YUCCA MOTH AND YUCCA POLLINATION. 131 
which belong to Pronuba); in the pupa (e) among other 
differences, lacking the series of dorsal spade-like projec- 
tions; in the form of the claspers in the male moth (Fig. 
3, f, 9); in the much stouter and differently shaped ovi- 
positor of the female (Fig. 3, 4, d); and especially in her 
lacking the maxiilary tentacles. 
Who, studying these two species in all their characters 
and bearing, can fail to conclude that, notwithstanding the 
essential differences that distinguish them not only speci- 
fically but generically, they have had a common ancestral 
origin? Pronuba, depending for existence on the pollination 
of the flower, is profoundly modified in the female sex in 
adaptation to the peculiar function of pollination. Pro- 
doxus, dwelling in the flesh of the fruit or in the flower- 
stem, and only indirectly depending upon the fructification 
of the plant, is not so modified, but has the ordinary char- 
acters of the family in both sexes. In the former, the larva 
quits the capsules and burrows in the ground; it has legs 
to aid it in its work, while the chrysalis is likewise beauti- 
fully modified to adapt it to prying through the ground and 
mounting to the surface. The latter, on the contrary — never 
quitting the stem — has no legs in the larva state, and in the 
chrysalis state is more particularly adapted, by the promi- 
nence of the capital projection, to piercing the slight covering 
of the stem left ungnawed by the larva. The former is very 
regular in its appearance as a moth at the time of the flow- 
ering of the Yuccas in their native range. The latter ap- 
pears earlier, as the food of its larva is earlier ready, and 
the female could not oviposit in the riper stem. 
