102 INTRODUCTION 
Hypochoeris, Taraxacum) belonging to the Cichoraceae, which they visit with special 
eagerness. Here they are protected by the marginal florets, which fold over them. 
Small beetles also, especially species of Meligethes, remain at night in the flowers 
or inflorescences they visit during the day, and in which, owing to the respiration of 
these floral parts, there is doubtless a higher temperature than in the surrounding air. 
Even in the daytime the small flower-beetles: just named often remain for 
many hours in one and the same flower, and may even stop there the whole day. 
Even larger beetles, such as the Cetoniae, linger a very long time in some flowers, 
especially in those of Magnolias, which Delpino for that reason has described as 
‘Kiaferblumen ’ (Beetle-flowers) (cf. p. 15). I have repeatedly observed the earwig 
(Forficula auricularia) staying for hours in flowers that are more or less closed, 
e.g. in those of Tropaeolum majus, Trollius europaeus, Arisarum vulgare, and others. 
Sometimes the stay of insects in flowers or inflorescences is against their will. 
This is the case in ‘ pitfall-flowers,’ such as Arum maculatum, italicum, and others. 
Arisarum vulgare, and Aristolochia Clematitis, in the flower-traps of which numerous 
small flies or moths are found; also Dracunculus vulgaris, in a single spathe of which 
Arcangeli found on one occasion 258 carrion-beetles. Insects enclosed in the flowers 
or inflorescences of pitfall-flowers are mostly compelled to stay in their recesses by 
hairs or bristles, which temporarily prevent egress until the anthers dehisce and the 
guests have covered themselves with pollen. Particulars with regard to these 
extremely remarkable flowers will be given in the sequel. . 
Flowers also now and then afford shelter to larval insects, which they allow 
to develop in their interior; as a return the adult insects effect pollination. In the 
flowers of Crambe maritima, for example, I observed numerous Meligethes larvae, 
which, like the beetles themselves, fed on the stamens and carpels. In spite of this 
they are not to be regarded as injurious to Crambe. For since the beetles are here 
the chief agents of pollination, if they and their larvae were present in smaller num- 
bers many flowers would remain unfertilized, though it is also true that some would 
escape injury. 
Still more interesting are the relations between Yucca and Ficus, and the moths 
or gall-wasps, respectively, which develop within their flowers. (See Fig. 17.) 
Through the investigations and observations of W. Trelease, we know that the 
capsule-bearing species of Yucca indigenous to North America are pollinated by 
a moth, Pronuba Yuccasella Z7e/., the females of which enter the flower that is open 
only at night, not in order to eat the pollen, but to carry it away, so as to provide 
their offspring with the necessary food. In order to render possible this transport 
of pollen, the first joint of the maxillary palp is very much elongated and can be 
rolled up, so that the Yucca moth can gather the pollen into a ball, which it holds 
under its head and carries away to another flower. Here the female clings to two 
filaments, introduces her ovipositor into the tissue of the pistil, and lays her eggs. 
She then pushes the pollen-ball that she has brought with her into the funnel-shaped 
stigma, so that pollination results. After a few days the larvae escape and are 
nourished by the young seeds, each of them consuming from eighteen to twenty before 
it is full grown. Pupation follows in the earth, after the larva has eaten through the 
wall of the ovary, and has let itself down by a thread which it spins. The seeds that 
are not consumed by the larvae then become ripe, and serve to propagate the species 
