ON NORTH AMERICAN ZOOLOGY. 1/3 



and as temperature, moisture, and richness of vegetation have a 

 manifest connection with the abundance and variety of insects, 

 we look to find the insectivorous birds of the several continents 

 nearly as different as their floras. Mr. Swainson has indeed 

 already remarked that " it is among the insectivorous or soft- 

 billed birds that the principal ornithological features of any ex- 

 tensive region will be traced." These observations receive a 

 general support by a review of the extensive and varied order of 

 insesso7-es which in North America form three fifths of the 

 birds ; and though the hirimdinidce, which are purely insectivo- 

 rous, exhibit in the table a large proportion of species common 

 to the two continents, there is, as we shall mention again, reason 

 to doubt the identity of the species in the two faunae. Two or 

 three species of c&rmw ovoms, corvidce are with more certainty the 

 same on both sides of the Atlantic, and also several hard-billed 

 granivorous birds {fringiUidcB) that breed in the arctic re- 

 gions, the physical conditions of which are almost the same in 

 all longitudes, though below 65° N. latitude the aspect of the 

 tAVO continents differs greatly. 



Dentirostres. — In the quinarian arrangement of Mr. Vigors, 

 this is one of the five tribes into which the insessores, or perchers, 

 are divided, each tribe containing five families. Of tlje laniadcc, 

 a normal family of the tribe, only one species stands in our list 

 as common to the new and old continents, and it is so marked in 

 accordance with the opinions of Wilson and Audubon, but con- 

 trary to those of Vieillot, Bonaparte, and Swainson. This and 

 the other North American lanii are certainly very similar in 

 form to their Eui'opean congeners, which may be accounted for 

 by their approaching the rapaces in their mode of feeding, and 

 being less exclusively insectivorous than the tyraninae, associ- 

 ated with them by Mr. Swainson, which are proper to America. 

 The merulidcB, the other normal family of the tribe, contains 

 three American species which have been enumerated in the 

 European fauna, one {mericla migraturia) because of its occa- 

 sional appearance in Germany, and the other two, m. aurorea 

 and minor, on account of the capture of one or two individuals 

 in Saxony and Silesia. Of the numerous family of sylviadce we 

 scarcely know more than one species which has an undisputed 

 right to be marked as common to both sides of the Atlantic. 

 Saxicola oenanthe, hitherto detected only in the higher arctic 

 latitudes of America, may prove on further acquaintance to be 

 distinct from the more southern European bird bearing the same 

 name. Indeed Mr. Vigors has named it oeuanthoides, being 

 led to consider it to be a proper species, more from its distant 

 habitat than from any peculiar character detected in the speci- 



