226 THE NATURALIST IN NICARAGUA. [Cli. XII. 



nislied with glands on the stipules, and in other species 

 they are more numerous, until in the wild Rosa vittosa of 

 the northern counties the leaves are thickly edged, and 

 the fruit and sepals covered with stalked glands. I have 

 only observed the wild roses in the north of England, 

 but there I have never seen insects attending the glands. 

 These glands, however, do not secrete honey ; but a dark, 

 resinous, sticky liquid, that probably is useful by being 

 distasteful to both insects and mammals. 



If the facts I have described are sufficient to show that 

 some plants are benefited by supplying ants with honey 

 from glands on their leaves and flower-buds, I shall not 

 have much difficulty in proving that many plant-lice, 

 scale-insects, and leaf-hoppers, that also attract ants by 

 furnishing them with honey-like food, are similarly bene- 

 fited. The aphides are the principal ant-cows of Europe. 

 In the tropics their place is taken in a great measure by 

 species of coccida3 and genera of Homoptera, such as 

 Membracis and its allies. My pine-apples were greatly 

 subject to the attacks of a small, soft-bodied, brown 

 coccus, that was always guarded by a little, black, 

 stinging ant (Solenopsis). This ant took great care of 

 the scale-insects, and attacked savagely anyone inter- 

 fering with them, as I often found to my cost, when 

 trying to clear my pines, by being stung severely by 

 them. Not content with watching over their cattle, 

 the ants brought up grains of damp earth, and built 

 domed galleries over them, in which, under the vigi- 

 lant guard of their savage little attendants, the scale- 

 insects must, I think, have been secure from the attacks 

 of all enemies. 



Many of the leaf-hoppers species, I think, of Mem- 



