373 
have found Prodoxus larvie in the stems of all other Yuceas which I 
have been able to examine, and doubt- 
less a number of other species are yet 
to be discovered and characterized. 
The species so far known are inter- 
esting in that they illustrate in a re- 
markable manner what I have called 
fortuitous variation, or superficial 
colorational characters; also a great 
tendency to graduate into each other 
by variations among themselves, not 
only in the structure of the ovipositor 16. 72.—PRopoxvs MareinaTus: a, anal ab- 
: . C : dominal joint of female — X 26; b7 o, basal 
and the male genitalia, butin the wing ging of ovipositor; tj 0, terminal joint 
markings. The time to which these — o.; ov, oviduct; ¢, claspers of male from 
remarks are limited will prevent going i See XT OR ee 
into descriptive details, and [I content 
myself with illustrating, in this connection, a few of the more distinctly 
marked species (Figs. 72, 73, 74, and 75). The genus interests us most, 
however, in indicating how 
Pronuba, with all her abnor- 
mal peculiarities, has been 
evolved; for though we have 
striking differences in habit 
and mode of development of 
larva, pupa, and imago, be- 
tween Pronuba and Prodoxus,. 
yet the affinities are equally 
Fie. 73.—PRODOXUS EO RaSuS: a, left eoiatt wing, striking, and the two genera 
hair-line underneath showing natural size; b, geni- : : : 
talia of male, dorsal view — X 14; c, do., lateral exemplify, mm an exceptional 
view — X 18; d, anal joint of female with ovipositor degree, the power of natural 
ee aca ee nisclectionoty intensify habits. 
and structures in opposing di- 
rections according to the requirements of the species. Prodoxus is. 
practically dependent upon Pronuba, for if the latter did not fructify 
the plant the former would in time have no flower-stems to breed in, 
and while Prodoxus has gone on generation after generation, with com- 
paratively little change, Pronuba has become profoundly specialized to 
fit it for a more specific purpose. 
CAPRIFICATION OF THE FIG. 
It was my purpose here to explain to you some interesting facts as to 
the caprification of the fig, and the remarkable structural peculiarities 
and influence of the caprifig insects. It is, however, a somewhat com- 
plicated subject, and I could not, within the time allotted to me, do jus- 
tice both to it and the matter of Yucca pollination. As an indication, 
