Larval Dimorphism 



spot Is deemed favourable, she hovers round 

 inspecting it, then comes up suddenly and 

 strikes it with the tip of her abdomen. The 

 thing is done, the egg is laid. So I picture it, 

 at least. Within a radius of a few yards and 

 in a flight broken by short intervals of rest 

 in the sun, she carries on her search of likely 

 places for the laying and dissemination of her 

 eggs. The insect's assiduous attendance upon 

 the same slope is caused by the inexhaustible 

 wealth of the locality exploited. 



The Anthrax of the Chalicodoma labours 

 under very different conditions. Stay-at-home 

 habits would be detrimental to her. With 

 her rushing flight, made easy by the long and 

 powerful spread of her wings, she must travel 

 far and wide if she would found a colony. 

 The Bee's nests are not discovered in groups, 

 but occur singly on their pebbles, scattered 

 more or less everywhere over acres of ground. 

 To find a single one is not enough for the 

 Fly : on account of the many parasites, not all 

 the cells, by a long way, contain the desired 

 larva; others, too well protected, would not 

 allow of access to the provisions. Very many 

 nests are necessary, perhaps, for the eggs of 

 one alone; and the finding of them calls for 

 long journeys. 



97 



