The Hawaiian archipelago is a group of volcanic islands in the Pacific ocean. [Fig. 4.1] shows the relative locations of five of these islands. [Fig. 4.1] [Table 4.1] shows the size and age of these five islands and the total number of Mecyclothorax ground beetle species and their species density, on each island. Data for the island of Maui is shown as two distinct regions, West and Haleakalā. This is because they formed at different times from two separate volcanoes. [Table 4.1: island | area / km² | age of island / million years | total number of Mecyclothorax species | species density / number of species per km² - Hawai'i | 10433 | 0.4 | 30 | 0.003; Lāna'i | 364 | 1.3 | 3 | 0.008; Maui (West) | 443 | 1.3 | 27 | 0.061; Maui (Haleakalā) | 1440 | 1.1 | 116 | 0.081; Moloka'i | 673 | 1.9–1.8 | 43 | 0.064; O'ahu | 1545 | 3.7–2.6 | 20 | ...]