Notes on the Distribution of Insects^ SfC. 43 



Europe to the parallel of the Severn, and in America to near that 



of the Ohio There could not have been such a 



separating abyss between Northern Europe and Boreal America 

 as now divides them ; the sea, through a great part, must have 

 been a shallow sea, and somewhere, probably far to the north) 

 there must have been either a connexion or such a proximity of 

 land as would account for the transmission of a non-migratory 

 terrestrial and a littoral marine fauna. 



Mr. Wollaston says that, out of 482 species of Coleoptera 

 occurring in the Islands of Madeii-a, 201 are also found in Europe- 

 To account for this we must suppose one of two things, either 

 that the latter number of species have been introduced by acci- 

 dent as by man or by winds, or some similar cause ; or else that 

 these species have been in existence ever since the time when 

 Madeira formed part of the great continent. The latter supposi- 

 tion will certainly be preferred by all who have studied the great 

 changes which have taken place in the distribution of sea and 

 land even in the most recent Geological period. — Lubbock. 



In the family Cicindelidce, the species taken in this vicinity 

 evidently belong to a single genus. No species which can be 

 classed under Metjacephala, Omiis, xhnblychella, or Dromo- 

 chorus, have been discovered north of Lake Ontario ; of the last 

 genus, but one species occurs north of Mexico. We have eight 

 species of the genus Cicindela, but they ko closely^tesemble each 

 other in elytral characters, that the student encounters much 

 difficulty in determining a true form from a variety. 



With regard to 'our great family of €arubidce those that have 

 been collected must remain for the present untouched, until one 

 of our museums procure a foreign collection, contftining true 

 generic forms. 



Dr. LeConte of Philadelphia, has published an excellent classi- 

 fication of those occurring in the United States. We are indebted 

 to this gentleman's skill and energy for the present advanced 

 state of this branch of the Natural Sciences in America. Many 

 species of Dyticidoe inhabiting our waters, are described by him 

 in " Agassiz's Lake Superior. " 



SiLPHiD^ — Five species of the genus Necrophorus are now 

 known to occur north of Lake Ontario ; and of the three follow- 

 ing genera — viz : Necrodes, Oiceoptoma, ThanatoiJhilus, but one 

 species of each, whilst of the genus NecropMla we have four 

 species which are purely northern types. 



