OF NORTHUMBERLAND AND DURHAM, 141 



No doubt this may, in a great measure, be the result of our 

 northern latitude, variable climate, and strong clay subsoils, all 

 of which are most unfavourable to the development of this order 

 of insects, who are pre-eminently creatures of a southern clime, 

 a hot sun, and sandy soil. On the other hand, we are rich in the 

 more robust species ; we have all the Social or Common Wasps, 

 and nearly the whole of the Humble Bees. Many more species 

 will probably be added to our list when the southern part of the 

 County of Durham, and the northern part of Northumberland, 

 come to be examined, neither of which the business engagements 

 of the wiiter have allowed him to visit. The Cheviot range of 

 hills will be sure to produce boreal species, particularly Bombi, 

 some of which are peculiar to mountains. The fine turnip and 

 barley soils of the Wooler district are likely to suit the burrow- 

 ing habits of these creatui'es better, and to be richer in species 

 than the tenacious clays of the Coal-Measures. 



The principal books to which reference is made in the follow- 

 ing pages, are: — Linna3us, "Fauna Suecica, and Systema Na- 

 turae;" Fabricius, " Systema Piezatorum ;" Latreiile, "Histoire 

 Naturelle des Fourmis;" Kirby, "Monbgraphia Apium Angliae;" 

 Curtis, "British Entomology;" Shuckard, "Fossorial Hjonenop- 

 tera;" Stephens, "Illustrations of British Entomology, supp. ;" 

 Saint Fargeau, " Historie Naturelle des Insects;" Dahlbom, 

 "Hymenoptera Europffia;" Zetterstedt, "Insecta Lapponica;" 

 Wesmael, " Monographie des Odyneris de la Belgiq^ue;" Wes- 

 mael, " Eevue Critique Fouisseurs de la Belgique;" Smith," 

 "Monograph of the Bees of Great Britain;" Smith, "Mono- 

 graph of the British Fossorial Hymenoptera, Formicidaa and 

 Yespidfe." 



♦Although issued under the humble name of "Catalogues of the British Museum," these 

 two volumes are in reality most valuable and carefully executed Monographs, which are 

 quite iudispensible to the British student. The plates, engraved by Mr. Smith himself, are 

 perfect models of entomological delineation. 



