THE CANADIAN ENTOMOLOGIST 111 



So far as I know,. it is confined to the Atlantic States and Western 

 Europe. Aradus cinnamomeus is in the same case; and Aradiis 

 lugubris of Fallen was independently recognized by Say also in 

 1832, who called it rectus, and by Kirby in 1837. It appears to 

 extend throughout the northern part of this continent, from east 

 to west and through Siberia into Western Europe. Seemingly, 

 then, lugubris has come in by way of Bering Strait, and has 

 travelled eastward. As to the other two, their dispersal might 

 seem to indicate human agency. It is conceivable that they have 

 travelled east into Europe, or west out of Europe concealed in 

 crevices in logs and planks or under loose bark. The earlier dis- 

 covery of crenatus in this country might appear to indicate its 

 American origin, while the fact that cinnamomeus is first recog- 

 nized in Europe might perhaps lead to the inference that that 

 was its native soil, but possibly erroneously, since being a dweller 

 in pine trees it may conceivably have been exported in such 

 timber from this Continent. 



There is another small group with a most remarkable distri- 

 bution. The type of these may be considered to be Nezara 

 viridula, which occurs with us commonly in Florida, and thence 

 down into tropic America, across the ocean into Africa, throughout 

 Europe and thence into Asia. Its home is said to be in Africa, 

 whence it has spread so widely. How? No explanation seems to 

 have been offered of its wanderings, but certainly there is no ques- 

 tion of the identity of the species, even though the examples come 

 from many lands. In this class, also, belongs Corizus hyalinus, 

 which has spread even unto the distant isles of the Pacific Ocean. 



It has not been the intention in these remarks to go deeply 

 into the subject or to expound a theory, but simply to set forth a 

 peculiar biological phenomenon and one well worthy of serious con- 

 sideration and study. A few forms in a restricted group have been 

 referred to, but all orders of insects present the same problem. 

 Where the migration is over extensive land areas with a more or 

 less homogeneous character of vegetation, or when one certain food- 

 plant is widespread, the question presents no difficulties, but where 

 large bodies of water intervene, it becornes more complex, and is 

 a fit subject for scientific inquiry of a high order. 



