* 



