HYMENOPTEEA. 397 



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 larvae on bees, 

 having first numbed them by its sting ; Pompilus and Sphex, 



Fig. 371. PliilanUiua triangulum. Fig. 72. MutfflaEuropaa. 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 Mutillce are 

 parasitical on solitary bees, their larvae devouring the larvae 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 num- 

 ber 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 

 Ichneumons introduce their eggs under the skin of caterpillars. 



