APHIDIANS. 



APHIDES. 



warm weather. From this tree is extracted 

 a white odoriferous resin. The wood also 

 makes excellent tiring in stoves, ovens, and 

 kilns. 



[APHIDIANS. A group of minute insects, 

 which includes those commonly called plant- 

 lice. Some of these insects have the power of 

 leaping, like the leaf-hoppers, from which, how- 

 ever, they differ. These hoppers are by no 

 means so prolific as other kinds of plant-lice, 

 since they produce only one brood during the 

 year. They live in groups, composed of about 

 a dozen individuals each, upon the stems and 

 leaves of plants, the juices of which they im- 

 bibe through their tubular beaks. The young 

 are often covered with a substance resembling 

 fine cotton arranged in flakes. This is the case 

 with some which are found on the alder and 

 birch in the spring of the year. 



Another tribe of aphidians called Thrips, 

 are very small and slender insects, exceed- 

 ingly active in their motions. They live on 

 leaves, flowers, buds, &c. Their punctures 

 appear to poison plants, and often occasion 

 deformities in the leaves and blossoms. The 

 peach tree sometimes suffers severely from 

 their attacks, as from those of the true plant- 

 lice ; and they are found beneath the leaves, in 

 little hollows caused by their irritating punc- 

 tures. The same applications that are em- 

 ployed for the destruction of plant-lice may be 

 used with advantage upon plants infested with 

 Thrift. {Dr. HarriSs Report on Destructive 

 Insect ft.}] 



[APHIDES, or plant-lice, as they are com- 

 monly called, are found upon almost all parts 

 of plants, and there is scarcely a plant which 

 does not harbour one or two kinds peculiar to 

 itself. They are exceedingly prolific, and 

 Reaumur has proved that one individual, in 

 five generations, may become the progenitor 

 of nearly six thousand millions of descendants. 

 It often happens that the succulent extremi- 

 ties and stems of plants will, in an incredibly 

 short space of time, become completely coated 

 with a living mass of little lice. These are 

 usual 1}' wingless, consisting of the young and 

 of the females only; for winged individuals 

 appear only at particular seasons, usually in 

 the autumn, but sometimes in the spring, and 

 there are small males and larger females. 

 After pairing, the latter lay their eggs upon or 

 near the leaf-buds of the plant upon which 

 they live, and, together with their males, soon 

 afterwards perish. The genus to which plant- 

 lice belong is called Aphis, from a Greek word 

 signifying to exhaust They hatch out in the 

 spring and immediately begin to pump up sap 

 from the tender buds, stems, and leaves, in- 

 crease rapidly in size and quickly come to ma- 

 turity. 



" Plant-lice seem to love society, and often 

 hsrd together in dense masses, each one re 

 maining fixed to the plant by means of its long 

 tubular beak ; and they rarely change their 

 places till they have exhausted the part first 

 attacked. The attitudes and manners of these 

 little creatures are exceedingly amusing. 

 When disturbed, like restive horses, they be- 

 gin to kick and sprawl in the most ludicrous 

 manner. They may be seen, at times, sus- 



)ended by tiieir beaks alone, an,{ throwing up 

 their legs as if in a high frolic, but too much 

 engaged in sucking to withdraw their beaks. 

 As they take in great quantities of sap, they 

 would soon become gorged if they did not gut 

 rid of the superabundant fluid through the two 

 ittle tubes or pores at the extremity of their 

 bodies. When one of them gets running-over 

 full, it seems to communicate its uneasy sen- 

 sations, by a kind of animal magnetism, to the 

 whole flock, upon which they all, with one ac- 

 cord, 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, becomes 

 dark coloured, and greatly disfigures the foliage, 

 This appearance 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 ap- 

 prized of the presence of plant-lice on plants 

 growing in the open air by the ants ascending 

 and descending the stems. By observing the 

 motions of the latter we soon ascertain that the 

 sweet fluid discharged by the lice is the occa- 

 sion of these visits. The stems swarm with 

 slim and hungry ants running upwards, and 

 others lazily descending with their bellies 

 swelled almost to bursting. When arrived in 

 the immediate vicinity of the plant-lice, they 

 greedily wipe up the sweet fluid which has dis- 

 tilled 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 themselves, 

 upon which they frequently prey, treat the 

 plant-lice with the utmost gentleness, caress- 

 ing them with their antennse, 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 actu- 

 ally yield the fluid when thus pressed. A sin- 

 gle 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 in- 

 stantly remove the latter, nor will they allow 

 any dirt or rubbish to remain upon or about 

 them. They even protect them from their 

 enemies, and run about them in the hot sun- 

 shine to drive away the little ichneumon flies 

 that are forever hovering near to deposit their 

 eggs in the bodies of the lice." 



Plant-lice differ much in form, colour, length 

 of tubes, &c. The Rose-louse (Aphis Rosas) 

 has a long tube. The cabbage-louse (Aphis 

 Brassicse) has also long honey-tubes, its body 

 being covered with a whitish mealy substance. 

 This species is very abundant on the lower 

 side of cabbage-leaves in the month of Au- 

 gust. The largest species of plant-lice ob- 

 served by Dr. Harris, he found in clusters 

 beneath the limbs of the pig-nut hickory. He 



