350 



PLANT LIFE. 



growing from special parts of the surface, which are regularly 

 eaten by the ants and grow again, so that a constant supply is 

 at hand ; (c] divellings of various sorts. Certain plants have 

 the stems hollow throughout, with special modification of the 

 structure at certain spots, so that an entrance to these hollows 

 may be readily made (fig. 393). In others, portions of the 

 internodes are much enlarged and hollow ; sometimes only 

 the internodes in the region of the flower clusters are thus 

 transformed. In other plants chambers are produced by the 

 bladdery enlargement of the under part of the leaf near the 

 midrib (fig. 394). In some acacias the stipules are developed 

 as massive thorns, which the ants inhabit. 



475. Domatia. Somewhat sim- 

 ilar dwelling places, though less 

 perfect, are provided by many 

 plants for the mites. These d \vell- 



FIG. 394. 



FIG. 395. 



B 



FIG. 394. Under side of the base of the leaf blade of Tococa land folia, showing 

 bladder on each side of midrib, each with entrance at a, a. Natural size. (?) After 

 Schumann. 



FIG. 395. Domatia on under side of leaves. A, between midrib and laterals of 

 Psychotria. B, between midrib and lateral of the linden (Tilia Europeea). Magni- 

 fied about 5 diam. After Lundstrom. 



ing places are in the form of minute shelters usually upon the 

 under side of the leaves. They are generally formed by hairs 

 roofing over an angle of the veins, or by various outgrowths, 

 folds and pits (fig. 395). Their significance is not at all 

 clear. 



