252 NEW YORK STATE MUSEUM 



leaving a transverse^ scar and a small opening-. The gall is at first rosy, 

 then green and is adorned with large curved spines. The second genera- 

 tion develops within the gall and early in July, about six weeks from the 

 birth of the stem mother, the winged adults migrate to the birch and 

 continue there till late in the fall. The third generation is developed on 

 the leaves and later wanders to the twigs and branches. The young are 

 Coccidiform and resemble a young Lecanium and in the early stages are 

 fringed with short waxy rods. They hibernate on the twigs and on the 

 stems, where they attain full maturity. The fourth generation returns to 

 the leaves, forms pseudo-galls by sucking the fluids from the under portion 

 and causing an arching up of the areas between the lateral ribs. The 

 young in the second stage bear conspicuous tufts of a white waxy secretion 

 on the sides of the posterior segments of the abdomen. The adults of 

 these produce the fifth or migratory generation which returns to the witch 

 hazel from early in July till about the middle of the month. It is much 

 like the preceding in character and is remarkable in the production of 

 accessory wingless females, parents of a secondary migratory generation, 

 which in turn flies to the witch hazel. The young of these migratory 

 generations, w^ingless males and females, pair and produce the winter eggs 

 which, as previously stated, are deposited between the middle of June and 

 early July. This latter life history is fully as remarkable as that of the 

 precetiing and, as noted above, it will be seen that not only is there an 

 alternation of food plants and alternation of generations but there is also a 

 prolonged life cycle and an extended period of nearly i i months passed in 

 the winter egg. 



These two species illustrate some of the remarkable features about 

 aphids or plant lice and it is very probable that further investigations would 

 reveal other hitherto unsuspected relationships. It is not at all impossible 

 that some of the 325 species supposed to be distinct, may in reality be only 

 different forms. Our knowledge of the Aphididae is altogether too limited 

 to permit the drawing of many general conclusions and the study of this 

 family both from the systematic and the biologic aspect affords a very 

 enticing held for the earnest conscientious worker. 



