. Fresh-water biology. Freshwater biology. 938 FRESH-WATER BIOLOGY 7 (4) Last abdominal segment elongate pyramidal, and furnished with a mid- ventral line of hairs Gyretes. 8 (3) Hind legs longer than the fore; eyes two 9 9 (14) Base of the hind legs covered by broad overlapping coxal plates. Family Haliplidae 10 10 (13) Coxal plates concealing only the three basal segments of the abdomen; last segment of palpi shorter than the preceding segment. 11 11 (12) Pronotimi widest before the middle. Brychius. 12 (11) Pronotmn widest at the rear end. Haliplus. 13 (10) Coxal plates concealing all but t
. Fresh-water biology. Freshwater biology. 938 FRESH-WATER BIOLOGY 7 (4) Last abdominal segment elongate pyramidal, and furnished with a mid- ventral line of hairs Gyretes. 8 (3) Hind legs longer than the fore; eyes two 9 9 (14) Base of the hind legs covered by broad overlapping coxal plates. Family Haliplidae 10 10 (13) Coxal plates concealing only the three basal segments of the abdomen; last segment of palpi shorter than the preceding segment. 11 11 (12) Pronotimi widest before the middle. Brychius. 12 (11) Pronotmn widest at the rear end. Haliplus. 13 (10) Coxal plates concealing all but the last of the ventral abdominal seg- ments; last segment of palpi longer than the preceding seg- ment. Peltodytes. 14(9) Base of the hind legs exposed. ... 15 15 (48) Antennae shorter than the palpi; legs usually with swimming fringes. Family HvDROPHiLiDAE. 16 16 (23) Scutellum wanting or indistinct or very small and scalelike. Posterior femora subcyhndrical and not noticeably widened in the mid- ^ ^. ji .-L J T_ 1 - 1 iTG. 1392. Diagram 01 the ventral die; pro thorax narrowed behind, aspect of a diving beetle, Capiotomus narrower than the elytra. The i^^^rogatus: a, antenna; i, mouth; n 1 J. ^' 'â ⢠coxal cavities for the fore and species are small, elongate, middle legs; d, labial palpi; e. eye; roughly sculptured, greyish or J. maxillary palpi; 5, lateral margin 111 1 J n V. ⢠1 ot the prothorax; h, epipleuron of nearly black, and usually tinged the wing cover (elytron); ;, pros- With bronze and metallic col- ternal process; /, metastemal fork;. 17 (20) 18 (19) 19 (18) ors. ... . 17 ScuteUum indistinct, or apparently want- ing; if at all evident it is distinctly triangular and acute. Species from 1-2 mm. long. 18 Pronotum without striae; maxiUary palpi k, hind coxa with /, the inner lam- ina; p, the coxal process and g, the coxal notch; r, trochanter of the hind leg; s, femur; t, tibia; u, hind tarsus of five joints; j, 2, 3, 4, ?, (5, ventral abdominal segments, 5^^
Size: 991px × 2522px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
