130 SCLATEK ON THE GENERAL DISTRIBUTION OF AVE3. 



Fig. 



20. Cerapachys oculatus. 21. Head of the same. 22. Wing of the same. 



23. Antennae of the same. 24. Abdomen of the same. 

 25. Echinopla melanarclos. 26. Section of the abdomen of the same, 



showing the styles, or blunt spines, with hairs on their summits, 



which cover the abdomen above. 2". Maxillary palpus of the same. 



28. Mandible of the same. 29. Labial palpus of the same. 



Tab. II. 



1 . Myrmosida paradoxa. 1 a, antennas ; 1 b, wing. 



2. Crematog aster inflata. 1 b, wing ; 1 e, manble. 



3. Cataulacus horridus. 



4. Cataulacus insularis. 4 a, anterior wing. 



5. Meranoplus cordatus. 6. Meranoplus mucronatus. 

 7 . Meranoplus castaneus. 8. Cataulacus reticulatus. 



9. Tongue of Gayella pulchella. 9 a, labial palpi ; 9 b, paraglossae. 10. 



Maxilla. 10 a, maxillary palpi, 

 i 1 . Anterior wing of Gayella pulchella. 



On the general Geographical Distribution of the Members of the 

 Class Aves. By Philip Lutlet Sclater, Esq., M.A., 

 F.L.S. 



[Read June 16th, 1857.] 



An important problem in Natural History, and one that has 

 hitherto been too little agitated, is that of ascertaining the most 

 natural primary divisions of the earth's surface, taking the amount 

 of similarity or dissimilarity of organized life solely as our guide. 

 It is a well-known and universally acknowledged fact that we can 

 choose two portions of the globe of which the respective Faunae 

 and Horse shall be so different, that we should not be far wrong 

 in supposing them to have been the result of distinct creations. 

 Assuming then that there are, or may be, more areas of creation 

 than one, the question naturally arises, how many of them are 

 there, and what are their respective extents and boundaries, or 

 in other words, what are the most natural primary ontological di- 

 visions of the earth's surface ? 



In the Physical Atlases lately published, which have deservedly 

 attracted no small share of attention on the part of the public, too 

 little regard appears to have been paid to the fact that the divi- 

 sions of the earth's surface usually employed are not always those 



