March, i9i6.] Hebard : Genus Stenopelmatus. 73 



A. Size medium to very large. Occiput normally unicolorous. never heavily 

 banded. 



B. Size medium to large. Head less elongate, megacephalism fre- 

 quently striking. Caudal limbs proportionately shorter. Caudal 

 tibiae broadening regularly without well-defined distal point of 

 greatest width ; dorsal margins normally armed with three ex- 

 ternal and five internal spines, none being deflexed and the 

 more distal being usually longest ; longest distal spur much 

 shorten than, to nearly as long as, the metatarsus. 



fuscus Haldeman. 

 BB. Size medium large to very large. Head more elongate, megacepha- 

 lism not pronounced. Caudal limbs proportionately longer. 

 Caudal tibiae not broadening in male, broadening distad with 

 well-defined point of greatest width in female ; dorsal margins 

 normally armed with two external and five internal spines, the 

 broadening of the limb in the female causing the second ex- 

 ternal and fourth and fifth internal spines to be deflexed, the 

 external and fifth internal spines being usually decidedly the 

 smallest in both sexes ; longest distal spur -nearly as long as, 



to much longer than, the metatarsus longispina Brunner. 



AA. Size small. Occiput heavily marked with broad dark longitudinal bands. 

 (Pronotum normally narrowing but little caudad. Caudal tibiae show- 

 ing a greatly modified development of the condition found in longi- 

 spina; dorsal margins normally armed with two external and three 

 internal spines ; longest distal spur distinctly shorter than, to nearly 

 as long as, the metatarsus) pictus Scudder. 



In tising this key it is necessary to understand ftilly the difficulties 

 presented by these species, these are considered both in the introduc- 

 tion and further discussed under each species in the present study. 

 As we have remarked in other generic studies, no single character 

 can be relied on for specific determinations. This is particularly true 

 in the present genus, in which an unusual complexity of features is 

 encountered. Differences in the number of caudal tibial spines, or 

 slight variations in their position and relative length, are certainly 

 unworthy of specific distinction; much of the past synonymy being 

 mainly due to overestimation of the importance of variations in these 

 features. 



In addition to over 50 specimens previously recorded and some 

 40 now before us with insufficient data, all of which have been exam- 

 ined, we here record 195 specimens of the genus. 



