Fig. 25. A COMB OF A SCORPION 



Fig. 26. TARSUS OF BUTHUS 



Spiders and Their Near Relatives 



The sclerite on the middle line of the body from which the 

 combs arise is termed the basal piece of the combs (Fig. 25); 

 the series of sclerites that form the front margin of a comb con- 

 stitute the marginal area; next to these there is a series of 



sclerites constituting the middle 

 area; the small sclerites be- 

 tween the middle area and the 

 teeth are the fulcra; and the 

 long slender appendages of the 

 comb are the teeth. 



The characters presented 

 by the tarsi of the legs, and especially of the last pair of legs, 

 are much used, as, for example, the presence or absence of tarsal 

 spurs and the number of these spurs when present. Sometimes 

 the last segment of a tarsus is 

 prolonged above the claws form- 

 ing a dorsal lobe (Fig. 26); and 

 sometimes this segment is pro- 

 longed into a lobe on each side, 

 the lateral lobes (Fig. 27) ; and there is often a more or less claw-like 

 empodium below and between the claws (Fig. 26). 



About a score of species of scorpions are known to occur 

 in the United States; besides these, other Mexican species may 



be found in southern Texas. A general work 



on the scorpions of the world was published 



by Kraepelin in 1899 and a synopsis of our 



species was published by Banks in 1900. 



The following account is based upon these 



two works and upon a study of the specimens 



in the collection of Cornell University. The most important 



work on the habits of scorpions is that of Fabre in the ninth 



series of his Souvenirs Entomologiques (1907). 



Kraepelin divides the order into six families; but only four 

 of these families occur in the United States; these can be separated 

 by the following table: 



TABLE OF FAMILIES OF SCORPIONS 



A. Only one spur at the base of the last tarsal segment of the 

 last pair of legs, and this is on the outside. P. 28. 



SCORPIONID/E 



Fig. 27. TARSUS OF 

 PANDINUS 



24 



