DISTRIBUTION 381 



are distinctly Central American and West Indian in their 

 affinities. Indeed Uhler is inclined to believe that the principal 

 portion of the Hemiptera of the United States has been derived 

 from the region of Central America and Mexico. 



Eastern. On the Atlantic coast are many European species 

 of insects which have arrived through the agency of man. 

 Most of them have not as yet passed the Appalachian moun- 

 tain system, but some have worked their way inland. Thus 

 the common cabbage butterfly (Pieris rapce) , first noticed in 

 Quebec about 1860, was found in the northern parts of Maine, 

 New Hampshire and Vermont five or six years later, was 

 established in those states by 1867, entered New York in 1868 

 and then Ohio. Aphodius fossor followed much the same 

 course from New York into northeastern Ohio, as did also the 

 asparagus beetle (Crioceris asparagi) , the clover leaf weevil 

 (Phytonomus punctatus) , the clover root borer (Hylastes 

 obscurus) and other species. In short, as Webster has pointed 

 out, New York offers a natural gateway through which species 

 introduced from Europe spread westward, passing either to the 

 north or to the south of Lake Erie. 



Inland Distribution. Pieris rapce, the spread of which in 

 North America has been thoroughly traced by Scudder, 

 reached northern New York in 1868 (as above), but appears 

 to have been independently introduced into New Jersey in 

 1868, whence it reached eastern New York again in 1870; it 

 was seen in northeastern Ohio in 1873, Chicago 1875, Iowa 

 1878, Minnesota 1880, Colorado 1886, and has extended as 

 far south as northern Florida, but is apparently unable to make 

 its way down into the peninsula. 



Crioceris asparagi, another native of Europe, became con- 

 spicuous in Long Island in 1856, spread southward to Virginia 

 and westward to Ohio, where it was taken in 1886; it occurs 

 now in Illinois. This insect, as Howard observes, flies read- 

 ily, and may be introduced commercially in the egg or larval 

 stage on bunches of asparagus. 



Cryptorhynchus lapathi, a beetle destructive to willows and 



