670 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



Genus PRISTOCEUTHOPHILUS Rehn. 



Pristoceuthophilus Eehn, Trans. Amer. Ent. Soc, vol. 29, 1903, p. 17. 



This genus is a development of Ceuthophilus and its divergence 

 from that type is not sufficient to mark it a strongly characterized 

 genus. The main differentiating character is the development of the 

 fastigium of the vertex into a distinct acuteangulate homUke projec- 

 tion directed forward and more or less downward. An important 

 secondary sexual character is furnished by the dorsum of the abdomen 

 of the male, which is ornamented by several more or less elevated 

 tubercles or blunt spines, and sometimes with a few conspicuous 

 smooth elevated areas (fig. 15). The unique type of the genus, P. 

 rhoadsi of Rehn, an unique male from Mexico, has scarcely a trace 

 of any dorsal roughness and the yomig stages of all the species, even 

 those in which the dorsal armature is conspicuous in the adult, show 

 few or no dorsal tubercles or elevations, especially in the earlier instars. 



As a constant character in this genus, so far as known, is the inner 

 valves of the ovipositor being furnished apically beneath with more 

 or less rounded triangular serrations only, sometimes scarcely more 

 than undulations, and without an apical hook. In CeuthopMlus the 

 above is true only of immature specimens and of a portion only of the 

 species in the adult form, the rest having the ovipositor armed be- 

 neath with several more or less slender subapical teeth and furnished 

 at the tip with an apical hook. 



There are seven species now referred to Pristoceuthophilus and 

 other species now in CeuthopMlus may eventually be found to belong 

 here. But in this connection it is well to observe carefully the f as- 

 tigiimi of the vertex, the dorsal siu^ace of the abdomen in the male 

 and the ovipositor of adult females. If the vertex is smooth or fur- 

 nished only with a tubercle, if the abdomen of the male is smooth 

 above, or if the inner valves of the ovipositor of the adult is armed 

 below with a slender subapical tooth or furnished with an apical hook, 

 then the specimen is a CeuthopMlus. But if the vertex is developed 

 into a hornlike declivitous projection, the abdomen of the male fur- 

 nished above with tubercles or spines, or, usuaEy, if the ovipositor of 

 the adult female is unarmed beneath or furnished only with more or 

 less rounded serrations or undulations and without an apical hook, 

 then the specimen is a Pristoceuthophilus. 



KEY TO THE SPECIES OP PRISTOCEUTHOPHILUS (bascd 071 the male). 



1. Dorsal surface of the abdomen with tubercles or spines and also with some ele- 



vated smooth areas 2. 



Dorsal surface of the abdomen without elevated smooth areas 3. 



2. Dorsal surface of the abdomen with numerous rounded tubercles and four or 



five large elevated smooth areas, none of wliich are more tlian one-half as liigh; 

 as broad; cerci as in figures 13 or 14 celatus Scudder. 



