Match the Hatch (ver 2.0)

Identify Major North American Mayfly Species from Description of the Insect

NOTES

It is preferable to examine several individuals of the same species and to use average values for keying the species. However, since the nymph passes through a number of instars between egg and adult, only the largest individuals should be used. (Preferably only those exhibiting signs of emergence.)

The more data you provide, and the more accurate your data, the more likely the results will be correct!

Required Data in red, Optional Data in blue.

DEVELOPMENTAL STAGE

nymph
subimago (dun)
imago (spinner)

NYMPH LIFESTYLE (If nymph)

Crawler
Clinger
Burrower
Swimmer

LENGTH OF BODY in mm (from front of head to end of abdomen.)

(If insect is measured in inches, use the following calculator to convert to mm)

Convert inches to millimeters:

Enter length in inches and 64ths of inches: and /64 equals mm.

COLOUR OF BODY:

Light Gray to Black
light gray
light gray with dark markings on the back
olive gray with brown markings
tan gray
gray with brown markings
medium gray
gray with brown rings
dark gray
brownish gray with dark brown markings
dark brownish gray with darker mottling on back
brownish black
dark brownish black
black
Brown
dark blackish brown
blackish brown
dark grayish brown on top, light brown underneath
dark grayish brown with light rings
dark grayish brown
grayish brown
varies from grayish brown to yellow with purplish brown markings on back
dark brown
dark brown; segments 2-6 white
dark brown with wide pale margins so as to appear ringed
dark brown with light rings in abdomen
dark brown thorax, medium brown abdomen
dark brown, yellowish underneath
dark brown on top, pale brownish olive underneath
dark chestnut brown
dark reddish brown
mottled brown on top, maroon underneath
males: brown, females: light olive
brown on top, amber underneath
brown with orangish or yellowish cast, heavily freckled or mottled
reddish brown
males: reddish brown, females: light greenish tan
light translucent reddish brown
reddish brown with olive cast
brownish with olive tint
chocolate brown with yellowish cast
brown
medium brown
brown with light markings
light brown
dark olive brown
medium olive brown
light olive brown with orangish cast
tannish brown
males: yellowish brown, females: yellowish olive
yellowish brown
yellowish brown, segments 2-7 semitransparent
Greens and Olives
brownish olive and yellow
green with dark brown rings-dark brown markings only on dorsal in freshly hatched duns
pale yellowish green
greenish olive
medium greenish olive
dark brownish olive
dark olive
medium olive
various combinations of olive, tan and yellow
females: olive with slight yellowish cast, males: yellowish orange with a slight olive cast
grayish olive with brown bands
light olive
females: light olive, males: brown
olive with a slight yellowish cast
females: yellowish olive, males: yellowish brown
pale yellowish olive
pale yellowish olive with brown markings on back
Amber and Yellow
amber with distinct olive cast
amber with medium brown markings
amber with dark brown markings
brownish yellow
brownish olive and yellow
orangish yellow
yellow
yellowish with dark brown markings
yellowish with distinct olive cast
olive yellow
various combinations of olive, tan and yellow
varies from yellow to grayish brown with purplish brown markings on back
grayish yellow with dark brown markings
yellowish with purplish brown markings on back
bright, light olive yellow
pale yellow, brown markings on back
males: yellowish orange with a slight olive cast, females: olive with slight yellowish cast
creamy yellow with brownish markings
Pink, Ginger to Tan
grayish pink with brown markings on back
tan mottled with brown
tan
various combinations of olive, tan and yellow
tannish with an amber cast
females: light greenish tan, males: reddish brown
light grayish tan with tiny dark brown speckles
light grayish tan
cream to light grayish tan
Cream to White
light cream, brown markings on thorax
pale yellowish-cream
cream
cream to light grayish tan
creamy white
white

NUMBER OF TAILS:

2
3

COLOUR OF TAILS:

Gray to Black
very light gray
light gray
gray with brown markings
medium gray
gray, banded
dark olive gray
dark gray
Brown
dark grayish brown
dark brown
dark brown with black bands
brown with black bands
brown with dark joinings
mottled brown
brown
medium brown
grayish brown
light brown
dark olive brown
medium olive brown
light olive brown
yellowish brown
pale yellowish brown
Green to Olive
dark brownish olive
brownish olive
green and brown
olive
light olive
light olive with dark specks
light olive with brown rings
Amber to Yellow
amber mottled with brown
amber with dark bands
amber with brown bands
amber
yellow
yellow mottled with brown
Ginger to Tan
ginger
tan with dark specks
tan with dark brown mottlings
tan with dark brown at joinings
tan, mottled with brown
tan, mottled
tan
light tan
light tan with brown at joinings
Cream to White
cream
light gray or whitish
whitish with brown at joinings
white

HIND WINGS (Dun and Spinner Only):

absent
minute with pointed costal projection
minute with obtuse costal projection
tiny
small
medium
large
large with dark staining to rear edge
large with costal projection
large with costal projection followed by shallow depression
very large (half the size of the fore wing)

WING OR WINGPAD COLOUR:

Gray to Black
light gray
light gray with yellowish tinges on the leading edge
light gray with distinct olive cast and brown mottlings
light yellowish-gray, spotted with brown
light yellowish-gray
yellowish-gray
smokey gray with olive reflections
tan gray
gray with brown markings
medium gray
gray, heavily spotted with dark brown
slate gray with white veins
slate gray
slate gray washed with brown
dark slate gray
dark gray
dark gray, paths of veins and cross veins white
dark gray- almost black
dark brownish-gray
brownish black
dark brownish black
black
Brown
blackish-brown
dark brown
dark mottled brown
dark brown freckled with light brown and yellow
Olive to Yellow to Tan
brownish olive
tannish olive mottled with dark brown
yellow
yellow, mottled
tan, mottled
Cream to Clear
cream with brown flecks
creamy, mottled
hyaline -whitish
hyaline (clear) with distinct reddish brown veins
hyaline (clear), heavily spotted with dark brownish black
hyaline (clear), heavily mottled with dark brown
hyaline (clear), dark brown splotches on leading edge
hyaline (clear), slight dark mottlings
hyaline (clear) mottled with light brown
hyaline (clear)

LEG COLOUR:

Gray to Black
very light gray
light gray
gray shading to dark gray brown
gray with dark markings
gray with brown markings
dark gray
brownish black
dark brownish black
Brown
dark grayish brown
brown shading to dark brown
mottled brown
reddish brown fading to white
brown
tan, forelegs brown
medium brown
banded light and dark brown
light brown
dark olive brown
medium olive brown
yellowish brown
pale yellowish brown
Olive to Amber to Yellow
brownish olive
olive
light olive
light olive with dark specks
light olive with brown bands
light olive shading to brown
light yellowish olive shading to brownish green
tannish olive
amber mottled with brown
amber with dark bands
amber, shading to brown
amber
pale amber to white banded with brown
yellow
yellow with brown markings on forelegs
yellowish, forelegs brown
Tan to Cream to White
olive tan
tan shading to brown
tan with dark markings
tan with dark brown mottlings
tan, mottled with brown
tan, forelegs brown
tannish banded with brown
tan
pale tan
tannish cream
cream, forelegs brown
cream, forelegs brown; feet white on females
cream with tan markings
cream with brown markings
light gray or white
white

REGION:

East (N. America)
MidWest (N. America)
West (N. America)

FOUND IN WHICH TYPE OF WATER:

Dead
Slow
Medium
Fast

MONTH OF HATCH:

January
February
March
April
May
June
July
August
September
October
November
December

WEEK OF MONTH:

First Week Second Week Third Week Fourth Week

TIME OF EMERGENCE:

Around dawn.
Around midmorning.
Around noon.
Around midafternoon.
Around dusk.
Around midnight.
Between midnight and dawn.

SPINNER FALL:

Around dawn.
Around midmorning.
Around noon.
Around midafternoon.
Around dusk.
Around midnight.
Between midnight and dawn.

last modified 30/6/07

This program is still under development. Please report errors to: bruce@fishermonk.com