130 MISSOURI BOTANICAL GARDEN, 
1, a) possesses no legs whatever, and eats but a small 
part of the stem (P1.39, Fig 1, f) preparing in the autumn, 
for hibernation, a cocoon of white silk which is covered 
on the outside with its castings and which remains pro- 
tected within the stem. Before making this cocoon, how- 
ever, it generally eats a passage-way to the outer covering 
of the stem and lines this with silk, leaving but a very thin 
cap (g). The chrysalis is formed in the spring, and when 
about to give forth the moth, pushes its way out through 
this cap. This happens almost always toward evening and 
the moth escapes just as the shades of night help to shield 
it during its more helpless hours, from detection. 
Various species of the genus Prodoxus are found asso- 
ciated with the different species of Yucca, breeding either in 
the flower stems, the main stalk, or sometimes in the fruit, 
and they will be considered more in detail, in the second part 
of this article. It suffices here to state that Prodoxus de- 
etpiens is the only species thus far found east of the Rocky 
Mountains ; that while it is quite constant in coloration east 
of the Mississippi, it is often more or less spotted with 
black in Colorado and South Texas, and that it shows the 
same tendency to retardation in development already no- 
ticed in Pronuba, some larve remaining in the stems two, 
tiree or four years. 
Where the stems are allowed to remain on the plant this 
Prodoxus becomes exceedingly abundant, and the stems are, 
when one year old, often seen to be riddled with the per- 
forations which the chrysalis made in issuing, and this is 
especially true of Y. angustifolia. 
Where the stems are cut, as they ordinarily are, in our 
gardens, soon after flowering, the larve are apt to be de- 
stroyed, so that the species becomes scarce. 
To recapitulate, the figures on Plate 39, will sufficiently 
indicate the structural details of Prodoxus decipiens and 
give emphasis to the differences which I have already 
pointed out between it and Pronuba yuccasella, in the larva 
(Fig. 1 @) being apodal (lacking even the thoracic legs 
