GENUS PIERIS 93 



finer in the north near the National boundary than it is in the 

 southern warmer and drier regions. The peculiar greenish-black 

 markings on the underside of the hind wings are so peculiar and 

 distinctive that no one can mistake the species after having once 

 seen a specimen or a plate of it. 



I have observed Beckeri ovipositing on the desert plant Isom- 

 eris arborea, on the margin of the Colorado Desert in Southeast- 

 ern California. 



35. Pieris Sisymbri. 



Plate \' : Figures 35. a, b. c. 



Fig. 35, Male, Summit. Cal., 7.500 feet altitude. June 26, 

 1892 : Author. 



a, Male, underside, Summit, Cal., 7,500 feet altitude, 



June 26, 1892 ; Author. 



b, Female, Paso Robles, Cal., March 16, 1894 ; Author. 



c, Female, underside, Mt. St. Helena, Cal., April, 



1894 ; Author. 



On the West Coast Sisymbri flies from San Luis Obispo 

 County on the south to perhaps the northern line of the State of 

 California, and thence east through Nevada to Colorado, and 

 south to northern Arizona. It is rather a mountain butterfly, not 

 being found on the plains in any case, so far as I have observed, 

 but frequenting the hills and the higher mountains, up to at least 

 8,000 feet altitude. I have found it abundant enough in Central 

 California, but absent both in the north and the south. It has lieen 

 stated to be plentiful all over the State, but that is a mistake. It is 

 very peculiarly marked, but quite distinctively, when you become 

 acquainted with it. In life, the veins are not black, as has been 

 stated, but amber, or yellowish, and it is only after the lapse of 

 some years that the veins become black. 



Egg is long, narrow, conical, both base and top flattened, ribbed, 

 yellow when fresh, and later, just before hatching, red. From 

 egg to chrysalis is from thirty to thirty-three davs : the chrvsalis is 

 dark-brown ; the larvse moult but three times. 



36. Pieris Flava. Not elsewhere illustrated in accessible form. 



Plate V ; Figures 36, b, bb. 



Fig. 36, Female, given me by O. T. Baron, in 1879. ^^ 

 data. 



