HEMIPTERA. 



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withdraw their beaks. As tliey take in great quantities of sap, 

 they would soon become gorged if they did not get rid of tlie 

 superabundant fluid through the two little tubes or pores at 

 the extremity of their bodies. When one of them gets running- 

 over full, it seems to communicate its uneasy sensations, by a 

 kind of animal magnetism, to the whole flock, upon which 

 they all, with one accord, jerk upwards their bodies, and eject 

 a shower of the honeyed fluid. The leaves and bark of plants 

 much infested by these insects are often completely sprinkled 

 over with drops of this sticky fluid, which, on drying, become 

 dark colored, and greatly disfigure the foliage. This appear- 

 ance has been denominated honey-dew; but there is another 

 somewhat similar production observable on plants, after very 

 dry weather, which has received the same name, and consists 

 of an extravasation or oozing of the sap from the leaves. We 

 are often apprised of the presence of plant-lice on plants grow- 

 ing in the open air by the ants ascending and descending the 

 stems. By observing the motions of the latter we soon ascer- 

 tain that the sweet fluid discharged by the lice is the occasion 

 of these visits. The stems swarm with slim and hungry ants 

 running upwards, and others lazily descending with their bel- 

 lies swelled almost to bursting. When arrived in the immediate 

 vicinity of the plant-lice, they greedily wipe up the sweet fluid 

 which has distilled from them, and, when this fails, they station 

 themselves among the lice, and catch the drops as they fall. 

 The lice do not seem in the least annoyed by the ants, but live 

 on the best possible terms with them; and, on the other hand, 

 the ants, though unsparing of other insects weaker than them- 

 selves, upon which they frequently prey, treat the plant-lice 

 with the utmost gentleness, caressing them with their antennae, 

 and apparently inviting them to give out the fluid by patting 

 their sides. Nor are the lice inattentive to these solicitations, 

 when in a state to gratify the ants, for whose sake they not 

 only seem to shorten the periods of the discharge, but actually 

 yield the fluid when thus pressed. A single louse has been 

 known to give it drop by drop successively to a number of 

 ants, that were waiting anxiously to receive it. When the 

 plant-lice cast their skins, the ants instantly remove the latter, 



