121a (104) Antennae 3- or 4- segmented, but much shorter than head,
usually hidden in cavities beneath the eyes. Hind legs oar
like, heavily fringed with hairs and used like a pair of oars
for swimming underwater [122]
121b Antennae 4-segmented, as long as or longer than head and
visible from above. Hind legs like middle legs, long but
not oar-like. Walking on water surface [124]
122a (121) Front legs with end segment modified into scoops (held
like spoons beneath the mouth); middle legs, long and thin.
Eyes red. Body flattened; adults with numerous fine, black
lines across back. Temporary pools and ponds, fresh to saline.
Water boatmen Fam. CORIXIDAE Trichocorixa reticulata (Guerin-Meneville)
122b Front legs resembling middle legs, without scoop-like ends. Body
not compressed; back arched. Hemielytra (wing covers) trans-
parent. Back-swimmers Fam. NOTONECTIDAE [123]
123a (122) Small (5 - 9 mm); with 3-segmented antennae. Long hairs
present along centerline of back, but hemielytra without hairs
Buenoa pallipes (Fabricius)
123b Larger and stouter (8 - 17 mm) with 4-segmented antennae. Without
long hairs along back, but hemielytra with scattered, fine
hairs Notonecta indica L.
124a (121) Tip end of tarsal segment (end part of leg) extends
beyond the claws as a cleft pad; tarsi 2-segmented. Water
treaders and striders [125]
124b Paired claws on tarsi are at very end (apical); tarsi 2- or
3-segmented [126]
125a (124) Middle pair of legs arising midway between front and
hind pairs. Femora (first long segment of leg) of hind legs not
extending beyond end of abdomen. Small (to 3 mm), dark,
gregarious insects skating on pool or pond surface
Fam. VELIIDAE Microvelia vagans White
125b Middle pair of legs arising closer to hind legs than front legs.
Hind femora extending well beyond end of abdomen. Insect
usually larger than 5 mm long. Marine. Water striders [Note D]
126a (124) Tarsi of hind legs are 2-segmented. Body stout, densely
coated with short, velvety hairs. Velvet water bugs
Fam. HEBRIDAE Merragata hebroides White
126b Tarsi of hind legs 3-segmented. Body slender, without velvet
covering [127]
127a (126) Small, oval, flattened, brown or black and white bugs
found along the shore of streams and ponds
Fam. SALDIDAE Saldula spp. (8 endemic to Hawai`i)
127b Small (under 5 mm), slender greenish or yellowish bugs. Some
adults without wings (apterous). Found on water surface
at the shore of ponds and wetlands Fam. MESOVELIIDAE (3 spp.)
Cavaticovelia aaa (Gagne & Howarth) [cave dwelling species]
Mesovelia amoena Uhler
Mesovelia mulsanti White [common in lo`i]
