Attidiv of XortJi America. 5 



T. Thorell: Spiders of Colorado, Bull, of Hayden".s U. S. Survey of the 



Territories. 

 E. Keyserling: Neue Spinnen aus Amerika, VI. 

 H. C. McCooK: Proc. Acad. Nat. Sci. of Philadelphia, 1883. 

 Peckham: Descr. new or little known Attidae, 1883. 



The Attida? have usually a high cephalothorax with almost vertical sides, 

 and short and thick extremities, althougli there are many exceptions. Per- 

 haps the position and relative size of the eyes — in which they most nearly 

 approach the Lycosidas — is of most value in defining the family. The 

 eyes are arranged in three or four transverse rows, three in the sub-family 

 Attinse and four in the sub-family Lyssomana?. In the former the first 

 row is composed of four eyes, the middle ones being the largest; the second 

 row is composed of two very small eyes, and the third of two of medium 

 size. In the Lyssomanae, the two outer eyes of the first row are placed so 

 far back as to divide it into two transverse rows; otherwise the eyes are 

 alike. The spiders ai-e, many of them, very brilliantly colored — as much so 

 as are the humming birds or beetles. As the markings are commonly 

 formed of colored hairs or scales, they change considerably when the spider 

 is wet, and are moreover, very easily rubbed off. The entire appearance of 

 a spider may thus be changed, and its identification rendered difiicult, if 

 not impossible. The Attidee, like the birds, moult frequently, and at each 

 moult the markings may change, so that some of the older writers have 

 formed several species for the different moults of one. These difficulties are 

 increased by the fact that the adult males and females of a species usually 

 differ considerably in appearance. 



Although a great many species have been described, we have been able to 

 identify but a limited number. The Attida^ live on the ground, on plants, 

 and on trees, jumping on their prey. They form no web, but generally at- 

 tach a fine when they jump, to save themselve in case they miss their aim. 

 The females place the cocoon under leaves or bark and spin some cross lines, 

 under which they stand until the eggs are hatched. 



Of the fifty-five species described by Hentz, we have identified forty-five. 

 Of the ten remaining, probably five or six are varieties of those that we 

 liave described, but this being uncertain, we have not included them. 



The key which follows is useful only in determining the species described 

 in tliis i^aper: 



Key to Genera of North American Attid.e. 



1 . Eyes in four rows Lyssomaxes. 



2. Eyes in three rows 3 



3. Body slender, ant-like, legs weak 5 



4. Body not slender nor ant-like 9 



5. Ceplialir part higlier than thoracic; lip much longer tlian wide 



Salticus. 



6. Cephalic part not liigher than thoracic: lip as wide as long 7 



