104 MISSOURI BOTANICAL GARDEN. 
remains in different sized lumps on the inside of the per- 
janth, and cannot be introduced into the stigmatic tube 
without artificial aid. 
Our commoner garden Yuccas, forms of jilamentosa, 
depend on the commoner Yucca moth, Pronuba yuccasella 
(Pl. 34, Fig. 1, 6. c.) and so do all the different species 
found east of the Rocky Mountains, so far as we yet know. 
During the day-time we may, by knowing what and where 
to seek, often find this moth either singly or in pairs, 
resting with folded wings within the half-closed flowers. 
It is then not only hidden from ordinary view, but well 
protected by the imitative color of the front wings with that - 
of the flower, so that close scrutiny is necessary for its 
detection. If we visit the plant after 
co * * * the garish day 
Has sped on his wheels of light away ”’ 
and when, with full-blown perianth, the Yucca stands in 
all her queenly beauty, and sends forth her perfume more 
strongly upon the night air, we shall, with a little patience, 
meet with this same moth, flitting swiftly from flower to 
flower and from plant to plant —the dusky nature of the 
hind wings and of the undersurface of the front wings almost 
completely offsetting and neutralizing, when in motion, 
the upper silvery whiteness of the latter, and thus still 
rendering the insect a little difficult of detection. It is 
principally the male which we thus see flying and, by the 
aid of a ** bull’s eye,’’ we shall find the female for the most 
part busily at work in the flowers. He, with relatively 
stronger wing-power, can afford to spend in the most pleas- 
urable way the few brief days allotted to him; but she is 
charged with a double duty and loses little time in its per- 
formance. As a part of the maternal task of continuing 
her race, she must act as foster-mother to the plant in 
order to ensure a proper supply of food to her larvae, 
which, as we shall presently see, feed on its seeds. 
