32 



Fresh-water Biology 



{Continued from page 30) 



2 — Body ending in long median tail Sialis 



— Body ending in a pair of stout hook bearing prolegs 3 



3 — Lateral abdominal filaments with a tuft of tracheal gills beneath Corydalus 



— Lateral abdominal filaments with no tracheal gills beneath Ghauliodes 



4 — Bristles on back of thorax sessile Sisyra 



— Bristles on back elevated on tubercles Climacia 



» 



KEY TO THE FAMILIES OF ADULT AQUATIC BEETLES 



1 — Hind leg shorter than the foreleg; eyes divided Gyrinidae 



— Hind leg longer than the foreleg; eyes simple 2 



2 — Base of hind legs covered by coxal plates Haliplidae 



— Base of hind leg exposed 3 



3 — Antennae shorter than the palpi Hydrophilidae 



— Antennae longer than the palpi 4 



4 — Hind coxae broadly fused with metasternum Dytiscidae 



— Hind coxae free Parnidae 



For genera of adult beetles see Blatcheley's Coleoptera of Indiana. 



KEY TO THE GENERA OF MOLLUSCS 



1 — Shell univalve — Snails 2 



— Shell bivalve — Clams 11 



2 — No operculum • 3 



— With operculum 5 



3 — Shell patelliform, small, depressed Ancylus 



— Shell flatly coiled, whorls all in about same plane Planorbis 



— Shell spiral 4 



4 — Shell spire sinistral (to left; see fig. 3) Physa 



— Shell spire dextral (to right) Limnaea 



5 — Shell large, spire long, pointed; aperture one-third of length Pleuoceridae— 6 



— Shell large, not long and pointed; blobose. spire short, obtuse, aperture and spire 



about equal in length Viviparidae — 7 



— Shell small, length and width under 11 and 6.5 mm., variable in form 8 



6 — Shell conic; aperture subrhomboidal, prolonged into a short canal Pleurocera 



— Shell slender, ovate-conic, with color bands, whorls rounded, aperture rounded in 

 front, not prolonged into a short canal below Goniobasis 



{Continued on page 38) 



PLATE 13. MISCELLANEOUS INSECTS 



Adult Insects 



Figs. 1 to 5 represent families of adult beetles Qarva at plate 10): 1, Gyrinid^; 2, Hydrophilidae; 3 

 Dytiscidas; 4, Haliplidae; 5 Parnidae or Elmidae Fig. 13 is a spring-tail (Collembola). 



La 



rvae 



Genera Figs. 



Ghauliodes 8 



Glimacia (10)* 



Gorydalis (8)t 



Elophila lit 



Halesus 16 



Haliplus 7 



Genera 



Figs. Length Distr. 



Hydropsyche. . . 



Nymphula 



Peltodytes 



Philopotamus . . 



Siahs 



Sisyra 



15 

 12§ 



6 

 14 



9 

 10 



18 

 13 

 10 

 10 

 22 

 5 



G 

 G 

 G 

 G 

 G 

 E 



Waters 



lotic 



static 



static 



lotic 



static 



lotic 



• Differs by having dorsal set« inserted on tubercles. 



t Differs by haying white gill tufts under lateral abdominal filaments. 



t Another species of Elophila, lacking tracheal gills, lives in an ovate case on duck meat. (Lemna). 



§ Other species of Nymphula have branched tracheal gills. 



