Spiders and Their Near Relatives 



Genus UROPLECTES (U-ro-plec'tes) 



This genus is the only representative in our fauna of the sub- 

 family Buthinae, which is characterized by the presence of a tarsal 

 spur at the distal end of the first tarsal segment of the third 

 and fourth legs. Of this genus the following species is the only 

 one yet found within the limits of the United States. 



The Mexican Uroplectes, Uroplectes mexicanus (U. mex-i- 

 ca'nus). — This is a pale species. There is no spine under the 

 sting; the teeth on the finger of the palpus are in 

 many oblique rows, with stouter teeth at the end of 

 each and to one side; there are from thirty to thirty- 

 five teeth in the combs; and the keels on the under 

 side of the last caudal segment are very strongly 

 toothed. This species has been found in Texas and 

 in California. 



Genus ISOMETRUS (I-som'e-trus) 



In this genus, there are only a few oblique rows 

 of teeth on the edge of the fingers of the chelae 

 and these do not overlap (Fig. 28); there is a large 

 spine under the sting (Fig. 29); and the abdomen 

 has a single keel above. The following is our only 

 species. 



The spotted Isometrus, Isometrus maculatus (I. 

 mac-u-Ia'tus). — This is a dirty yellow species marbled 

 and flecked with black. The body is thin and 

 In the female the postabdomen is 



usually about as long as the rest of the 



body; in the male, it is often twice as long. 



The hand is long and thin, thinner than the 



tibia of the pedipalp; the finger is from one and 



a half to two times as long as the hand. The 



combs have from seventeen to nineteen teeth. 



to nearly two inches in length; the males, to nearly three inches. 

 This species is distributed throughout the tropical and 



subtropical regions of the world; in this country it is found in 



southern Florida, and California, and, probably, in the inter- 

 mediate regions. 



26 



Fig. 28. 

 FINGER 

 OF ISO- 

 METRUS 

 MACU- 

 LATUS 



slender. 



Fig. 29. STING OF 

 ISOMETRUS MACU- 

 LATUS 



The female grows 



