STATE HORTICULTURAL SOCIETY. 299 



change, for it usually consists almost entirely of males and females ■which acquire 

 wings. These winged females, as previously stated, after pairing, deposit eggs 

 which remain over winter." 



In justice to this writer, it is proper here to remark that he gives us this history 

 as generally given and understood, wherefore he also calls our attention to the fact 

 that more careful and recent observations have shown, is in several respects to be 

 incorrect. 



One of the greatest objections to this life-history is that the winged females were 

 supposed always to be oviparious. It is now known that they, as a rule, are vivi- 

 parous, just as the wingless form that first comes in the spring ; and that they are 

 not only found in the fall, but more particularly during the summer. The ovipa- 

 rous females of the fall, on the other hand, are now known to be wingless. In 

 pursuance of these and some other facts the life-history will read somewhat dif- 

 ferent. 



SPRING BROOD. 



As soon as the leaves begin to make their appearance in spring, the eggs hatch, 

 and the young larvae are soon ready to insert their beak and begin to pump the 

 sap. This first brood can well be called the spring brood, though the word brood is 

 here used in a more special sense than usual, as strictly the plant lice cannot be 

 considered but one-brooded, and what we here call brood being simply a form; but 

 as the expression is very often used in treating of the plant-lice I find no objection 

 to it, and moreover, as it can not be well misunderstood when used in this connec- 

 tion. All the individuals of this brood are wingless females, which in a few days, 

 being full grown, begin to reproduce their own kind by giving birth to living lice , 

 similar t© themselves, and these, in turn, are soon ready to add to the number of 

 the colony. The number produced by each individual for the day varies, but under 

 favorable circumstances there are several, hence the very sudden and great increase 

 that we sometimes observe. 



These wingless females show very little desire to wander about, and usually pass 

 their whole life on .the same plant. The dispersion of the species is therefore not 

 the object of this brood ; their whole life being devoted to the increase of the colony^ 



SUMMER BROOD 



As soon as the warm days of summer have come we find that some of the young 

 lice differ considerable from the parents, especially in the presence of wing-pads 

 and in being more active. These young lice with wing-pads are called pup*, 

 which, after the last casting of the skin, come forth with full developed wings. In 

 descriptive entomology they are designated as the winged viviparous females, and 

 can also be considered as the second or summer brood. Boon after having ac- 

 quired wings, these also begin to bring forth living lice in the same manner as the 

 wingless or spring brood, and in this respect do not at all differ from the first brood. 

 But as the colony has by this time so increased in numbers as to make it uncomforta- 

 bly crowded for these individuals. These winged females soon begin to take to their 

 wings in search for new plants where to establish new colonies. The office of these 

 winged females, therefore, is not only to increase the colony in the same manner 

 as the wingless form, but in addition hereto they have as there duty the dispersion, 

 of the species. 



