38 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Dhujraui shoicing distribution. 



" QuadricolHft. — Sonora, Mexico. In the Biologia Cent. America (Vol. IV, Pt. 1, p. 

 80) the author writes that he had seen specimens from Mexico. They probably belonKcd 

 to a race or a closely related species. I have not seen an authentic example from Lower 

 California. .V specimen so given by Dr. George Horn — and examined by me — is probably 

 a closely related species (Proc. Cal. Acad. Sciences, 2d ser., IV, Pt. 1, p. ;!50). The 

 specimen was anatomically defective and has since been destroyed. 



>> Humeralis. — Mexico ? In the Biologia (reference as above) the author writes: 

 " There is an example of this species in Mr. F. Bates's collection labeled as from Mexico ; 

 possibly some mistake about the locality." I agree with this. 



Dr. George Horn, in llio Proc. Cal. .Vcad. Sciences, 2d ser., IV, Pt. 1, p. 350, gives this 

 species as occurring at Sierra Laguna. San Francisquito, La Chuparosa, and San Jose del 

 Cabo, Lower California. I have studied these specimens in the collection of the academy 

 and lind (hem not huincralis at all. (See tihiaUs.) 



Genealogy. — In the iiecomprtnying diagram I have presented my 

 present views regarding the descent and rehitionsliip.s of the species 

 and races of the subgenus Melaneleode.s. 



From the subgeneric trunk divergence occurred along the lines of 

 Groups I and II. 



In Group I the principal divergence is manifest in the calcarine 

 development as set foi'th for the Carhonarla and Quailricollis sec- 

 tions. 



In the QiiadrieoUis section the calcarine modification is most 

 strongly perpetuated, the specific dill'erentiation resulting in the mod- 

 ification of surface sculpturing, cuneaticollis being intermediate be- 

 tween (jiKidricolIis and lun/icra/is, but retaining greater affinity with 



