44 Annals of the Carnegie Museum. 



The specimens from Corumba are decidedly larger and more robust 

 than the others. They also differ in having longer and heavier hind 

 legs with much longer spines on the inner side of the hind tibia?, while 

 the crest of the pronotum is higher and more evenly arcuate than in 

 individuals examined from elsewhere. Specimens of the present 

 species have been examined by me from Central America, U. S. of 

 Colombia, Venezuela, British Guiana, Trinidad, Paraguay, Peru, and 

 Ecuador. 



Genus Alcamenes Stal. 

 Alcamenes Stal, Bihang Svensk. Akad. Handl., V, no. 4, pp. 14, 54 (1878). 



The genus Alcamenes Stal is strictly South American, and its repre- 

 sentatives are confined to southern Brazil, Paraguay, and northern 

 Argentina. Several distinct species are known. These insects are 

 rather closely related to the genus Prionolopha of the same author. 

 The annexed table will aid in the separation of the species so far 



as known: 



Synopsis of the Species of Alcamenes. 



A. Pronotum with the median carina tectiformly elevated. The posterior lobe 

 much longer than the anterior. 

 b. Anterior and middle sulci of the pronotum obsolete above. Tegmina twice 

 maculate. Hind tibiae twelve- to thirteen-spined in outer row. 



granulatus Stal. 

 bb. Anterior and middle sulci of the pronotum strongly impressed, cutting the 

 crest. Hind tibiae ten- to eleven-spined externally. 

 c. Tegmina not maculate. 



</. Tegmina lanceolate, one-half to three-fourths the length of the 



abdomen, the costal border only gently lobate. . .cristatits Bruner. 



dd. Tegmina acuminate, very short, not extending beyond the apex of 



second abdominal segment, the costal border very strongly lobate. 



lobipcnnis sp. nov. 

 cc. Tegmina at least faintly maculate, their hind border strongly arcuate 



and pale bordered brevipennis Giglio-Tos? 



A A. Pronotum with the crest only moderately elevated. The posterior lobe shorter 

 than the anterior one. 

 b. Body slender. The posterior sulcus of the pronotum a little more prominent 

 than the others. Hind margin obtuse. Hind femora slender. 



brevicollis Stal. 

 bb. Body robust. The posterior sulcus of the pronotum strongly impressed. 

 Hind margin a right angle. Hind femora tumid at base. 



clarazianiis Pictet et Saussure. 



