﻿OF THE STATE ENTOMOLOGIST. 43- 



Mr. Bates lays some stress on the fact that few American plants 

 and insects have been acclimated in Europe, citing only the Common 

 Water Weed, {Anacharis Canadensis), which has spread through 

 their ponds and canals, and the Grape Phylloxera, which has done so 

 much injury to French vineyards. He also says that no American 

 beetle has become acclimated. While it is true that we have received 

 many more species than we have given, enough more of our insects 

 and plants have established themselves there to weaken the force ot 

 the objection. The Horse Weed, {Erigeron Canadense), and the Grape 

 Mildew, {Oidium TucJceri), may be added to the plants ; our common 

 White Ant, {Termes Uaniyes)^ has done much damage in some parts 

 of Germany; the Woolly Aphis, or American Blight, {Eriosoma 

 pyri), is quite a pest in England and on the Continent ; a minute 

 yellow ant, {Myrmica molesta), which so annoys our housekeepers, 

 has, according to Fr. Smith, been naturalized, and is very troublesome 

 in England ; while at least two of our beetles, viz., the Fea Weevil, 

 {Bruchus pisi), and the American Meal Worm, {Tenehrio ohscurus)^ 

 have been naturalized in Europe — the former doing some damage in 

 S. France; the latter being quite widespread and now sent back in 

 about equal numbers with the European Meal Worm, {Tenehrio 

 molitor), by those who make a business of rearing the worms for bird 

 fanciers. 



There is some force in all of his arguments, but Mr. Bates does 

 not sufficiently appreciate the exceptional adaptive and migrating 

 powers which the species has exhibited. There are hundreds of North 

 American insects — and some of the most injurious too — which no one 

 fears will ever reach Europe or establish themselves there, because 

 they are restricted, and have for years been restricted to certain geo- 

 graphical areas. They have exhibited no especial powers of adapta- 

 tion to new conditions. But our Potato-beetle forms one of those 

 exceptional cases that occasionally confront us. We mark and note 

 the exceptional vitality though we cannot give a reason for it. Why 

 has Doryphora lO-lineata overrun the country and become such a 

 pest, while its scarcely distinguishable congener, Doryphora j imcta^ 

 feeding on the same genus of plants, has proved incapable of that 

 adaptation, and remained harmless? Whatever the reason, the fact 

 weakens the force of all generalizations based on geographical distri- 

 bution. The reasons why the species has not passed west of the Bocky 

 Mountains, find also their best explanation in the facts already men- 

 tioned in considering the causes which limit its spread. 



The possibility of its importation, in a living condition, on 

 vessels, is now assured by the experience of the year 1876, and I 



