Hex Mayflies
Hexagenia limbata
The famous nocturnal Hex hatch of the Midwest (and a few other lucky locations) stirs to the surface mythically large brown trout that only touch streamers for the rest of the year.
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This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
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Insect Order Diptera (True Flies)
This incredibly diverse order holds tens of thousands of species. They are the "true flies" with two wings, and they have complete life cycles (larva to pupa to adult). Beyond that they have little in common.
The most important family is Chironomidae, the midges. The craneflies of Tipulidae and the related families may also be important, as may be several of the others in the right place and time.
The most important family is Chironomidae, the midges. The craneflies of Tipulidae and the related families may also be important, as may be several of the others in the right place and time.
Specimens of True Flies:
1 Female Adult
This midge and several like it, including a male I also photographed, hatched from larvae which were living in some fine mud I'm using as substrate in my bug-rearing aquarium. This one flew away before I could photograph it on the ruler, but it would have measured slightly smaller than the male.
10 Adults
I'm not fully confident in the ID on this one. I couldn't see for sure that there are two equal pads under the tarsal claws instead of three, but it seems that way. The antennae are 4-segmented, although I'm not sure if the last segment counts as a "segment" rather than a style@ or arista sticking off the third segment. It has three ocelli. The key characteristics generally point to Empididae except "Vein R4+5 usually branched." That vein certainly isn't branched in this specimen, but the key does say "usually."
This extremely tiny fly was puzzling to identify. I collected it from a sparse mating swarm just above the surface of the river. It just doesn't have the "look" I'm used to seeing in Chironomids, but the key characteristics in Merritt, Cummins, & Berg point that way.
-Maxillary palp apparently with 4 segments, antenna with 6
-I can't see any ocelli and wing venation doesn't seem to match Axymyiidae
-Costa definitely ends at or near apex of the wing (pictured)
-Obvious characteristics and wing venation rule out a few other things
-Simuliidae seems like a possibility due to the broad wings, but bugguide says they're supposed to have more antennal segments (eleven, though a different source says some have ten, at least in the Southern Hemisphere).
-Postnotum with median longitudinal groove (pictured) rules out Ceratopogonidae
So my guess is some kind of chironomid from a genus that doesn't have the classic midge look. There are some like that.
-Maxillary palp apparently with 4 segments, antenna with 6
-I can't see any ocelli and wing venation doesn't seem to match Axymyiidae
-Costa definitely ends at or near apex of the wing (pictured)
-Obvious characteristics and wing venation rule out a few other things
-Simuliidae seems like a possibility due to the broad wings, but bugguide says they're supposed to have more antennal segments (eleven, though a different source says some have ten, at least in the Southern Hemisphere).
-Postnotum with median longitudinal groove (pictured) rules out Ceratopogonidae
So my guess is some kind of chironomid from a genus that doesn't have the classic midge look. There are some like that.
One of the only real benefits I've got from my rearing aquarium so far is that I've had quite a variety of midges emerge, giving me a chance to photograph these fragile little insects which are otherwise really hard to transport in photogenic form. This one recovered from being gassed and flew away before I could photograph it on the ruler, but it was very small, around 1.5mm.
This is a small cranefly species.
Midges of the family Chironomidae are probably the most widespread aquatic insect in the world.
1 Male Adult
This midge and several like it, including a female I also photographed, hatched from larvae which were living in some fine mud I'm using as substrate in my bug-rearing aquarium.
5 Pupae
10 Larvae
I don't see a lot of green Chironomidae larvae in my samples, so I photographed this one.
This relatively large, olive-colored midge larva was very abundant in my samples from this little creek in the mountains.
These larvae were all over the submerged rocks in a small mountain stream in the Washington Cascades, tightly adhering to the rocks in their flat, half-disk-shaped cases.
8 Streamside Pictures of True Flies:
The least welcome sign of spring
In this picture: True Fly Family Culicidae (Mosquito).
Several craneflies formed a mating cluster here in a dark rootwad along the bank of a large limestone trout stream.
In this picture: True Fly Family Tipulidae (Crane Fly).
Testing the limits of my dedication to producing insect pictures, I held still for several shots with these mosquitoes on my wrist, trying to get one with good focus.
In this picture: True Fly Family Culicidae (Mosquito).
A dense cloud of extremely tiny flies hovers close over the river.
In this picture: Insect Order Diptera (True Fly).
A lone fly rests upon a rock in the middle of a little brook trout stream that's catching the late afternoon sun.
In this picture: Insect Order Diptera (True Fly).
Cases made by larvae of some sort of Chironomid midge, which I photographed with my bug kit back in the studio.
In this picture: True Fly Family Chironomidae (Midge).
Thousands of midges swarming over a sunny pool.
In this picture: True Fly Family Chironomidae (Midge).
9 Underwater Pictures of True Flies:
This is my favorite underwater picture so far. It shows a bunch of Simuliidae (black fly) larvae clinging to a rock and swinging in the fast current. There are also at least four visible mayfly nymphs, probably in the family Baetidae.
In this picture: Mayfly Family Baetidae (Blue-Winged Olive) and True Fly Family Simuliidae (Black Fly).
The white blotches on this rock are Leucotrichia caddisfly cases, and the wispy tubes are cases made by a type of midge.
Some large Ephemerella mayfly nymphs cling to a log. In the background, hundreds of Simuliidae black fly larvae swing in large clusters in the current.
The strange tubes all over this rock house tiny midge larvae.
This isn't really an underwater picture, but a picture taken into my aquarium of midge larvae which lived in the silt I used for substrate. Each larva has a little tower of detritus built up along the bottom, while the bare larva waves around from the top.
In this picture: True Fly Family Chironomidae (Midge).
In this picture: Insect Order Trichoptera (Caddisfly) and True Fly Family Chaoboridae.
The large caddisfly case (really less than 1/2 inch) is a Brachycentridae larva. The other cases are actually the protective sheaths of black fly (Simuliidae) pupae. The two antler-like pieces sticking out of each one are not legs, but antennal sheaths.
Discussions of Diptera
getting midges down
9 replies
Posted by CaseyP on Dec 8, 2007 in the family Chironomidae
Last reply on Jan 17, 2018 by Ummm
says here midge pupae rise in the water and struggle in the film to become adults. my imitations are so small that they don't seem to go down very far in order to rise--ike a wet fly might at the end of the swing. any ideas? or am i fishing them wrong?
Clusters of midges and the Griffith's Gnat
35 replies
Posted by Troutnut on Apr 10, 2007 in the family Chironomidae
Last reply on May 22, 2015 by Taxon
This is a spin-off from a tangent in another topic which seems worthy of its own thread.
I wrote about the midge I photographed:
Gonzo replied:
Those are the explanations I've heard, too, but I'm skeptical of both. I'm not doubting the effectiveness of the Griffith's Gnat; I just think people have traditionally stretched the bounds of credibility when trying to explain a fly's success in imitative terms, and this is one of the more prominent examples.
Has anybody here seen a cluster of midges on the water? I haven't. I have seen midges thickly grouped on rocks next to the water, and I don't doubt that they occasionally fall off of there, and probably sometimes two are three are clinging to each other. I've also seen early-season stoneflies balled up with each other in an opaque little (presumably mating-related) clump on a midstream boulder, and I wouldn't be surprised if some midge species do something like that too. But trout don't see balls of midges floating around very often on any stream I've ever observed. Has anyone experienced that?
In either case, I can't see something so opaque as a Griffith's Gnat effectively imitating what would surely be a loose ball of gangly entangled midges. You would have to roll them around in your fingers for a while to goo them together so solidly.
I just can't see the herl and hackle imitating, or even suggesting, a loosening pupal shuck. Shucks don't get that loose. They trail behind length-wise; they don't balloon to the sides. And they aren't pointy. Of course I'm sure Schwiebert knows all that and was just trying to add an idea to the mix of explanations, but I do find that one as far-fetched as the others.
Here's another far-fetched guess: maybe the hackle and refractive trickery in the surface film reduce the perceived thickness of the fly and it passes for a single midge pretty well. This could be tested in an aquarium but it's late and I'm feeling lazy.
I think it's more likely that when trout take a Griffith's Gnat they're only looking for (at most) the right general size and color. It's not as fun, but sometimes things are really that simple.
I wrote about the midge I photographed:
I'm not sure how a griffith's gnat is supposed to imitate such a thing
Gonzo replied:
Schwiebert's theory was that when it was awash in the film, the herl and halo of hackle suggested the loosening pupal shuck around the dark body of the emerging midge. Others have speculated that it imitates a cluster of midges. Both theories are reasonable, I suppose, depending on the size of the Griffith's Gnat that is effective relative to the size of the actual midge. Like many anglers, I just know that it does work. :)
Those are the explanations I've heard, too, but I'm skeptical of both. I'm not doubting the effectiveness of the Griffith's Gnat; I just think people have traditionally stretched the bounds of credibility when trying to explain a fly's success in imitative terms, and this is one of the more prominent examples.
Has anybody here seen a cluster of midges on the water? I haven't. I have seen midges thickly grouped on rocks next to the water, and I don't doubt that they occasionally fall off of there, and probably sometimes two are three are clinging to each other. I've also seen early-season stoneflies balled up with each other in an opaque little (presumably mating-related) clump on a midstream boulder, and I wouldn't be surprised if some midge species do something like that too. But trout don't see balls of midges floating around very often on any stream I've ever observed. Has anyone experienced that?
In either case, I can't see something so opaque as a Griffith's Gnat effectively imitating what would surely be a loose ball of gangly entangled midges. You would have to roll them around in your fingers for a while to goo them together so solidly.
I just can't see the herl and hackle imitating, or even suggesting, a loosening pupal shuck. Shucks don't get that loose. They trail behind length-wise; they don't balloon to the sides. And they aren't pointy. Of course I'm sure Schwiebert knows all that and was just trying to add an idea to the mix of explanations, but I do find that one as far-fetched as the others.
Here's another far-fetched guess: maybe the hackle and refractive trickery in the surface film reduce the perceived thickness of the fly and it passes for a single midge pretty well. This could be tested in an aquarium but it's late and I'm feeling lazy.
I think it's more likely that when trout take a Griffith's Gnat they're only looking for (at most) the right general size and color. It's not as fun, but sometimes things are really that simple.
Midges
10 replies
Posted by Goose on Oct 24, 2006 in the family Chironomidae
Last reply on Jan 14, 2015 by Martinlf
Hi Jason & Gonzo! I did well over the weekend by fishing some midge pupa imitations as nymphs and in the film. Where does one find midge larva to inspect for pattern imitation? I fished the pupas and larvas on 5x tippet and it seemed to work well. Do midges live in the silt or on the bottom of rocks, etc.? I have the book by Ed Koch and ?, the other name escapes me for the moment, but it doesn't exactly say where they are found. Midges are about the game in in town during the winter months so I thought I'd learn a little about them. Thanks
Thank you for the nice quality pictures.
1 replies
Posted by Mushroom on Sep 22, 2014 in the family Simuliidae
Last reply on Sep 23, 2014 by Troutnut
Thank you for the nice quality pictures. I want to use your picture in my personal presentation in my science class. Would you mind this? I will wait your answer. thank you.
Life cycles and hatches
3 replies
Posted by Leahdanger on Mar 7, 2014 in the family Chironomidae
Last reply on Mar 9, 2014 by Entoman
Hi,
I am trying to identify the life cycle of a few aquatic insects in eastern British Columbia. Specifically, I want to know if the species I collected in the fall (Aug-Oct) are a different hatch from the species I collected in the spring (April-May). Does anybody know when the following species lay eggs, die, and hatch: amphipods (Hyalella aztecha), chironomids, leeches, mayflies (Leptophlebiidae paraleptophlebia, Baetida sp.), and caddis flies (Oxyethira sp., Hydropsychidae arctopsyche)? For my purposes, knowing the general life cycle of amphipods and chironomids would be great.
Thanks much for your help!
Leah
I am trying to identify the life cycle of a few aquatic insects in eastern British Columbia. Specifically, I want to know if the species I collected in the fall (Aug-Oct) are a different hatch from the species I collected in the spring (April-May). Does anybody know when the following species lay eggs, die, and hatch: amphipods (Hyalella aztecha), chironomids, leeches, mayflies (Leptophlebiidae paraleptophlebia, Baetida sp.), and caddis flies (Oxyethira sp., Hydropsychidae arctopsyche)? For my purposes, knowing the general life cycle of amphipods and chironomids would be great.
Thanks much for your help!
Leah
Start a Discussion of Diptera
References
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
- Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.
Insect Order Diptera (True Flies)
Taxonomy
Family in Diptera
AthericidaeWatersnipe Flies
3
13
BlephariceridaeNet-Veined Midges
0
0
Chaoboridae
0
1
ChironomidaeMidges
28
140
CulicidaeMosquitoes
1
6
Dixidae
2
16
Dolichopodidae
2
20
Empididae
1
10
LimoniidaeLimoniid Crane Flies
5
21
PediciidaePediciid Crane Flies
1
9
Psychodidae
1
8
PtychopteridaePhantom Crane Flies
2
10
SimuliidaeBlack Flies
5
24
TipulidaeCrane Flies
11
56
Family in Diptera: Athericidae, Blephariceridae, Chaoboridae, Chironomidae, Culicidae, Dixidae, Dolichopodidae, Empididae, Limoniidae, Pediciidae, Psychodidae, Ptychopteridae, Simuliidae, Tipulidae
24 families (Axymyiidae, Canacidae, Ceratopogonidae, Coelopidae, Corethrellidae, Cylindrotomatidae, Deuterophlebiidae, Dryomyzidae, Ephydridae, Helcomyzidae, Heterocheilidae, Muscidae, Nymphomyiidae, Oreoleptidae, Pelecorhynchidae, Phoridae, Sarcophagidae, Scathophagidae, Sciomyzidae, Stratiomyidae, Syrphidae, Tabanidae, Tanyderidae, and Thaumaleidae) aren't included.