The species of Sialis are not known in Ohio. The following are possibilities for Ohio.
1. Mandibles each with 3 subapical teeth . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialis americana*
Mandibles each with 2 subapical teeth, minute 3rd tooth sometimes present . . . . . . . . . . . . . 2
2. Venter of abdomen with distinct cross bands or solidly dark with pigment . . . . . . . . . . . . . . . 3
Venter of abdomen light in color lacking distinct cross bands, or with incomplete bands . . . . . 6
3. Background color of head and thorax dark with distinct lighter markings on head and pronotum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Background color of head and thorax with faint markings on head and pronotum . . . . . . . . . 5
4. Labrum with a snout-like front; venter of te abdomen with all but last segment darkened completely, a narrow white line along the lateral edges . . . . . . . . . . . . . . . . . . . . . . Sialis iola
Labrum lacking a snout as above; venter of abdomen with dark bands incomplete at the edges of each segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialis hasta
5. Pronotum with only posterior pronotal medial spot visible, lateral elliptical spots large and ovoid on a dark background; labial marginal setae, usually 12 per side; meso- and metanotal patterns as (P1.XI, C). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sialis joppa
Pronotum with pronotal medial spots faint; labral marginal setae usually 15 per side; meso- and metanotal patterns as (P1.X., C). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialis aequalis
6. Dorsum of abdomen with markings forming an anchor-like figure on each segment; pronutum with rectangular light area at center. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialis vagans
Dorsum of abdomen with usual chevron markings; pronotum not as above. . . . . . . . . . . . . .7
7. Pronotum with small, dark elliptical pronotal spots, median protion light; venter of the abdomen with cross bands incomplete at midline or absent. . . . . . . . . . . . . . . . . . . . . Sialis infumata
Pronotum without dark elliptical pronotal spots, pattern may be indistinct; venter of abdomen usually white. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Head with darkened markings' pronotal medial spots dark; mesonotum and metanotum as (P1. XII., B., C.). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialia itasca
Head with patterns faint; pronotal medial spots barely visible if at all; mesonotum and metanotum not as above. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sialis mohri
* Sialis americana reported in Ohio (near Kent) by Ross (1935), but not by Canterbury (1978).
Key to Sialis Nymphs Species