PROBABLE ORIGIN AND DIFFUSION, S, 
under one set of conditions, all traces of a short-winged form might 
entirely disappear, while with another se< of conditions this tendency 
might not only be perpetuated, but greatly emphasized. The two 
species, B. leucopterus and />. dorice, are fully illustrated in all stages 
of development, as well as U>th macropterous and brachypterous 
Forms. (See figs, on pp. 21, 22, 23, s -"». 84.) For specimens of the 
latter species, />'. dorice, we arc indebted to Professor Sajo. 
PREVIOI 8 IDEAS <»N THE DIFFUSION OF THE CHINCH BUG. 
Formerly it was supposed that the chinch bug was a Dative of the 
Atlantic coast State.-, and that it made its way westward with the 
advance of civilization and the consequent progress of wheat gro^ ing. 
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 L839. Up to this 
time it had been supposed that it was a southern specie-, confined to 
the country south of latitude 40° north. But about this time chinch 
bugs appeared in Illinois, 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 country with them, they were locally 
termed " Mormon lice.*' 
In his second report, page 284, Doctor Fitch states that Mr. Wil- 
liam Patten, of Sandwich. Dekalb County, 111., informed him that the 
chinch 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. 
111., in 1852. This was ten year- 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 it 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 w r hole 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 
gra in late autumn — SO that all could he prepared. It may also he 
stated that there were very few timothy meadow- at that time. a- 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 persona] experience and observation that with the decrease in 
prairie fire- there came an increasing abundance of chinch bugs, 
which attacked the wheat fields of the farmer. Up to about L862 
these field- were largely of spring wheat, hut about that time there 
»The complete writings of Thomas Say, edited by Le Conte, Vol. I. p. 
