S6 Plant-Lice and Scale-Insects. 



thinner and flexible. Under the former division are grouped many species 

 of singular diversity of form, but all agreeing in their mode of obtaining 

 liquid nourishment by means of a jointed tube, or sucker, called haustcUurn. 

 So far as is known, all, without exception, are exhausters of the sap of plants: 

 many of the Heteroptera^ on the other hand, live exclusively on the blood 

 or juices of other animals. 



The Aphides, or plant-lice, of which several hundred species are described 

 (Walsh enumerates seventy from the U. S. Proc. Ent. See. Philad. i, 31), 

 are usually furnished with two honey-tubes projecting from the upper sur- 

 face of the abdomen. Through these tubes issue the elaborated juices of 

 the plants on which they feed, in the form of a sweet sirup called honey-dew. 

 Where the lice are numerous, this falls in great quantity, spotting the leaves, 

 and attracting various insects of other orders, as wasps, flies, and moths, to 

 partake of it. 



The almost romantic attachment shown by certain species of ants for 

 these little honey-makers, and the care and attention extended to them, arc 

 known to most readers. I have watched for a long time with great inter- 

 est the manoeuvres of the ants on the hickory or cherry, which are frequently 

 infested, the former with Lachnus caryee. (Harris), the latter with Aphis cerasi 

 (Fabricius). These are crowded upon the leaves, some with their beaks 

 buried so deeply as to appear as if standing upon their heads, pumping up 

 the sap, and swelling out their delicate bodies till they seem fit to burst ; 

 globules of the sweet secretion continually forming at the extremity of 

 each honey-tube, steadily increasing and dropping ; the busy ants running 

 hither and thither, now approaching, and lapping the drops, now rushing 

 with menacing air and open jaws at some eager wasp or fly, who, just arrived, 

 desires to share the repast, and whose conscience would not upbraid him 

 should he devour a few of the confectioners with their own sirup. Should 

 a thirsty ant not find a drop of honey exuding ready for his use, his elbowed 

 antennae gently stroke the body of the Aphis ; and, responsive to the touch, 

 the little animal jets out a drop for his friend and guardian. The Aphides, 

 which Hartig has separated under the name Pemphigus, live upon various 

 roots beneath the soil, and are still more carefully tended by the ants than 

 their brethren of the outer air ; for these carry them in their mandibles 

 from place to place, bringing them to the surface to receive the warm rays 



