82 PROCEEDINGS OF THE ACADEMY OF [Mai'ch, 



longitudinal carina has no taxonomic significance. McNeill's 

 rostrata was based on individuals with the very acute fastigium, 

 but the extensive material now before us shows this condition to 

 be purely individual. 



Synonymy. — The synonymy given above is very evident to 

 anyone having before them the typical material of the "species," 

 or even topotypic males. Morse" and Rehn and Hebard'^ have 

 already established the synonymy of vigilans, which further study 

 has fully confirmed. McNeill's rostrata has been the subject of 

 considerable study, particularly as nearly topotypic material 

 showed- in part a more acute fastigial form than the average of 

 alacris. A careful analysis of the extensive series before us, cover- 

 ing the whole known range of alacris, shows clearly and most 

 convincingly that similarly very acute fastigii are found at prac- 

 tically every locality represented by a fair series, and also that 

 Oklahoma and north Texas material is as variable, in this respect, 

 as that from other regions. The variation in the Oklahoma and 

 Texas individuals embraces types with the fastigial angle as rounded 

 as in the more average eastern material. The whole range of 

 fastigial variation is similar to and co-extensive with that occurring 

 in all the other species of the genus. The other features given 

 as diagnostic of alacris and rostrata by McNeill are variable and 

 untrustworthy. That author had but five specimens of the two 

 "species" before him at the time, so there is little wonder he was 

 led to assign erroneous values. 



Measurements {in millimeters). 



cf Length of Length of Length of Length of 



body. pronotum. tegmen. caudal femur. 



New Berne, North CaroHna 35.3 6 28 22 



New Berne, North Carolina 37.2 6 26 20 



Southern Pines, North CaroHna 2S 4.8 20.8 17.4 



Southern Pines. North Carohna 34 5.4 25.2 19.6 



Winter Park, North Carolina 32.2 5.2 22.8 18 



Winter Park, North Carolina 37 5.7 25.7 21.2 



Seven Mile, South Carohna 36 6.1 26 21.2 



Seven Mile, South Carolina 39.4 6.5 26.7 21.2 



Groveland, Georgia 37 5.3 25.1 19.6 



Groveland, Georgia 39 5.6 27.3 22 



Bainbridge, Georgia 34 5.4 25 18.8 



Bainbridge, Georgia 37 5.4 26.5 19.5 



Jacksonville, Florida 35 5 24 19.5 



Jacksonville, Florida 36 6 27 20.5 



Pomona, Florida 36.2 6.1 26.5 20.9 



31 Carneg. Inst. Wash., Publ. No. 68, p. 27, (1907). 

 52Proc. Acad. Nat. Sci. Phila., 1916, p. 156, (1916). 



