1916.] NATURAL SCIENCES OF PHILADELPHIA. 133 



merit of the present type, which race is founded merely on an inten- 

 sification of the characters which constitute the race N. c. arcuatus. 



This geographic race is known only from central and southern 

 Florida, in the northern portion of its range gradually intergrading 

 with -V. c. arcuatus. 



Acrydium arenosum arenosum (Burmeister). 



North Carolina. Waycross, V, 8, 1911, 19, [Ga. St. 



Charlotte, VII, 27, 1913, (R. & H.), Billy's Island, VI, 1912, (J. C. Brad- 



:; ', 2 9, 1 juv. <?, 1 juv. 9. ley), 1 d". 



Wnghtsville, IX. 7, 1911, (R. & H.), Mi xon 's Hammock, Okeefenokee 



1 1 d\ 19,3 juv. Swamp, V, 16, 1915, (H.), 10 o" , 6 9 . 



Lak. \\ a.vamaw, IX, S, 1911, (R. & Spring Creek, VI, 7-23, 1911; VII, 



H.), 10 cf, 9 9, 4 juv. 16-29, 1912, (J. C. Bradley), 2 <f, 



4- 

 Georgia. 



Vicinity of Stone Mountain, VIII, 3, 



1913, (R. & H.), 1 <?. Jacksonville, (T. J. Priddev), 1 cf, 



Vienna, VI, 5, 1910, 2 o\ 2 9, [Ga. [Hebard Cln.]. 



St. Cln.].' 



Of this series but three of the adults are of the strongly abbreviate 

 pronotum phase, namely, a male from Lake Waccamaw, one from 

 Mixon's Hammock and the single Jacksonville specimen. All of the 

 other individuals have a more or less distinctly caudate pronotum. 

 In coloration we have five principal unit types of pattern, all varying 

 individually in tone and also in degree of combination. A large per- 

 centage of the specimens are of a uniform coloration of variable tone 

 without markings. 



From a study of the available material of this species group, it is 

 evident that A. arenosum, angustum and blatchleyi are merely geo- 

 graphic races, limited to definite areas and probably grading into 

 one another in equally definite areas. We have not evidence enough 

 to demonstrate this in regard to blatchleyi, but that it is merely an 

 exaggeration of the arenosum type is evident from an examination 

 of a female from Deep Lake, Florida, clearly referable to blatchleyi. 

 The intergradation of arenosum and angustum, however, is well estab- 

 lished by our material, specimens from Raleigh, North Carolina, pre- 

 viously referred by us to obscurum ( = angustum), 23 being intermediate 

 in character. The principal differences between the two forms have 

 already been set forth by Hancock, the more rugose and striate char- 

 acter of the dorsum of the pronotum of a. arenosum, however, being 

 more evident than any of the other differential features. 



From the evidence in hand we find that A . arenosum arenosum does 



m Proc. Acad. Xat. Sci. Phila., 1910, p. 022, (1911). 

 10 



