44 ROEBUCK : ON YORKSHIRE ACULEAtA. 



humble-bees, particularly Boinbus liuorum, abounded in immense 

 profusion, while as to the ants, Mr. Smith's remarks will be found 

 below (see My r mica scabrinodis). 



My experience corroborates Mr. Smith's view of the relative 

 abundance of social and solitary aculeata, especially bees : often 

 have I wondered that I have not seen the air darkened with the 

 iinmense clouds of Ajithophora noticed in the south, and that I 

 have so seldom met with examples of the so-called common 

 species of the genera Osmia, MegacJiile, Anthidiian, Cheiostoma, 

 &c., while on the other hand Humble-Bees (Bombus), Wasps 

 ( Vespa), and Ants (Formica and Myrmica) abound in every part 

 of the county. Tables of geographical distribution show that the 

 various genera of solitary hymenoptera are of southern range, 

 and abound most in species and individuals in warm climates, 

 while on the other hand the Humble-Bees are decidedly northern 

 in their range, penetrating far into the Arctic Regions and only 

 appearing in the Tropics in diminished numbers. Why this 

 should be so has yet to be ascertained, but meanwhile the fact 

 remains that our county is, as regards its hymenoptera as well as 

 in geographical position, decidedly of northern tendency. 



Tribe HETEROGYNA—Ants. 



The British Ants are described in Smith's ' Catalogue of 

 British Fossorial Hymenoptera, Formicidse, and Vespidse, in the 

 collection of the British Museum,' 1858 (6/-), to the number of 

 8 genera and 33 species, distributed among the families Formicidx, 

 Poneridcs, Myrmicid(2, and Mutillidcz. 



A paper by Mr. Smith, published in the E.M.M. for July 

 1865 (ii. 28-30), will be found very useful and suggestive. The 

 number of British species given in the most recent enumeration 

 (F. Smith's 'Catalogue of British Hymenoptera; Aculeata,' 187 1, 

 published by the Ent. Soc.) is 35 species in 12 genera and the 4 

 families before mentioned : increased to 36 species by the 

 discovery of a new form, Ponera tarda, Charsley (E.M.M. 1877, 

 xiv. 162). For comparison, Bold's Catalogue for Northumberland 

 and Durham includes 13 species. 



Trans. Y.N.U.,1877. Series D 



