16 NEW YORK STATE. MUSEUM 
Subdivisions of Pisauridae. Simon separated the Pisauridae into 
three rather ill-defined groups designated respectively the Pisaureae, 
Thalassieae and the Dolomedeae. The first embraced a considerable 
number of genera distinguished by having the median ocular area 
slightly longer than broad posteriorly and the tarsi generally pro- 
vided with an onychium. But in the three American genera 
included in Pisaureae, Pelopatis has this area broader posteriorly 
than long and in Thanatidius and Pisaurina the dimensions are about 
equal. 
In structure of the epigynum and palpus, closer agreement 1s 
found and upon these characters, rather than eye arrangement, sub- 
family distinctions may possibly be made. Based on the structure 
of the sexual organs, the genera named above would fall in one 
group and Dolomedes and possibly Thaumasia in a_ second; 
Thalassieae has no representatives in America north of Mexico. 
Key to the Genera of Pisauridae 
A Eyes in two rows; width of clypeus at least twice the diameter of an 
anterior median eye 
B Lower margin of the furrow of the chelicera with three teeth 
C Median ocular area about as wide posteriorly as long; teeth 
evenly spaced PISAURINA 
CC Median ocular area much wider posteriorly than long; two 
teeth close together, the third somewhat remote THAUMASIA 
BB Lower margin of the furrow of the chelicera with four teeth 
DOLOMEDES 
AA Eyes in 3 or 4 rows; clypeus narrow or obliterated 
B Line of anterior lateral eyes (first row) about equal in width to 
that of posterior median eyes (third row) THANATIDIUS 
BB Line of anterior lateral eyes (first row) much wider than that 
of posterior median eyes (third row) IP IBILOPZAN ITI 
THANATIDIUS (Simon) 
Hist. Nat. Araignées, 1898, 2:293 
Cephalothorax longer than broad, somewhat depressed; cephalic 
part up to posterior eyes, ascending; broad and flat behind posterior 
eyes to posterior declivity. yes in four rows, the total area not 
quite as long as broad posteriorly; line of anterior lateral eyes (first 
row) scarcely wider than line of posterior medium eyes (third row) ; - 
area outlined by four median eyes a little wider posteriorly than long; 
area of four anterior eyes considerably wider anteriorly than long; 
anterior lateral eyes on stout conical tubercles projecting from 
anterior margin of head. Lower margin of furrow of chelicera with 
three teeth. Abdomen long and slender. Legs 1-2-4-3; tibia of first 
and second legs beneath with 2-2-2-2 spines, apical pair reduced; 
metatarsi with 2-2-2-2 spines beneath, apical short. 
