2 80 ENTOMOLOGY 



products. The attendance of ants upon colonies of plant lice is a com- 

 mon occurrence and one that repays careful observation. With the 

 aid of a hand-lens, one may see the ants hastening about among the plant 

 lice and patting them nervously with the antennae until at length some 

 aphid responds by emitting from the end of the abdomen a glistening 

 drop of watery fluid, which the ant snatches. This fluid, contrary to 

 prevalent accounts, is not furnished by the so-called honey-tubes of the 

 aphid, but comes from the alimentary canal; the "honey-tubes'' are 

 glandular indeed, but are probably repellent in function. In some in- 

 stances ants give much care to their aphids, for example covering them 

 with sheds of mud, which are reached through covered passageways. 

 More than this, however, some ants actually collect aphid eggs and pre- 

 serve them over winter as carefully as they do their own eggs. In one 

 such instance Lubbock found that the aphids upon hatching, after six 

 months, were brought out by the ants and placed upon young shoots of 

 the English daisy, their proper food plant. In our own country, as 

 Forbes has discovered, the eggs of the corn root louse (Aphis maidira- 

 dicis] are collected in autumn by ants (especially of the genus Lasius) and 

 stored in the underground nests. In winter the eggs are taken to the 

 deepest parts of the nest, and on bright spring days they are brought up 

 and even scattered about temporarily in the sunshine; while if a nest is 

 opened, the ants carry off the aphid eggs as they would their own. In 

 spring the ants tunnel to the roots of pigeon grass and smartweed, seize 

 the aphids and carry them to these roots, and later to the roots of Indian 

 corn. Throughout the year the ants exercise supervision over these 

 aphids; occasionally, as Forbes says, an ant seizes a winged louse in the 

 field and carries it down out of sight, and in one such instance it appeared 

 that the wings had been gnawed away near the body, as if to prevent the 

 escape of the louse. Similar relations exist also between ants and some 

 species of scale insects. 



Guests. Though Aphididae and Coccidae are able almost always to 

 live without the help of ants, there are some insects which have never 

 been found outside the nests of ants. Most of these insect guests are 

 beetles, notably Staphylinidas and Pselaphidae. The rove-beetles make 

 themselves useful by devouring refuse organic matter, and these scav- 

 engers are unmolested by the ants with which they live. A few myrme- 

 cophilous beetles furnish their hosts with a much-coveted secretion and 

 receive every attention from the ants, which clean these valuable beetles 

 and even feed them mouth to mouth, as the ants feed one another. 

 Lomechusa (Fig. 290) is one of these favored guests, as it has abdominal 



