A cytological survery of certain American species of the genus Gryllus Linnaeus, 1758, formerly Acheta, Fabricus, 1775, (Orthoptera: Gryllidae) and their hybrids.

• Main Author: Randell, Robert. L.
• Other Authors: Kevan, D. (Supervisor)
• Format: Others
• Language: en
• Published: McGill University 1960
• Subjects: Entomology.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112908

Mayr, Linsley and Usinger (1953) have defined three levels of taxonomic study; the first or alpha level dealing with the recognition and description of new species, the second or beta level dealing with the arrangements of these described species into the hierarchical system and the third or gamma level dealing with the study of infraspecific variation and the evolution of taxa. It is probably the general rule that, in any one group, progress is made by passing through these various levels in turn as they suggest in the following quotation.