472 HUTCHINSON'S POPULAR BOTANY 



a mile square, in the neighbourhood of Alamos, Mexico. The fruit is of 

 triangular shape, divided into three equal portions by strongly defined 

 lines. Two of these parts contain a small spherical black seed: the 

 third, a "jumper" or small maggot. On falling to the ground the fruit 

 splits, and that portion which contains the maggot immediately starts off, 

 hopping in an extraordinary manner away from the tree on which it grew. 



The object of these movements has not yet been discovered, but the 

 theory is that the maggot instinctively knows that if it remains near 

 the parent tree it will be destroyed by an enemy. The insect lives upon 

 the contained seed, and has no desire to escape indeed, seems to be 

 extremely comfortable in its dark quarters. If a small hole is carefully 

 bored in the shell, the maggot instantly sets to work to repair the damage, 

 and in a very short time will have closed the hole with a fine silky web. 

 After this is done the insect resumes its tireless and saltatory travels. As 



FIG. 579. STRAWBERRY (Fragaria vesca). 



The first figure shows (a) ovary, (6) style, and (c) lobed stigma. The second figure is a section through the receptacle 

 (a) of an unripe " berry," with membranous pistils seated on the surface. The third figure shows the same in a ripe 

 condition with carpels on the exterior ; and the remaining figure is a section through one of the carpels, showing 



the contained seed. 



there is no hole or other indication of a way by which the shell could 

 be entered, it is supposed that the egg is laid in the flower before the 

 fruit is formed ; probably also, the moth which lays the egg cross-pollinates 

 the flower at the same time. The perfect insect is a grey-brown moth, 

 with speckled upper wings which measure three-quarters of an inch from 

 tip to tip. The moth releases itself from its prison by chiselling out a piece 

 of the hard shell, like a circular pavement-trap in miniature. The most 

 delicate fret-saw, even in skilled hands, could not do the work better. 

 It must be understood that these "jumping beans" never produce seedlings, 

 for the contained larva destroys the seed. 



Instances are even known of whole plants which migrate from place 

 to place when their fruits are ripe. Of this sort are the wonderful " wind- 

 witches " of the Russian steppes, which have so appealed to the imagination 

 of the peasants of those regions. At the fruiting stage the stiff erect 



