THE ENTOMOLOGIST. 241 



doubt will be discovoHMl in the norllKMii parts of tlic great 

 continent; but in Australia, New Zealand, and Afriea the 

 liombi are not found, if we cxce])t two or three European 

 species that have been observed to ])enetrate the north of the 

 latter country : as yet only five or six s])ecies have been dis- 

 covered in the new world, but the above enumeration will 

 show how widely they arc distributed. 



Of the species found in this country the majority are gene- 

 rally distributed, but a fow are extremely local, being con- 

 fined either to the mountainous or extreme parts of the 

 north, two species having hitherto been found in Shetland 

 only. 



During a series of fine, hot and dry summers these bees 

 multiply in great numbers, whilst a succession of cold and 

 wet seasons reduces them ; indeed, so greatly were those 

 species that build their nests on the surface of the ground 

 reduced by the continued rains of the sununers of 1859 — fiO, 

 tliat at this time they have by no means regained their usual 

 maximum of abundance. 



Their numbers are also greatly reduced by various ene- 

 mies, and jiarasitcs of their own ordcsr : field-mice and weasels 

 are said to devour the contents of their nests ; such a circum- 

 stance has not, however, fallen under my notice. Of insect- 

 parasites various species of Diptera are the most destructive . 

 to our native species : some nests are infested by species of 

 Volucella, which destroy a considerable portion of the larvaj. 

 A fossorial insect, MiUilla Eurojjea, is occasionally found, in 

 the larva state, feeding on the young brood of these bees : 

 M. Drewsen reared from a nest of liombus Scrimshiranus, 

 taken near Copenhagen, no less than seventy-six of this 

 Mutilla ; the parasite is, however, too rare in this country to 

 cause any great diminution of their numbers. Acari occasion- 

 ally render their nesls almost unt(;uantable by their numljers; 

 they devour the honey and wax. 1 have also fre({uently 

 found Coleoptera in nests, but not in such numbers as to 

 render it at all probable that they cause any great destruc- 

 tion of the inhabitants ; Anobium ))anicinm, Anlhero])hagus 

 nigricornis, and one or two sj)ecies of Brachelytra, arc among 

 the number. 



The nests of the 13ombi are constructed either on the sur- 

 face or under ground : such is the normal habit of the sj)ecies, 



