REHN AND HEBARD 241 



under M. c. californica, Del Monte material is practically inter- 

 mediate between the two subspecies. 



Biological Notes. — The Tamalpaisan form frequents the thick, 

 low chaparral from 1100 to loOO feet elevation and the heavier, 

 more arborescent chaparral from 1500 feet to the summit (2586 

 feet) of Mount Tamalpais (see plate XV, fig. 2). The principal 

 components of this chaparral are chamisal {Adenostonia fa.sci- 

 culatum) and manzanita (Ardostaphylos glandulosa), on ])Oth of 

 which Morsea occurs as commonly and as vigorous and active 

 as in southern California. The majority of those taken were 

 beaten at 2400 feet. From the data ])efore us it would be fair 

 to assume that the first individuals reach maturity some time 

 before August 17, the earlier of the two dates represented, and 

 also that the form persists well into September at least, as 

 immature specimens were taken on August 23. 



Morphological Notes. — This race exhibits form variation much 

 of the same character as found in typical californica. When seen 

 from the dorsum the fastigium varies quite appreciably in width 

 and in relative degree of production. There is a considerable 

 amount of variation in the antennal length and also in the degree 

 of spatulation and acuteness of the apex. 



Remarks. — We have discussed under M. c. californica the in- 

 tergradation of the present race and the typical form of the 

 species, as demonstrated by the Del Monte series. The present 

 northwestern extreme development of the genus is clearly a 

 derivative from M. c. californica, its intergradation with the 

 latter, its geographic position at the periphery of the generic 

 distribution and away from the center of development of the 

 subfamily in America, and also from the optimum development 

 of the specific entity, make its origin apparent. 



Specimens Examined: 63; 39 cf, 12 9, 12 immature 9. 



California: Mount Tamalpais, Marin County, elevation 1100-2,586 feet, 

 VIII, 17, 1909, (R. & H.; in chaparral of chamisal and manzanita), 286", 10 9 , 

 8 immature 9 : elevation 1500-2100, VIII, 23, 1907, (H.; on chamisal and 

 manzanita), llcT, 2 9 , 4 immature 9 , type, allotype and paratypes, [Hebard 

 Cln. and A. N. S. P.]. 



TRANS. AM. ENT. SOC, XLIV. 



