80 PLANTS AND ANIMALS 
A very remarkable instance of a different kind is 
supplied by the relations existing between the Ameri- 
can species of Yucca and the small white-winged 
moths of the genus Pronuba. The following succinct 
account is given by Professor G. H. Carpenter: * “The 
female of these moths has not only the palps of the 
first maxille developed, but the region of the maxille 
(palpiger) whence they spring produced into a pair 
of long, flexible, hairy processes. By means of these 
she collects from the anthers pollen, which she deliber- 
ately carries to the stigma to ensure fertilization. 
With her piercing ovipositor—a most abnormal 
development among moths—she bores through the 
tissue of the pistil, and by means of the flexible egg- 
tube, protrusible beyond the ovipositor, lays her eggs 
close to the ovules of the Yucca. The caterpillar 
when hatched feeds on the growing seed of the plant, 
which would never develop were it not for the action 
of the Pronuba moth. This action is most wonderful, 
in that the moth herself gets no benefit from it. Her 
food canal is degenerate, and her jaws, useless for 
sucking, are devoted altogether to the gathering of 
the pollen; she does not feed in the perfect state. 
Doubtless her ancestors did so, and were first attracted 
to the Yucca in search of honey, though the act of 
pollination is now performed only for the sake of the 
offspring.” 
Among certain lower animals and plants symbiotic 
connection is often most intimate. For instance, in 
the body-wall of certain Sea Anemones and Holo- 
thurians there are small green cells which were long 
* G. H. Carpenter: “Insects: Their Structure and Life,’’ 
Pp 300. 
