128 UTILITY AND DESTRUCTION OF REPTILES. 
But the action of the creeping and swarming things of the 
earth, though often passed unnoticed, is not without important 
effects in the general economy of nature. The geographical 
importance of insects proper, as well as of worms, depends 
principally on their connection with vegetable life as agents of 
its fecundation, and of its destruction. We learn from Darwin, 
“On Various Contrivances by which British and Foreign Or- 
chids are Fertilized by Insects,” that some six thousand species 
of orchids are absolutely dependent upon the agency of insects 
for their fertilization, and that consequently, were those plants 
unvisited by insects, they would all rapidly disappear. What 
is true of the orchids is more or less true of many other vegeta- 
ble families.* We do not know the limits of this agency, and 
mass, the decayed exuvie of even the smaller and humbler forms of life are 
sometimes abundant enough to exercise a perceptible influence on soil and 
atmosphere, ‘‘ The plain of Cumana,” says Humboldt, ‘‘ presents a remark- 
able phenomenon, after heavy rains. The moistened earth, when heated by the 
rays of the sun, diffuses the musky odor common in the torrid zone to animals 
of very different classes, to the jaguar, the small species of tiger-cat, the 
cabiai, the gallinazo vulture, the crocodile, the viper, and the rattlesnake. 
The gaseous emanations, the vehicles of this aroma, appear to be disengaged 
in proportion as the soil, which contains the remains of an innumerable mul- 
titude of reptiles, worms, and insects, begins to be impregnated with water. 
Wherever we stir the earth, we are struck with the mass of organic sub- 
stances which in turn are developed and become transformed or decomposed, 
Nature in these climes seems more active, more prolific, and, so to speak, more 
prodigal of life.” 
* Later observations of Darwin and other naturalists have greatly raised 
former estimates of the importance of insect life in the fecundation of plants, 
and among other remarkable discoveries it has been found that, in many 
cases at least, insects are necessary even to moncecious vegetables, because 
the male flower does not impregnate the female growing on the same stem, 
and the latter can be fecundated only by pollen supplied to it by insects from 
another plant of the same species. 
‘* Who would ever have thought,” says Preyer, “that the abundance and 
beauty of the pansy and of the clover were dependent upon the number of 
catsand owls? Butsoitis. The clover and the pansy cannot exist without 
the humble-bee, which, in search of his vegetable nectar, transports uncon- 
sciously the pollen from the masculine to the feminine flower, a service which 
other insects perform only partially for these plants. Their existence there- 
fore depends upon that of the humble-bee. The mice make war upon this 
