Hydrophilus, IN THE

Short, A. E. Z. & McIntosh, C. E., 2014, Review of the Giant Water Scavenger Beetle Genus Hydrophilus Geoffroy (Coleoptera: Hydrophilidae) of the United States and Canada, The Coleopterists Bulletin 68 (2), pp. 187-198 : 188

KEY TO THE SPECIES OF HYDROPHILUS IN THE

UNITED STATES AND CANADA

1. Abdomen with glabrous region limited to the medial line of ventrites 3–5 ( Fig. 3 ). Prosternum divided into lateral halves for the reception of the anterior portion of the sternal keel. Dorsal surface sometimes appearing greenish. Eastern United States, eastern coast of Mexico, and extreme southeastern Canada........................... ................. Hydrophilus (Dibolocelus) ovatus

1′. Abdomen with glabrous region not limited to medial line of ventrites 3–5 ( Figs. 4–5 ). Prosternum strongly emarginated posteriorly but not divided into lateral halves. Dorsal surface never appearing greenish......................2

2. Specimens usually smaller (<32 mm). Collectively, the glabrous regions of ventrites 2–5 from a distinctive “kite” shaped glabrous region ( Fig. 4 ). Widespread from Mexico to Argentina, but not yet known from the Nearctic region ..... .............................. Hydrophilus (s. str.) ensifer

2′. Specimens usually larger (> 34 mm). Abdominal pubescence broad, not forming a “kite” shaped glabrous region on ventrites 2–5 ( Figs. 5–6 )..................................................3

3. Antennal cupule with little to moderate elongation ca. 1.2–2x as long as wide. Abdominal glabrous region as in Fig. 6 . Fifth protarsomere of the male expanded ( Fig. 2 ), but with a distinctly obtuse angle. Continental United States, southern half of Canada, and northern Mexico..................... Hydrophilus (s. str.) triangularis

3′. Antennal cupule greatly elongated ca. three times as long as wide. Abdominal gla- brous region as in Fig. 5 . Fifth protarsomere in males greatly expanded ( Fig. 1 ), the plate exhibiting a nearly right angle. Arizona, California, Texas, and Florida in the United States, Mexico, Central America, West Indies, and northern South America........................... ....................... Hydrophilus (s. str.) insularis

Figures

Figs. 3–6. Abdominal ventrites of Hydrophilus species, showing extent of medial glabrous region. 3) H. ovatus; 4) H. ensifer; 5) H. insularis; 6) H. triangularis.

Figs. 1–2. Hydrophilus species, male protarsi. 1) H. insularis; 2) H. triangularis.