396 PROCEEDINGS OF THE ACADEMY OF [June, 



four pairs are present on each tibia), and armed distad with three 

 pairs of well developed spurs, the dorso-internal longer than any of 

 the other distal spurs. Caudal metatarsus non-sulcate and unarmed 

 dorsad, the distal extremity armed on both sides with long spines, 

 of which the internal is much the longer, and above these are situated 

 two minute teeth. 



Morphological Notes. — In the present genus the spines and spurs 

 of the caudal tibiae are extremely interesting. 



In the study of the North American species Mr. A. N. Caudell 

 first pointed out to the author a character in the distal spurs of the 

 caudal tibiae which proves to be absolutely constant and of the 

 greatest value. In four groups of North American species the internal 

 disto-ventral spur is much longer than the external disto-ventral 

 spur, in the remaining group these spurs are exactly equal in length. 



In the males of all of the North American species the proximo- 

 internal spine of the caudal tibia is highly specialized in structure. 

 It differs from the other spines in being very short, large at the base, 

 irregularly conical, suddenly attenuate and soft to the immediate 

 apex which is sharply pointed. The enlarged base is hard, of dark 

 color and polished, the soft portion is light in color and somewhat 

 translucent, while the immediate apex is hard and rather dark in 

 color. Frequently the hard apex is missing, and in such cases there 

 is every indication that it has been broken off. PanteP has carefully 

 discussed this peculiar specialization in his interesting morphological 

 studies in the present genus, and it has been casually noted in certain 

 species by other authors." 



We find other interesting characters in the spines of the caudal 

 tibiae of the North American species of the genus. In all of the 

 species having the disto-ventral spurs unequal in length the spines 

 (with the exception of the proximo-internal spine in the males, 

 which we have discussed above) are above rounded and hairy, below 

 concave with the margins of this sulcation minutely serrulate. In 

 all of the species having the disto-ventral spurs equal in length, the 

 disto-internal spine in the males is somewhat swollen near its base 

 and its shaft is appreciably bent; the other spines (likewise with 

 the exception of the proximo-internal spine in the males) are above 

 rounded and hairy, below concave, but with the margins of this 

 sulcation smooth. The apices of all of the spurs and spines of the 



1 Anal. Soc. Esp. Hist. Nat., XXV, p. 47, 1896. 



2 Saussure, Melarig. Orth., II, Fasc. V, p. 267, pi. 11, fig. VII, 6i, 1877. Brunner, 

 Prodr. Europ. Orth., p. 424, 1882. 



