No. 1.] ANT-LIKE SPIDERS OF THE FAMILY ATTW.F.. 7 



rated regions that they I'cach their greatest development of 

 genera and species; they are very much more numerous in 

 South America and in the Malay Archipelago than in any 

 other countries. The only suggestion that we can ofter in 

 explanation of this uneven distribution is that the tropics 

 abov;nd in small spider-eating birds, and that the mimetic form 

 is hei'e of the greatest value in enabling the little spiders to 

 escape from the birds under the guise of ants. 



In the following paper we have used twenty genera, of 

 which fourteen are new. As the clypeus, falces and legs vary 

 considerably in the species of one genus, and even in the sexes 

 of one species, we have thought it best to base our classifica- 

 tion mainljr on the general form of the cephalothorax, and on 

 the size and disposition of the eyes. 



AVe wish to acknowledge our indebtedness to the well- 

 known traveler, Mr. Herbert H. Smith, for the u.se of his valu- 

 able collection of South American Attidse ; to Mr. Eugen Simon, 

 for many interesting specimens from Ceylon, Luzon and other 

 places; and to Mr. .J. H. Emerton, for several figures of ant- 

 like Attidse which he has placed at our disposal. Our illustra- 

 tions are all from nature, bj'^ the skillful hand of Mr. Emerton. 



