498 STATE POMOLOGICAL SOCIETY. 



brood of those subject to the ont-door rigors of our climate, males and true 

 females are produced. These pair and deposit eggs, from which are hatched, 

 in <-he spring, only females. These do not produce true eggs, but there bud 

 out from their pseudovaries germs, which develop into aphides, just like the 

 parent. Thus, with no males all the long summer through, these agamic 

 females keep on reproducing their kind, for several broods, until the blasts of 

 autumn bring with the last brood of the season true males. Hence the increase 

 of these little creatures is so near infinity itself as to be almost incredible. 

 Reaumur proved that in five generations one aphis may be the progenitor of 

 about six billion descendants. And when I say that in a common season there 

 are twenty generations, you will no longer doubt that this remarkable fecun- 

 dity surpasses that of any other insect, or indeed that of any other known ani- 

 mal. Nor will you longer wonder that your roses and geraniums so rapidly 

 wither away when attacked by these prolific creatures. 



It is probable that nature has endued the aphis with such surpassing fecun- 

 dity in view of the fact of its many and rapacious enemies. Small birds, such 

 as the warblers, pewees, sparrows, and fly-catchers, devour hosts of them. The 

 larvse of some of the lace-wing, lady-bird beetle, and the ferocious larvfe of the 

 syphus flies, take them by myriads ; hence it is that a safeguard is needed 

 against their entire extermination. And what better could be provided than 

 their indefinite fecundity? When we consider, then, that in green-houses, and 

 on house plants these insects are exempt from their many foes, and more, that 

 the continuous warmth makes the production of males forever unnecessary, — 

 at least Kyber, by keeping a colony in a heated room, witnessed agamic repro- 

 duction for four years without exception, — we easily understand their alarm- 

 ing destructivenesp. 



The true female aphis is always apterous or wingless. The males always 

 possess wings, while the ovoviviparous agamic females may have wings, though 

 usually, she too is apterous. 



The most common color of those aphides which prey upon house plants is 

 green, though black aphides are by no means uncommon, and quite as destruc- 

 tive. These lice are known by green-house men as the green and black flies. 



The aphides are small insects frequently not more than an eighth of an inch 

 in length, with flask-shaped bodies, long, tapering autennre, a strong beak, and 

 frequently possess honey tubes extending from the posterior part of the abdo- 

 men, from which exudes a sweet secretion. Those plant lice which do not 

 possess the tubes, frequently secrete a similar fluid from the ground surface of 

 the body. 



Many of you have noticed with what assiduity the ants wait upon the aphides, 

 and have doubtless wondered at such warm demonstrations of attachment ; 

 for true it is, that hardly a plant is attacked with aphides without also harboring 

 a full colony of busy ants. These ants are there for the purpose of sipping up 

 the sweets which ooze from the nectaries of the plant lice. No wonder then 

 that the ants will forsake even their own young, in order to protect the plant 

 lice when danger threatens, for the aphides are both meat and drink to them, 

 and the same reason that insures to the short-horns the fostering care of the 

 breeder, secures to the plant lice the best attentions from the dependent ants. 



The method by which these liliputian destroyers impoverish the plants which 

 they assail, is by sucking out the juices which form the very life blood of the 

 plant. And when we consider that these sappers are frequently numbered by 

 the thousands, — aye millions, — we no longer wonder that even these tiniest of 

 creatures so soon sap the vitality of our vegetable treasures. 



