Small black ant  (Lasius niger)

Cocoon: a sheath of silk, which is spun around the pupae of some insects (a pupa is a stage in an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis).
Colonies: a group of organisms living together, individuals in the group are not physiologically connected and may not be related, such as a colony of birds. Another meaning refers to organisms, such as bryozoans, which are composed of numerous genetically identical modules (also referred to as zooids or 'individuals'), which are produced by budding and remain physiologically connected.
Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Pupae: stage in an insect's development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.

1. National Biodiversity Network Species Dictionary (Jan 2003):
   http://www.nhm.ac.uk/nbn
   
2. Domisthorpe, H. (1927) British ants. George Routledge and Sons, Ltd., London.
   
3. Skinner, G. J. (1987) Ants of the British Isles. Shire Natural History. Shire publications Ltd., Aylesbury.
   
4. Sterry, P. (1997) Complete British Wildlife photo guide. Harper Collins Publishers, London.