2^0 



Marvels of Insect Life. 



Photo 6.v] 



Apple-tree Aphis. 



lL. i,Up, 1 L 



A batch of wingless green-fly on the leaves of apple. 

 These were not hatched from eggs, but boni in their 

 present form. They are all imperfect females, 

 and have the power to produce others like them- 

 selves and in the same manner. They are shown 

 about one-half larger than life-size. 



fluid wax, and is ejected at their enemies. This 

 w as for long confused with the sugary fluid known 

 ;is honey-dew, and ants have been figured receiving 

 It from these siphons after stroking the green-fly 

 with their antennae. The honey-dew is received 

 liom the extremitv of the hind-bodv, being in fact 

 the excreta from the Insect's intestine. The green- 

 t]\- would not discharge the product of its siphons 

 ;it its friend and protector, the ant. 



It may be presumed that the species that do 

 not possess these wax-secreting siphons are not so 

 subject to annoyance. This is certainly the case 

 with an underground species of grey colour, that 

 lives on roots, and is known as the ant-aphis, ^ 

 liecause of the fact that it is found on the roots of 

 grasses, etc., in, or in the immediate neighbourhood 

 of, ants' nests. It is so carefully watched over by 

 the ants that it is quite protected from any enemies 

 it might have otherwise. The ants even collect 

 and take care of its eggs during winter, and in 

 spring plant out the newly hatched green-fly in 

 places convenient for their own control. This 



habit has become 

 a serious pest to the growers of Indian corn in the 

 United States, for the ants at first plant their 

 " cows " out on the roots of cornfield weeds that 

 are ready for their reception before the maize is 

 sown, and later transfer them to the roots of the 

 latter plant. The amount of fluid produced by such 

 minute Insects may not strike one as being sufficient 

 to make it worth while for the ant to trouble itself 

 in the matter ; but careful observation has shown 

 that different species emit from nineteen to forty- 

 eight drops during twenty-four hours, and when one 

 considers the large number of green-fly comprised 

 in an ordinary colony of them it will be seen that 

 the aggregate output must be considerable. 



To found a big colony of green-fly it is only 

 necessary to establish a single individual of these 

 prolific, but sexually imperfect, females on a plant 

 in spring. In a few weeks after she has begun to 

 produce living young, the rate of increase is so 

 enormous that, but for the attacks of other Insects 

 and birds, all vegetation would soon be sucked dry. 

 Huxley made a calculation — since declared to be far 



^ Forda formicaria. 



I'twto by} 



Eggs of c.rf.en-Fly. 



.\ batcli of eggs of the apple-tree aphis laid in 

 autumn on a shoot of apple-tree. The eggs are 

 shining black, and hatch in spring. They give 

 rise to imperfect and wingless females, which 

 are able soon to i^roduci' living young with 

 similar powers of reproduction. 



