Kingdom: Animalia 
Phylum: Arthropoda
Class: Insecta 
Order: Hymenoptera
Family: Apidae
Subfamily: Apinae 
Tribe: Bombini 
Genus: Bombus
Species: Four species in NZ. Bombus terrestris, Bombus ruderatus, Bombus hortorum, Bombus subterraneus.
Common name: Bumble bee'

The four species of bumblebee (Bombus) were introduced from England in 1885 and 1906 for pollination and seed production of red clover. It was the first time that insects had been introduced into a county specifically to pollinate a particular flower. Four species were imported before it was realised that bumblebees tongue length differs from species to species. The widest spread species in New Zealand, is the the large earth bumblebee Bombus terrestris was found to have the shortest “tongue” rendering it less effective for pollinating red clover. The other three species have the longest “tongues”. Their longer tongues can reach inside red clover flowers, which the shorter-tongued honeybees cannot do although they are excellent pollinators of the smaller white clover flowers. Compared with honeybees all bumblebees have longer tongues.
If a large earth bumblebee cannot reach the nectar in a flower it will often bite a hole in the base of the flower bypassing all the pollination specialisations of the flower. Other insects on future visits will use the same hole hence pollination will not occur.
Bumblebees are sometimes used to pollinate greenhouse and orchard crops. Only females (queens and workers) have a sting, but they are not aggressive and usually sting only if disturbed or handled roughly.
Bumblebees make their nests in holes in the ground such as rabbit burrows, or where they can burrow, such as in a compost heap. They also use hollow spaces in buildings. The cells are less regular than those made by honeybees.

There are four species in New Zealand see descriptions below.

Bombus terrestris: They are characterized by their white-ended abdomens and look apart from their yellowish bands being darker in direct comparison to other species. http://www.terrain.net.nz/friends-of-te-henui-group/local-flies/bumble-bee-bombus-terrestris.html

Bombus terrestris
Bombus terrestris-4.JPG

Bombus subterraneus: Thorax back to the wings is yellow. The hair is long.see http://www.biolib.cz/en/image/id17926/

Bombus ruderatus.In comparison with other bumblebee species, the large garden or ruderal bumble bee has a long face and tongue; these are adaptations for feeding on long-tubed flowers. They are black, with two yellow bands on the thorax, a single yellow band on the abdomen and a white tail
See http://www.biolib.cz/en/image/id132149/

Bombus hortorum: This is a large bumblebee, which has a fairly 'scruffy' appearance with long hair. It is a yellow, black and white banded species, with a long head. The tongue, which is as long as the body, is the longest of all bumblebees. Three 'castes' occur within bumblebee nests, a 'queen' (the reproductive female), 'workers' (non-reproductive females) and males. All three castes are broadly similar in appearance, but males can be distinguished as they lack stings and have longer antennae than the females. See http://www.biolib.cz/en/image/id126171/ 
Bombus hortorum.jpg

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0