]66 BULLETIN 15 7, V. S. NATIONAL MUSEUM 



in the cracks of the bark, or other protected places. The color of the pupa Is 

 such that on an oak it would be almost indistinguishable. 



The food plant referred to is SisyTrhbriwrn thatianum; but Mr. 

 Schonborn also found the eggs on the common wintercress {Bar- 

 harea vulgaris). He never found more than one egg on a plant. 



In the females the apical portion of the fore wings in the area 

 which, in the males is orange is sometimes distinctly grayish and 

 rarely a more or less bright yellow. I have a female taken in the 

 woods along Paint Branch on April 29, 1931, in which the wing tips 

 are bright yellow. 



Genus PIERIS Schrank 



PIERIS PROTODICE (Boisduval and Le Conte) 



Checkebed White 

 Plate 29, Figures 5 to 8 



Occui^ence. — Formerly abundant, but now only of casual and ir- 

 regular occurrence. As this butterfly is often very local, it is possi- 

 ble that it may occur permanently in small numbers in some very 

 limited area or areas within or very near the District. I have seen 

 and taken it on the shores of Chesapeake Bay in Maryland in years 

 when it was not found in the District. 



Dr. L. O. Howard writes me that he never saw this species before 

 he came to Washington in November, 1878. In the summer of 1879 

 he noticed it very frequently around Washington. In a note in 

 Insect Life published in November, 1892 (vol. 5, no. 2, p. 99) he said 

 that about Washington " both the native and imported species of 

 Pieris are very destructive to Cabbage." In July, 1892, in company 

 with Dr. E. A. Schwarz, he had been investigating cabbage worms 

 on Col. John Rives's farm at Rives Station, Md., a station on the 

 Baltimore & Ohio Railroad 9 or 10 miles from Washington, and 

 this note was published in connection with his observations at that 

 time. 



Since then this butterfly has almost completely disappeared from 

 this region, having been unable here as elsewhere to compete with 

 the European P. rapae. 



There are two specimens, a male and a female without dates, in 

 the Schonborn collection, and the National Museum contains two 

 females, one taken in Washington on August 2, 1906 (I. J. Condit) , 

 and the other taken on July 18, 1919. 



In 1926 I took this species in the meadows beyond Cabin John on 

 September 6, saw it on September 13 in the same place, and noticed 

 it in the Smithsonian Institution grounds on September 10, In the 

 same month one was reported from the street in front of the Central 



