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INSHCIS IN RELATION TO PLANTS 
with special reference to their use by ants, though this is a 
gratuitous and improbable assumption. 
Belt found several species of Acacia in Nicaragua and the 
Amazon valley which have large hollow stipular thorns, in- 
habited by ants of the genus Pseudomyrma. The ants enter 
by boring a hole near the apex of a thorn (Fig. 264, 5). The 
plant affords the ants food as well as shelter, for glands (¢) 
Fic. 265. Fic. 266. 
Portion of young stem of Cecropia adenopus, Cecropia adenopus. Por- 
showing internodal pits, @ and b. Natural size. tion of a stem, split so as 
Figures 265-267 are from Schimper’s Pflanzen- to show internodal cham- 
geograpiue. bers and the intervening 
septa perforated by ants. 
at the bases of the petioles secrete a sugary fluid, while many 
of the leaflets are tipped with small egg-shaped or pear-shaped 
appendages (b) known as “ Belt’s bodies,” which are rich in 
albumin, fall off easily at a touch, and are eaten by the ants. 
These ants drive away the leaf-cutting species, incidentally 
protecting the tree in which they live. 
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