Origin and Diffusion of Blissus leucopterus and Murgantia histrionica. 153 



Anyone who is familiar with the nature of the country in eastern 

 Texas and Louisiana and understands this plain-loving character of the 

 chinch bug, will appreciate the temptation that would here present 

 itself for the insect to follow the level country inland, as well as along 

 the coast. We have observed how the southern extremity of the 

 Rocky Mountain system divided the current of the northward streams 

 of this insect, owing to its dislike for high elevations, and we now have 

 a second division, not influenced by mountain ranges, but by a fond- 

 ness for comparatively low and flat areas, not necessarily devoid of 

 trees but furnishing a supply of grass plants sufficient to afford food, 

 which, though not of the exact species found along the coast, yet 

 more abundant and equally suitable for the purposes required by the 

 insects. Thus, I would account for the spread of this species over 

 the country from the south instead of the east, as we have long held 

 to be the case and it seems to me that all its characteristics point to 

 Central America or the extreme northern portion of South America as 

 its original home. It may not be out of place to here call attention to 

 the possibility of some individuals being carried into the Caribbean 

 Sea or the Gulf of Mexico, and through the influence of the Gulf 

 Stream being transported to either Cuba or Forida — a possibility, but 

 not a probability, especially as regarding Florida. 



As showing that the route laid down in the foregoing for the 

 chinch bug is not a unique one, but has probably been followed by 

 other species, both before and since, I have chosen as an illustration 

 the Harlequin Cabbage bug, Murgantia histrionica, an insect belong- 

 ing to the same order as Blissus leucopterus, but to a different family. 

 With the barely possible exception of its closest ally, M. munda, with 

 whose southern distribution I am not familliar, all of the species at all 

 near related to this one are found in Mexico, Central America and 

 the West Indes. Like the chinch bug it is found in Costa Rica, Guat- 

 emala and Mexico, extending north on the Pacific coast into Califor- 

 nia and Nevada. In the east it occurs from Colorado to extreme 

 Southern Illinois and Indiana, and has appeared in Southern Ohio, 

 along the river within the last few years; in fact has only been 

 observed in the locality two or three years. Along the Atlantic, it is 

 found in the latitude of Philadelphia, Pennsylvania. Now, we are 

 able to trace the march of this species from Southeastern Texas, 

 about 300 miles from the mouth of the Rio Grande, where it was 

 first observed in 1864, though it was even then known in Louisiana, 



