PROBABLE ORIGIN AND DIFFUSION. S7 
under one set of conditions, all traces of a short-winged form might 
entirely disappear, while with another set of conditions this tendency 
might not only be perpetuated, but greatly emphasized. The two 
species, B. Jeucopterus and B. doriw, are fully illustrated in all stages 
of development, as well as both macropterous and brachypterous 
forms. (See figs. on pp. 21, 22, 23, 83, 84.) For specimens of the 
latter species, B. doriw, we are indebted to Professor Sajé. 
PREVIOUS IDEAS ON THE DIFFUSION OF THE CHINCH BUG. 
Formerly it was supposed that the chinch bug was a native of the 
Atlantic coast States, and that it made its way westward with the 
advance of civilization and the consequent progress of wheat growing. 
This theory was based upon the fact that the original description was 
drawn up from a specimen from the eastern shore of Virginia, col- 
lected by Mr. Say himself,‘ and, as before stated, the earliest destruc- 
tion on record caused by this insect occurred in North Carolina, and 
it also committed great depredations in Virginia in 1839. Up to this 
time it had been Fans that it was a southern oes confined to 
the country south of latitude 40° north. But about this time chinch 
bugs appeared in I]linois, at Nauvoo, simultaneously with the settle- 
ment of the Mormons at that place, and as many supposed that this 
sect brought the bugs to the couhtry with them, they were toe 
termed * Mormon lice.” 
In his second report, page 284, Doctor Fitch states that Mr. Wil- 
liam Patten, of Sandwich, Dekalb County, I1., informed him that the 
chineh bug first appeared in that locality in 1850. Mr. Patten, the 
father of Prof. Simon Patten, of the University of Pennsylvania, 
and the writer’s father, settled in the immediate vicinity of Sandwich, 
TIL, in 1852. This was ten years after the Pottawattamie chief, Shab- 
bona, and his tribe had migrated to Kansas or Nebraska, the writer 
does not remember which, but he does recall that 1t was about this time 
that the prairie fires ceased to occur over any wide areas, as the prairies 
were no longer fired annually by the Indians. The whole country was 
fast being occupied, and he well remembers that the settlers would 
decide upon a certain date on which they would set fire to the wild 
grass—in late autumn—so that all could be prepared. It may also be 
stated that there were very few timothy meadows at that time, as the 
wild grass afforded an abundance of hay, and not until years after 
did cultivated grasses come into general use. The writer also knows 
from personal experience and observation that with the decrease in 
prairie fires there came an increasing abundance of chinch bugs, 
which attacked the wheat fields of the farmer. Up to about 1862 
these fields were largely of spring wheat, but about that time there 
@The complete writiugs of Thomas Say, edited by Le Conte, Vol. I, p. 
