REASONS FOR PRESENT THEORY OF DIFFUSION. *1 
Fab., Hylastinus trifolii Mul.,and Grioceris asparagi Linn., all of which 
have first become destructively abundant west of the Allegheny Moun- 
tains in extreme northeastern Ohio. The last four species having been 
introduced from Europe, there is no doubt as to their migrating west- 
ward. 
An almost total lack of natural enemies in the United States, and 
with nearly all of its closest allies belonging in Mexico and the West 
Indies, it would seem as though we were in possession of additional 
evidence of its tropical origin. Besides this the name u chinch bug" is 
of Spanish origin, and this language has never been in common use in 
North America except in Florida and the country along the Mexican 
border. 
The species certainly prefers the low country to the higher, and is 
seldom found in any numbers at an altitude of over 2,000 feet. Gener- 
ally its habitat is 1,000 or lower. The altitude where it was found 
breeding on Volcan de Chiriqui, in Panama, is 6,000 feet; and of its habi- 
tations in Guatemala, San Geronimo, is 3,000 feet; Panzos, 2,000 feet; 
Ohamperico, sea level, and Rio Naranjo, about 2,000 feet, while in Colo- 
rado it occurs sparingly near Fort Collins at an elevation of 5,500 to 
6,000 feet, while Professor Cockerell did not find it at all in the same 
State at elevations of 7,000 to 8,000 feet. On Mount Washington, in 
New Hampshire, it has been found only once, and this time by Dr. 
Packard, on the summit, which has an elevation of 6,500 feet.* 
In my own experience, running over something like forty years, I 
have never witnessed serious injury to crops on hilly laud by chinch 
bugs. It may be stated, however, that all of my studies of the insect 
have been carried on in a level country, Ohio being the most uneven 
and hilly, but even here all of the outbreaks that I have observed were 
on level areas. In Minnesota, however, Dr. Lugger has found that 
those grain fields which are most seriously injured are located near the 
edges of woods or on slopes. In some published observations of Pro 
lessor Osborn, in Iowa, kindly placed at my disposal by Dr. Howard, 
I find that in 1894, about 90 per cent of the infested fields examined by 
Professor Osborn were on high ground and about 80 per cent of the 
fields were hilly and ridges, in most cases the damage being first appar- 
ent upon the higher portions of the fields. The exceptions were where 
the chinch bug had evidently hibernated in wild grass and weeds occur- 
ring in the lower places, and these had been very dry for the twelve 
months preceding the damage of that year. Besides, both the Iowa 
and Minnesota areas are below 1,000 feet elevation. 
The area over which the chinch bug is more especially abundant and 
destructive comprises such a variety of soils and geological formations 
that a study of these factors at once shows that neither has any mate 
rial intluence in the distribution of the species, at least in the United 
See my paper on Origin ami Diffusion of Blissua leucopterna and Murgantia histri- 
otiica, in Journal of Cincinnati Society of Natural History, Vol, Will. February . 1896, 
5968— No. 15 
