1932 ] 
Observations on Pieris protodice 
85 
NOVEMBER OBSERVATIONS ON PIERIS PROTODICE 
VERNALIS EDW. IN MISSOURI (LEPID. PIERID^E) 
By Harold O’Byrne 
Webster Groves, Missouri 
The spring forms of some species of butterflies are occa- 
sionally seen in the fall. Scudder 1 says that the butter- 
flies of Pieris protodice Bdv. & Lee. appearing late in the 
fall approach in coloration the spring type, and he attributes 
this to the cool nights. Comstock 2 mentions a similar 
occurrence in Eurymus eurytheme Bdv. ; late fall individ- 
uals, presumably affected by the cold while in the pupal 
state, develop into the spring form autumnalis Ckll. instead 
of the summer form eriphyle Edw. 
A noteworthy instance of this occurred in November, 
1930, on the Ranken Estate near Valley Park, Missouri, 
when large numbers of Pieris protodice were seen, all of 
which had the coloration of the spring form vernalis Edw. 
Many of both sexes were observed on the mornings of No- 
vember 9th, 16th, and 23rd, and all of the butterflies seen 
on the three days were flying in one small area; the west 
slope of a small valley that was exposed to direct sunshine 
and protected from the wind. Random collecting showed 
that there were nearly equal numbers of both sexes on each 
day of observation ; nevertheless the eagerness of the males 
to mate caused them to cluster about the females as they 
were issuing from the pupae, and make unsuccessful at- 
tempts to mate with them, even though their wings had 
just begun to expand. Several pairs were found in coitu on 
stems just above the voided pupal skins of the females, 
whose newly inflated wings were still soft. 
Although the nights were chilly, this was an unusually 
mild November, and warm, sunny days continued nearly to 
the end of the month. If the coloration of the form vernalis 
is due to the effect of cold on the pupae, then the observed 
