STATE HORTICULTUEAL SOCIETY. 301 



time as a recapitulation of the life history of this family as just given. The spring 

 brood consists exclusively of wingless viviparous females that go on increasing the 

 number of the colony in the usual manner. The winged viviparous females of the 

 summer broad were observed during July and August when the dispersion of the 

 species was going on, after which they disappeared and only wingless individuals 

 could again be found. In the fall I expect-^d to find the winged males of the last 

 brood, but after a most diligent search for them during September, October and 

 partly also November, until the cold weather set in, I was unable to find a single 

 specimen. Wingless males were repeatedly observed during this time, though few 

 in number in comparison with the other form. These could easily be recognized 

 as they are somewhat smaller and differ also considerably in color. After a care- 

 ful study of this form I am convinced that they are normal males, and the only 

 form found in this species. The wingless females of this last brood, after pairing, 

 deposit the eggs on top of the branches ready for hatching as soon as spring again 

 comes around. 



HOW WINTEK 18 PASSED. 



How the plant-lice do pass the winter is a question on which there still are 

 different opinions. In regard to most of the species it is still a mystery, as it has 

 been made out in but a comparatively few cases. All those species that are known 

 to deposit their eggs on trees in the fall, there is no doubt of that they do pass 

 the winter in this state. And I do believe that this will be the case with all as 

 they become better known. 



Doctor Thomas suggests that some very probably do pass the winter as a demor- 

 phised form on the roots of certain plants— dimorphism being known to occur in 

 several species of plant-lice — and that consequently many of those species inhabiting 

 roots will be found to be but a dimorphised form for passing the winter of some 

 aerial species. As Doctor Thomas seems to be pretty well satisfied that this is the 

 case with a large proportion of the pale, cream-colored subterraneous species, it de- 

 serves our consideration, but more extensive and thorongh study of the subject 

 will be necessary before the question can be set at rest. 



The root-inhabiting species that have come under my observation in this locality 

 are yet but few — only three species were found last summer, all of which are with- 

 out any doubt distinct species as is also apparent from the fact that they are found 

 not only in the fall, but during the height of the summer ; and that they occur 

 in different stages of develpement, as larvae, pupae and even acquiring wings 

 while still under ground. The three species observed were: Aphis middletonii, 

 Thos., found on the roots of the flea-bane; Schizoneura panicola, Thos., found on 

 the roots of several species of grasses ; and TycTiea ra dicola, Oest. , found on the 

 roots of the great rag weed, (Ambrosia trifida, L.) 



When the full life-history shall have been made out of these subterraneous spe- 

 cies we can look for a most interesting and valuable page in regard to this family. 

 With the exception of the well known dimorphised form of the woolly aphis of 

 the apple tree (Schizoneura lanigera, Hansen,) the corn plant louse {Aphis maidis. 

 Fitch.,) and the grape phylloxera, very little is known at present about this subject. 



That inhabiting roots is not the original mode of life in this family, but has 

 been acquired in time I think will be apparent to any one at all familiar with this 



