198 AMERICAN HYMENOPTERA. 



In examining carefully this list we note the following pecu- 

 liarities : 



1. A scarcity of species in the following Canadian provinces and ter- 

 ritories : Yukon, Mackenzie, Athabasca, Keewatin, Manitoba, Labra- 

 dor, New Foundland, Prince Edward Island, Nova Scotia, and New 

 Brunswick. This may be due largely to lack of extensive collecting in 

 those portions of Canada. 



2. A scarcity of species in Greenland. This country is so far north 

 and its southern portion is so separated from Canada by water that it 

 probably has but few species anyway. 



3. A paucity of species in the greater part of the Great Central Plain 

 in the United States, especially in the most Southern States. This 

 scarcity is most strking in Florida, the most tropical state in the Union. 

 This part of the continent has received much attention from collectors, 

 and it is doubtful if any new species of Bombus will hereafter be found 

 in it. 



4. An abundance of species throughout that portion of North America 

 known as the Pacific Highland— from, and including a part of, Alaska 

 to the Isthmus of Panama. This is readily accounted for by the diver- 

 sified character of this part of the continent. The mountain ranges 

 and lower lands paralleling each other in long lines running north and 

 south make it possible for Boreal, Transition and Austral forms to 

 exist in close proximity over a widely extended territory. 



5. A similar abundance, though less marked, in the northern and 

 middle portions of the Highland of the Andes in South America. 



6. A paucity of species in Venezuela, Guiana and Bolivia probably 

 due to lack of collecting. 



7. A paucity of species in Paraguay, Uruguay, Argentina, and Chili, 

 due in part, perhaps, to lack of collecting, but probably more to an 

 actual scarcity. 



8. The subgenus Bombias is represented throughout Canada, except 

 in the following more northern and eastern sections: Yukon, Macken- 

 zie, Athabasca, Keewatin, Franklin, Labrador, New Foundland, Prince 

 Edward Island, Nova Scotia and New Brunswick. It is not present 

 in Greenland. It is represented in all the States of the United States, 

 except, perhaps, Maine ; also in Mexico, Central America and the fol- 

 lowing South American countries : Colombia, Venezuela, Ecuador, 

 Peru, Bolivia, Argentina and Chili. It is probably present also in 

 Guiana. If present in Brazil, it is probably confined to the mountain 

 ranges along the northern border. Its presence in Paraguay and 

 Uruguay is to be seriously doubted. 



9. The subgenus Bombus is present in every political division of the 

 New World listed above (including Bolivia, though not yet so reported) 

 and also in Greenland. 



