GEOGRAPHY OF THE GENERA. 95 



the happy chance, which may never recur, or only at 

 long intervals. 



Nor can I too impressively reiterate the importance 

 of noting both special localities, altitude, temperature, 

 season, flora, etc., as being all conducive to the widest in- 

 struction upon the subject. Indulging in the hope that 

 travellers will act upon these suggestions, and thus con- 

 siderably add to the value of what they may industriously 

 collect, we must patiently await until time brings it 

 about. 



Encouraging this expectation, I have summarily col- 

 lected, under their topical arrangement, the notices 

 which precede, but which are there arranged in the 

 generic order of the bees. 



From the information we thus possess, we learn that 

 some of our genera have an extremely wide diffusion, 

 and occur in countries where we might have expected 

 that other forms would have superseded them in the 

 offices they are ordained to fulfil. None of the schemes 

 for the geographical distribution of insects yet pro- 

 pounded, seem to curb the eccentricities of their range. 

 The regions proposed by Fabricius in his 'Philosophia 

 Entomologica/ they break through as readily as through 

 the concentric circles of the cobweb when this opposes 

 them : and all I can do is to present them as they offer 

 . themselves, with the remark that the occurrence of soli- 

 tary forms in certain localities are almost sure indica- 

 tions that allied genera would be found at hand were 

 they needfully sought. It will also be observed, that in 

 some places a parasitical genus, and its known sitos, 

 only, have been captured there. 



The following list will strongly show how totally our 

 genera of bees are unaffected by isothermal, isotheral, 



