20 



NORTH AMERICAN BUTTERFLIES. 



and the hind wings have a line of dusky, triangular spots on the outer 

 border. Expands 2.50 to 3.00. Habitat, Southern States. 



31. PIERIS BECKERII Edw. 

 Becker's White Butterfly. 



size, small; wings, thin. Color, white, marked in male, on apex 

 of upper side of fore wings with about eight spots of dusky in two rows, 

 one marginal and the other within this. There is a spot in end of cen- 

 tral cell, containing a dash of white. No markings on hind wings above. 

 Beneath, the markings of fore wings are repeated but enlarged, and 

 there is an extra spot on the middle of the lower margin. The veins 

 of hind wings are broadly margined ( less so on lower branch of upper 

 vein) with dusky scales that are tmged with greenish and orange, and 

 these show a tendency to become fused near the outer border, and form 

 a sub-marginal band, Fig. 11, e. Female, similar but there are two 

 extra spots on fore wings, one to each row, forming bands nearly across 

 the wings. The dusky veinings on hind wmgs, seen below, show more 

 faintly above, and there is a marginal, and a partial sub-marginal row 

 of spots. Below, similar to male. Expands 1.6."> to 2.00. 



Habitat, Nevada, Utah, Oregon, California, Washington Territory, 

 Colorado, and Arizona. 



Fis. 11. 



Illustrating the genus Pieris, a, rapae, tip of fore wing, upper side; b, napi same; c, sisynibri, 

 lower side, hind wing ; e, beclcerii, same; d, protodice, (female) upper side offore wing; f, ilaire, 

 apex) upper side fore wing. 



32. PIERIS SISYMBRIBd. 

 California White Butterfly. 

 Similar to P. beckerii but is smaller, with the markings on upper 

 side of fore wings more extended, and square or rectangular, not trian- 

 gular; the markings on the lower portion of hind wings are also darker, 

 and the fused sub-marginal band is nearly black, forming arrow-shaped 

 marks, Fig, 11, c. Expands 1.30 to 1.60. Habitat, California, Neva- 

 da, Colorado, and Arizona, 



