820 General Notes. [ October, 
treating of the apple tree plant louse,! has usually been attribued 
to natural enemies of the Aphids, but these play only a part in 
causing it. The fact of migration rests, moreover, on repeated di- 
rect observations, and all spring gall-inhabiting species have us- 
ually vacated their galls by mid-summer. The air has often been 
seen to swarm with Aphids, and Reaumur observes that in migra- 
ting they sometimes actually darken the air. In fact it is now 
coming to be well understood, that in this family the habit of the 
same species in spring is quite different to its habit in the fall, and 
that in the study of the insects of this family there is opened up 
to us a new and interesting field for observation comparable to 
that of late years developed by the discovery of dimorphism in the 
Cynipide. e have for some time since recognized this fact of 
migration, but have been led to believe from the known facts in 
the case that the migration was necessarily from one plant to 
another of the same gezus. M. Lichtenstein, on the contrary, be- 
lieves that the change is still more wonderful and that many tree- 
inhabiting and gall-making species actually have a mid-summer 
life on the roots of grasses and herbaceous plants. He has re- 
cently communicated to us some discoveries that certainly justify 
his views. In the genuine Ap/idini he has ascertained that ApMs 
(Phorodon) humuli migrates from Prunus to Humulus, and that 
Aphis (Myzus) asclepiadis Passerini (nerii Boyé) migrates from 
Asclepias to Nerium. ‘ 
Tue Cuinca Buc.—The connection of meteorological condi- 
tions, especially the amount of rain-fall, with the increase OF de- 
crease of this notorious pest has long been recognized by entomo 
ogical writers. From a résumé of the chronological history of 
bad chinch bug years and the effect which temperature may ave 
on the insect, Professor Cyrus Thomas showed a year ago ( Amer- 
ican Entomologist, Oct., 1880) that the insect would probably be 
bad in 1881. How disastrous it really has been in the Westem 
States, especially in Kansas, may be gathered from the fact that a 
chinch bug convention, the first ever held in the U. S., was held 
recently at Windsor, Kansas. A large number of farmers partic 
pated in the discussion, and a- resolution to exclude wheat ron 
the growing crops was unanimously adopted—the length of time 
not being mentioned. It is understood, however, that the plant- 
ing will be resumed at the earliest possible practicable pertoe 
Anticipating that this would be a bad chinch bug year, Pr —— 
omas recommended the sowing of a larger area of oats, a0 
had this advice been more generally adopted it would have been 
of great benefit to the farmers of that region. The insect has been 
quite common in all parts of the country the present year. It at 
tacked and injured, during the month of August, the rice fields eee 
_ the vicinity of Savannah, Ga., and was noticed in July in great 
' Treatise on Insects most prevalent on Fruit Trees and Garden Produce. Lon- 
don, England, 1829. . . 
