No. 461] NORTH AMERICAN INVERTEBRATES. 321 
Tibia I with 3-3 spines (or less), the basal one of inner series situate 
one third of tibial length (or greater suse from base; coxa I usually 
widely separate . ; i 42. 
12. Metatarsus IV heavily igit d near base and middle, both below and 
on sides; cephalothorax never very low, nor very broad ; ar spines 
on patelle III and I 
Metatarsus IV spined only at tip, or "with one or two sieh spines on 
sides; never a basal and middle circle of spine s. 
13. Coxe I approximate; leg I plainly dickendd: sternum usually long ; 
usually large species 1 15. 
Coxe I widely xn: fu I ‘barely dele ened sternum short; very 
small species, with a narrower cephalothorax 14. 
14. Ocular area occupying nearly one half of bepiodpttóters as wide i in 
front as behind, dorsal eyes as large as laterals of first row ; no spines 
below on tarsus IV. eon. 
Ocular area less than one half of euplalo gota, rather wider behind ; 
dorsal eyes smaller than laterals of first row ; spines below on tarsus IV 
Attidops. 
15. Abdomen about four times as = as broad; tibia I with 4-4 spines 
below . $ i ; i en 
16. 
Abdomen ndi shortit 
16. Eye-region occupying two “fifths of Kepler the sternum nearly 
as broad as long, smaller species Fuentes. 
Eye-region occupies about one third of cephalothorax the sternum 
much longer than broad ; larger species : —— 
17. Tibia I with 4-4 spines below 
Tibia I with less than 4-4 spines buius 19. 
18. Ocular area N narrower behind die in p nh: lc IV plainly 
Mevia. 
longer than I 
Plexippus. 
Ocular area barely narrower behind; ‘les I as long as IV 
19. Cephalothorax rather prd N occupying "€ one third 2 
length; tibia I with 3-3 spine 
Cephalothorax p gea ai fully two fifths ot ed; 
coxa I widely separa 
20. Basal spine of ipa I saa IV 
abdomen vittate 
Basal spine of tau Hl and Iv biuch denkt; abd 
about: one half as ong as the joint ; 
Phlegra. 
omen not vittate 
* Sidusa. 
21. Patella III as long as IV, no patellar spines e 
Patella III shorter than IV, patellar spines pres "s. 
22. Cephalic part about two thirds of cane reaching almost to 
I thickened ; hind metatarsi spined only at tip 
abdomen ; legs short, leg I thi mn 
1 Attidops, a new genus for Ballus youngi Peck. 
