39 



out to ho tlio point of llio proboscis, rrojoctiug beyond the 

 insect's body this instrument is not usually inserted into the 

 plant, but serves as a sheath for those long hair-like organs 

 which can bo protruded from it. With these the insect pierces 

 the leaves or stems, using them with a saw-like motion ; these 

 organs, however, are neither toothed nor barbed, but a plenti- 

 ful supjily of sap flows from the incision which is sucked through 

 the proboscis with a pumping action. 



The Aphides have nearly all soft oval bodies composed of 

 several joints ; thej- are sometimes much wrinkled, when the 

 joints are verj^ distinct ; but in some species, when food is 

 abundant, they become so distended that the joints are scarcely 

 visible. Many species are furnished with two curious organs 

 near the end of their T)odies, called cernicles, which are longish 

 tubular appendages, from which there occasionally issues a 

 drop of sweet, sticky fluid. These drops falling on to the leaves 

 or anj'thing below the plants on which the insects are feeding, 

 form the stick}' substance commonly known as "honey-dew." 

 Ants are particularly fond of this fluid, and will watch an 

 Aphis, sometimes gently tapping its sides with its antenncc imtil 

 a drop apjiears, which is immediately swallowed. The stories 

 of ants carrying Aphides into their nests and using them as cows 

 is probably the result of careless observations, for the Aphis 

 would be unable to supply the honey-dew imless it could 

 obtain an abundant supply of sap. Ants sometimes build their 

 nests partly among the stems of i)lants, which stems may be 

 covered with Aphides, from which the ants can obtain'the sweet 

 fluid they are so fond of. Certain species live underground, 

 feeding on the roots of various plants. Some of these have, no 

 doubt, been found in ants' nests, unhai-med by the ants, who have 

 l)robabl3' made their nest at the root of some plant infested with 

 these Aphides, these, however, have no cernicles, but probably 

 something of a sweet nature may exude from them. 



The American Blight is one of the most mischievous species ; 

 when once it attacks an orchard it is a most difiicult pest to get 

 rid of, for it exudes from between the joints of the body a 

 white cottonj', sticky substance, which is very light and easily 

 blown about, and often carries with it eggs and young Aphides, 

 Avhich form new colonies on neighlxniring trees, so that it is a 

 serious matter when this insect makes its appearance in an 

 orchard. This cotton}' covering is, I imagine, a great protection 

 to the insects, for many of their enemies would not be able to 

 reach them on that account. I have been imablc to find one of 

 these Aphides in the winged state, but on the slides under the 

 microscope you Avill sec tliem in various stages. You may notice 

 that the proboscis in the young ones is much larger in proi^or- 

 tion than in those which are more matui'e, iu fact so long that 



