Origin and Diffusion of Blissus leucopterus and Murgantia histrionica. 147 



tain at various times since without securing it at all, I infer that it 

 occurs there but rarely, and as Packard's date was August, in the 

 midst of mid-summer migrating season, we may, in North America, 

 safely look upon its occurrence at that time as due to its nomadic 

 habits. Prof. Gillette, as he writes me, has found but three or four 

 specimens, probably stray individuals. How abundant it was found 

 on the volcano in Panama, I have no means of learning, but I 

 believe we can safely say that its occurrence in high altitudes is due to 

 its somewhat roving habits, especially at the periods of migration, 

 which, while it strengthens the idea that the insect might have crossed 

 the Alleghany Mountains at an early day, to precisely the same or 

 even a greater extent does it strengthen the theory of an early 

 spread over a much more level country, from the south. Therefore, 

 we may safely say that its normal habits is at an altitude of from a few 

 to 1,000 or possibly 1,200 feet above sea level. It is a plain-loving 

 species and, according to my own experience, running over some 

 forty years, it prefers a clay to a sandy soil. I believe with Mr. 

 Schwarz that it is not a psammophilous but a maritime species (or semi- 

 maritime, as I would put it) not a sand-loving but a coast-loving insect. 

 It certainly does not especially favor the near vicinity of the shores of 

 the great lakes, and I have never found it in close proximity to any of 

 these except in limited numbers. The outbreak in New York, pre- 

 viously mentioned, is the only instance on record where it has occur- 

 red in abundance close to any of the Great Lakes, and this case 

 hardly constituted an exception as the outbreak was more especially 

 along the St. Lawrence River, and some thirty or forty miles from the 

 eastern shore of Lake Ontario. To offset this, over the lower penin- 

 sula of Michigan and Northern Indiana, both lying between Lake 

 Erie and Lake Huron on the east and Lake Michigan on the west, the 

 country is almost uninhabited by the species, it being impossible to 

 find after continued search in favorable localities, more than an occa- 

 sional specimen, and I believe this to be true also of Ontario, Canada, 

 north of Lake Erie, even at a time when from Western Indiana, 

 westward to beyond the Mississippi River, they were proving a verit- 

 able scourge. (See fig. 1, on next page.) Hence, while it is sea- 

 loving, it cannot be said to be lake-loving, clearly preferring the 

 proximity of salt to fresh water. I have stated that it is a plain 

 inhabiting insect, but it may inhabit very limited, flat areas, inter- 

 spersed among those more broken and elevated. 



