14 BULLETIN 124, U. S. DEPARTMENT OF AGRICULTURE. 
ceived at Hanover in strong active condition on June 10. She began to lay on 
June 11 and continued until June 22. Her 420 adult offspring represent only 
a part of her caterpillar progeny, for, besides the loss through disease and acci- 
dent. 15 pupae succumbed to excessive cold and other unfavorable conditions 
in a refrigerator while undergoing an experiment to determine the effect 
of cold upon color. Probably 500 eggs were laid. 
The proportion of males to females in Arizona is about 2 to 1. 
but Gerould. in Xew Hampshire, finds them about equal. In the 
field at Tempe one will always be impressed with the superabundance 
of males. This difference in the proportion of the sexes as between 
Arizona and New Hampshire is probably due to the fact that in 
Arizona the intestinal disease kills a large number of the larva? ; and 
since males develop a few days sooner than females, it is likely 
that the majority of the larvae killed would have developed into 
females, while those escaping the disease become males. In Xew 
Hampshire Prof. G-erould is often able to rear over 90 per cent from 
egg to adult in confinement, while at Tempe it is rare that 25 per 
cent of the eggs are reared. In a blooming alfalfa field the per- 
centage of males to females is still higher, owing to the fact that fe- 
males after feeding and mating leave this older alfalfa to seek new 
growth. In searching out this tender growth for egg deposition it 
seems as if they knew that if their eggs were laid on the older 
alfalfa it might be cut before the larvae could mature. One can tell 
at a glance an ovipositing female. She has a hesitating flight and at 
intervals will drop down for a moment on an alfalfa leaf and. de- 
positing an egg. will flutter on. soon repeating the operation and de- 
positing as many as four or five eggs per minute. 
Among the yellow butterflies in a field one notices many white or 
albino forms. These are of the same species as the yellow ones 
and. according to Prof. Gerould. 1 are merely color phases, as he has 
shown to be the case in Eurymus philodice (Godart). 
FEEDING HABITS OF THE BUTTERFLIES. 
The butterflies of Eurymus eury theme feed upon nectar from the 
blossoms of a great many plants. Over a blooming alfalfa field one 
can often see them by the millions, visiting the blossoms and extract- 
ing the nectar therefrom. This habit has occasioned many remarks, 
farmers quite often being under the impression that these butterflies 
were producing some direct results upon the growth of the alfalfa 
crop. The bee-keeping farmer usually insists that they are robbing 
his bees by taking nectar that belongs to them. In Circular 133 of 
the Bureau of Entomology, published in 1910. the writer ventured 
the remark, since he had witnessed the tripping of the pollen trigger 
1 Gerould, J. H. The inheritance of polymorphism and sex in CoUas philodice. Amer. 
Nat., v. 45, p. 257-2S3, May. 1911. 
