Dobsonflies and Hellgrammites
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40 free Dobsonflies and Hellgrammites trivia questions with answers — trivia quiz, new questions added Oct 2026.
Hellgrammites look like something a river dreamed up on a bad night: flat, armoured, fringed with filaments and armed with jaws that anglers learn to respect. They are the aquatic young of dobsonflies, big night-flying insects whose males carry tusks longer than seems sensible. This quiz gathers the best fun facts about hellgrammites and the adults they become. Expect questions on how they breathe, hunt and transform, the odd things their eggs get mistaken for, the folk names fishermen have given them, and the giant relatives that hold world records. It suits anglers, stream explorers, students of aquatic insects and anyone who has found one of these creatures on a porch screen and wondered what on earth it was.
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Q 01Hellgrammites are prized by anglers as bait for which river fish in particular?
Smallmouth bass
Smallmouth bass find the wriggling larvae hard to resist. Yet hellgrammites rarely turn up in fish stomachs, probably because they stay hidden where fish cannot reach them.
Q 02The white egg masses of the eastern dobsonfly, each about 2 cm across, are often mistaken for what?
Bird droppings
Bird droppings are what the coin-sized masses resemble once their coating dries white. Each one holds about a thousand eggs stacked in three layers.
Q 03Locals along Virginia rivers say which weather event triggers mass 'hellgrammite crawlings'?
Thunderstorms
Thunderstorms are said to set off the exodus, perhaps because the larvae feel the vibrations. Full-grown hellgrammites along a stretch of river all leave within a few days of each other.
Q 04In New Zealand, the stream-dwelling larva of the local 'dobsonfly' goes by which alarming nickname?
Toe-biter
Toe-biter is the common name for the larva, which Māori call puene. The insect is really a fishfly, the only one in New Zealand, and its young are among the country's biggest freshwater insects.
Q 05Why can't a male eastern dobsonfly give a painful bite with tusk-like jaws up to 4 cm long?
They lack leverage
They lack leverage because they are so long, so the fearsome-looking male is harmless. The female's short, stout jaws are the ones that can draw blood.
Q 06Hellgrammite is also an insect-like supervillain who debuted in 1968 in which publisher's superhero universe?
DC Comics
DC Comics introduced Hellgrammite in The Brave and the Bold, where the mutated entomologist fought Batman. He later became a recurring foe of Superman.
Q 07Adult eastern dobsonflies have fearsome jaws, but what is believed to be true of their diet in the wild?
They do not feed
They do not feed in the wild, it is generally believed, running instead on nourishment stored up as larvae. In captivity, though, they will sip honey water.
Q 08Finding hellgrammites in a stream is generally taken as a sign of what about the water?
It is clean
It is clean, or close to it: hellgrammites tend to live only in relatively unpolluted streams. That makes them handy for scientists who monitor river health.
Q 09With long, flat bodies and rows of leg-like side filaments, hellgrammites are often likened to what?
Centipedes
Centipedes are the usual comparison, but only six of those limbs are true legs. The eight pairs of side filaments work as feelers that help fend off small attackers.
Q 10After years underwater as a hellgrammite, roughly how long does a winged eastern dobsonfly live?
About a week
About a week is all the adult gets, and males may last only three days. That brief winged life is devoted entirely to mating and laying eggs.
Q 11What does Megaloptera, the Greek-derived name of the insect order that includes dobsonflies, mean?
Large wing
Large wing is the meaning, from the Greek megas and pteron. For all that wing area, the adults are weak, clumsy fliers.
Q 12The order Megaloptera holds just three groups: dobsonflies, fishflies and which smaller, dark-winged relatives?
Alderflies
Alderflies complete the trio and are the little cousins, with bodies under an inch long. Their larvae end in a single tail-like filament, which hellgrammites lack.
Q 13The old Appalachian name 'grampus' was shared by dobsonfly larvae and which giant salamander of the same streams?
Hellbender
Q 21Besides their underwater breathing organs, hellgrammites have which openings for taking in air directly?
Spiracles
Spiracles let a hellgrammite breathe out of the water as well as in it. That matters at the end of larval life, when it leaves the stream for good to pupate.
Q 22During courtship, a male eastern dobsonfly rests his long jaws across which part of the female?
Her wings
Her wings are where he lays them, at right angles, and he holds the pose until she accepts him. Older accounts wrongly claimed that males gripped the female with their jaws.
Q 23Hellgrammites, active mostly at night, catch the young of mayflies and midges using which hunting style?
Ambush
Hellbender, the largest salamander in North America, was also called a grampus in the southern Appalachians. The origin of the word hellgrammite itself is unknown.
Q 14In the dialect of the Ozarks, hellgrammites used as fishing bait go by which colourful name?
Devil scratchers
Devil scratchers is the Ozark term for the sharp-jawed larvae. An 1883 anglers' journal listed dozens of other local names, among them conniption bugs and molly-grubs.
Q 15Males of many fishflies lack a dobsonfly's giant jaws but sport which kind of antennae instead?
Feathery
Feathery, comb-like antennae are the hallmark of many male fishflies. Dobsonflies and fishflies share one family, and anglers call the aquatic larvae of both hellgrammites.
Q 16Which naturalist gave the eastern dobsonfly its first scientific name, back in 1758?
Carl Linnaeus
Carl Linnaeus described the eastern dobsonfly, still the best-known member of its genus. Most of the other Corydalus species were named more than a century later.
Q 17Where do hellgrammites spend most of their time, which helps explain why fish seldom eat them?
Under rocks
Under rocks is where they hide, usually in the swiftest stretches of a river. Collectors catch them by disturbing the stones just upstream of a net.
Q 18Nocturnal adult dobsonflies hide in streamside vegetation by day, but what strongly attracts them after dark?
Bright lights
Bright lights pull the night-flying adults in from nearby streams. Entomologists exploit the habit with black-light and mercury-vapour traps.
Q 19In which country are stream insects, dobsonfly larvae among them, sold as an edible souvenir called zazamushi?
Japan
Japan is where zazamushi are gathered, along the upper Tenryu River in Nagano. The name also covers the larvae of stoneflies and caddisflies, usually simmered or fried.
Q 20Huge, drab and fluttery, adult dobsonflies are often mistaken for which insects that never have pincer jaws?
Moths
Moths are the usual mix-up, since both are big, soft-winged and active at night. A resting dobsonfly folds its wings flat over its back, where they reach well past its abdomen.
Ambush is the method: a hellgrammite stays put and seizes whatever the current sweeps past. It ranks among the top invertebrate predators of its stream.
Q 24Lacking silk glands, a full-grown hellgrammite pupates inside which kind of shelter?
A cell dug in soil
A cell dug in soil does the job: the larva excavates it with its legs and mouthparts, then smooths the walls with its body. It may walk 15 metres from the stream to find a moist spot.
Q 25Inside the pupal skin, a male eastern dobsonfly's long jaws are packed away like which instrument?
Accordion
Accordion is the image an entomologist used in 1952 for the folded jaws. The packing explains why male and female pupae look much alike although the adults differ so sharply.
Q 26What is the type of insect development that takes a dobsonfly through egg, hellgrammite, pupa and adult called?
Complete metamorphosis
Complete metamorphosis is the term, though megalopterans have its most rudimentary form. Their young and adults differ less than in any other insect order with a pupal stage.
Q 27Unlike most insect pupae, which lie helpless, a dobsonfly pupa can do what if it is disturbed?
Bite an attacker
Bite an attacker is exactly what it can do: the pupa stays mobile and has working jaws. Its legs and wing buds hang free of the body instead of being sealed in a hard case.
Q 28Megalopterans such as dobsonflies were once classed in Neuroptera with snakeflies and which delicate insects?
Lacewings
Lacewings now keep the name Neuroptera for themselves and their kin. The three groups remain close relatives, and their nearest living cousins beyond that include the beetles.
Q 29Why do some US states regulate the sale of hellgrammites collected from streams?
They can be overharvested for bait
They can be overharvested for bait, since the larvae are laborious to collect and fetch high prices. Some anglers use hellgrammite-shaped lures instead.
Q 30The world's largest aquatic insect by wingspan, a dobsonfly spanning 21.6 cm, is native to which continent?
Asia
Asia is home to the record holder, Acanthacorydalis fruhstorferi. The biggest dobsonflies of its genus have bodies over 10 cm long, and its name honours the entomologist Hans Fruhstorfer.