278 OBSKRVATIONB INTRODUCTORY TO TIIR CATALOQUE OF 



111 tlic record of Hpocies, we have been under obligations to 

 several local collectors. The collections of Messrs. Albany and 

 John Hancock have furnished many rarities; and the Catalogue 

 will testify how much the Entomology of the district owes to the 

 researches of Mr. Wailes. 



The system genf^rally followed in the Catalogue, is that of Mr. 

 Westwood, given in the ")S//nopsis of the Oenera of Jiritisk Insects,'^ 

 appended to the 2nd volume of the '' Intro(hictlon to Entomology^'' 

 His list of genera, however, has undergone various modifications, 

 derived from more recent sources. It has been the writers' aim 

 to employ tl>o oldest, or most legitimate epithet, to which each 

 species is entitled ; they are aware, that in some instances, in this 

 respect, they are behind tlio mark; but regret this the less, that 

 the precedence of several names, at present in vogue, docs not, 

 in every case, appear to be satisfactorily established. 



The Catalogue QQVii^YWS, 3/53 genera, and upwards of 1,170 species, 

 certainly more than one- third of the whole British Coleoptera. 

 To this number, it is probable there are several others to be added, 

 for the limited time at the disposal of the writers has not enabled 

 them to examine the southern and western portions of the district. 

 From the want of materials for comparison, in the absence of 

 local works of a similar design, little can be said regarding the 

 distribution of the species oi Coleoptera included in the Catalogue, 

 further than as they occur within the limits to which it ia 

 confined. 'iMiere are scarcely any data for determining to what 

 degree the character of the rock formations of the district modify 

 the distribution of the Coleoptera; or, whether the supposed rela- 

 tions between these is not merely dependent on a false analogy. 

 The hygrometric condition of soils overlying rocks, together with 

 the nature of the herbage which they produce, exert a much more 

 sensible influence on insects than a difference of mineral consti- 

 tuents in the substrata, or even in the soils which result from their 

 decomposition. Wherever uniformity prevails, as in cultivated 

 districts, dry pastoral tracts covered with grass, or wide heathy 

 moors, insects will be found, whatever be the subjacent rock, to 

 bo equally deficient in species and in individuals. A varied 

 mechanical state of the soil, an alternation of moisture and dryness, 



