PROBABLE ORIGIN AND DIFFUSION. 77 
bugs mostly acquire fully developed wings. He had uever found the 
species in grain fields of any sort, but always in grass land-, generally 
in timothy or clover, but sometimes in wdd grasses. ( )f eleven speci- 
mens collected from under the bark of an old log by Mr. J. Pettit, of 
Grimsby, Ontario, in L866, and sent to Mr. B. I). \^ ;i 1 r- 1 » for determi 
nation, all were of the short-winged form. Ii was these specimens 
that doubtless led Doctor Riley 6 to call attention to the fact thai 
in Europe there are many genera <>f half-winged bugs which occur 
in two distinct or "dimorphous" forms with no intermediate grades 
between the two. viz, a short-winged or sometimes a completely 
wingless type and a long-winged type. Frequently the two occur 
together and copulate promiscuously, while sometimes the long- 
winged type occurs in particular seasons, especially in very hot sea- 
sons, while more rarely the 4 short-winged type occurs in a different lo- 
cality from the long-winged type, and usually in that case in a more 
northern locality. In northeastern Ohio the species occurs during 
some years in great abundance and wvy largely at least on timothy. 
]{(')■{' the short-winged form is very largely in the majority, and in 
the spring of ls ( .>7. of 1,900 specimens collected indiscriminately, 
only about loo were of the long-winged type. 
In northern Indiana, where the insect occurs but rarely, this short- 
winged type doe- not predominate; but aside from these two locali- 
ties, with an acquaintance with this species running over forty years, 
chiefly in Indiana and Illinois, the writer has never met with the 
short -winged type among millions of adults. If this short-winged 
type occurs elsewhere to the westward, except along the Pacific 
coast, where both forms have been collected by Koebele and others, 
it has not been found by entomologists, even to the northward as 
far a- Minnesota, Winnipeg, and Manitoba, while to the eastward 
of this Mr. Van Duzee collected the brachypterous form on Muskoka 
River, Ontario, near the lake of that name/ On comparing speci- 
men- from New York with a large series from Kansas, the former 
were found to be quite uniformly more robust, with longer hairs 
on the pronotuni.'' 
It would seem that here we have evidence of two distinct tides of 
migration, the one -weeping north and eastward, while the other has 
mainly been to the north and westward., meeting the former in north- 
eastern Ohio and northern Indiana, and possibly somewhere farther 
to the north in British America. The two. besides differing in the 
length of the wing-, are sufficiently unlike in appearance to attract 
the attention of students of Hemiptera. 
" Practical Entomologist, Vol. EI, p. 21. 
b Second Report on tin- Insc-is of Missouri, p. 22, 1870, 
'('.•in. Km.. Vol. XXI. p. ::. 1889. 
(i Lor. cit, Vol, XVII I. p. 209, 
