396 THE INSECT WORLD. 
ants instal themselves in the nest whose inhabitants they have 
ejected, and transfer their own population to it. The motive for 
this emigration is that the old nest has become useless, or that 
it is exposed to some danger. The red ants are not the only 
ants which thus desert their birthplace. Many species abandon 
it likewise for analogous motives, and construct elsewhere another 
dwelling, to which they transport all the population of the first 
nest. : 
When one reflects on the habits of ants, one is forced to admit 
that intelligence and reason appear still more in their acts than 
in those of bees. The life of ants, as well as that of bees, as far 
as we are concerned, is an unintelligible enigma. The acts of 
animals, in general, are sometimes an abyss unfathomable to our 
reason. The Orientals say, “‘ The last word may be written on 
man: on the elephant, never!” Let us add that they should no 
more say that the elephant will be an inexhaustible theme, but 
that the history of the ant will continue so always. 
The best-known genus of the Fossores, or Fossorial Hymenop- 
tera, is Philanthus (Fig. 371), which feeds its larvee on bees, 
having first numbed them by its sting; Pompilus and Sphex 



Fig. 371.—Philanthus triangulum. Fig. 372.—Mutilla Europea. Male and female. 
which attack spiders; Mutilla (Fig. 372), whose females resemble 
ants, agreeably variegated with red and yellow; the males, pro- 
vided with wings and smaller in size, being black. The Mutille 
are parasitical on solitary bees, their larvee devouring the larve 
of these. 
Other Hymenoptera lay their eggs under the skin of certain 
insects, especially when these are in the larva or caterpillar: state, 
thus rendering service to agriculture by destroying a great 
number of noxious insects. In lieu of a sting they have an 
auger, intended to pierce the skin of their victims. It is thus that 
the Jchneumons introduce their eggs under the skin of caterpillars. 
