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That the ants value their useful cattle, and carefully watch 

 over them, there is abundant evidence ; they regularly visit them 

 for the purpose of milking them, and, according to Dr. Fitch, 

 " some of the ants remain constantly by them night and day to 

 protect t]ies.e small, weak creatures from being molested by their 

 insect or other enemies. Thus, before we are able to inspect a 

 colony of plant lice, we are first obliged to brush off or destroy 

 the ants which are guarding them,'' The late Dr. Walsh says, 

 "It is certainly true that the ants, if they can help it, will not 

 allow any winged fly to visit their milch kine, being probably 

 afraid that such flies come to rob them of the sugary fluid in 

 which they take sujh delight. Thus, unconscious of what they 

 are really doing, they often drive off Ichneumon flies, that would 

 otherwise deposit their eggs in the bodies of the plant lice, and 

 Fi.i;. .5. thereby cause their death, and S!/rj:ikM.s flies that would otherwise 



lay their eggs among the plant lice. But I have repeatedly seen them gathering in crowds 

 round one of the fiit fleshy aphis-devouring larvae of the Syrp/nis flies, pulling him about in 

 every direction, as if to ascertain whether he had got any honey in his body, like their friends 

 the ]ilant lice, and then, having apparently satisfied themselves that the fat gentleman was 

 not in the grocery business, and not knowing that he butchered daily hundreds of their 

 honey-producing friends, turn away in despair, and leave him, unharmed and unwounded, to 

 his own devices, as a hard case that nobody could make anything of. It is apparently for the 

 same reason, namely, to prevent sugar-loving flies from robbing tliem of their own private and 

 peculiar honey dew, that ants occasionally construct a kind of tent round a little flock of 

 their plant lice, but only where those plant lice are located on a twig, and never, so far as I 

 have observed, where they are located on a leaf" 



Notwithstanding all the care the ants may take to repel intruders, thousands of flies 

 share in the sweets produced by the plant lice, and often the location of a colony of these in- 

 sects, which would perhaps otherwise escape observation, may be detected by the loud buzz 

 occasioned by the disturbance of the attending flies. 



But there is .seldom a rule without its exception, and while the details given above ap- 

 ply correctly to hundred of different species of plant lice, yet in the case of the grain plant 

 louse, Ap/iis avenae, although the lioney tubes arc well developed, yet they emit no honey, and 

 in consequence of this, as has been remarked by Dr. Fitch, this species is not attended by 

 ants. To use the words of the late Dr. Walsh, " as this peculiar breed of cows gives no milk, 

 the milk maids do not think it worth while to visit them. 



Having now given our readers same idea of the general habits and immense fecundity 

 of these interesting insects, we shall refer in some detail to a few of the most troublesome 

 and destructive species reserving what we have to say in regard to the remedies which 

 nature has provided or man invented for their destruction until we have completed the 

 enumeration. 



The Apple-plant Louse {Aplm mali). * 



This insect which is represented in fig. 4 is the same as that which similarly infests 

 the orchards in Europe and has doubtless been introduced on the trees imported into this 

 country from across the Atlantic. The insects of this species of the previous year deposit 

 in the ftill in the cracks and crevices of the bark of the apple tree large numbers of their 

 small oval l)lack shining eggs. A large proportion of these are dislodged by the 

 cold, driving rains and snows of winter, and destroyed ; doubtless also, multitudes are de- 

 voured by the smaller insectiverous bird.s. The survivors hatch quite early in spring be- 

 fore the buds are fully expanded, when the young lice locate themselves on the small, 

 tender leaves displayed by the bursting bud, and there inserting their sharp leaks into the 

 tissues of the leaves, pump out their juices. The wingless specimens are of a pale, yellow- 

 ish, green colour with a yellow head and Idack eyes and are less than the tenth of an inch 

 in length. The winged specimens have the head antenna; and thorax black, and the body 

 green. 



3 



