The Illustrated Insectopedia - Hugh Raffles (2010)



It was August 1877, and Baron Carl Robert Osten-Sacken, a Russian aristocrat recently retired as the czar’s consul general in New York, had stopped for a few days at Gurnigel, “the well-known watering-place near Bern.”1

The baron was forty-nine years old and at a turning point in his life. He would spend a year traveling in Europe before arriving in Cambridge, Massachusetts, where, once more in the New World but freed from imperial service, he would settle at Harvard’s famous Museum of Comparative Zoology, and spend the rest of his days pursuing his passion for flies. Some thirty years later, his obituarist would describe him as “the beau ideal of a scientific entomologist,” citing his mastery of relevant languages, his independence of means, his elevated social rank, his prodigious memory, exceptional observation skills, “almost perfect” library of works on the Diptera, and naturally, his impeccable manners.2

Strolling one morning in the Alpine woods behind his hotel, the baron’s eye was caught by something quite new to him, something he suspected was “unique in entomology.” It was not yet ten o’clock, but the sun was already high in the sky. Above his head, zigzagging among the shafts of light slicing through the shadows of the fir trees, were swarms of tiny flies. “What attracted my attention,” he wrote that October in an enthusiastic note from Frankfurt, was “the uncommonly brilliant white or silvery reflection which they gave in crossing the sunbeam.”

The baron gave chase with his net, caught one with his forceps, and was “astonished to find a much smaller fly than I had expected, and without anything silvery about it.” The insect he held was dull gray and thoroughly unremarkable looking.

Tiny things can be slow to reveal their secrets. But Baron Osten-Sacken’s exceptional observation skills yielded a clue: “I perceived on the gauze of my forceps, not far from the fly, a flake of opaque, white film-like substance, oval, about 2 mm. long, and so light, that the faintest breath of air could lift it.” He thinks of the fine silk spun by ballooning spiders preparing for takeoff. “But for its much lesser weight, it might also be compared to the petal of a small white flower.” He catches another, then another, and each time pulls from his net a male fly clutching under its body the same diaphanous structure. He concludes that “these bits of white tissue, which they waved like flags behind them,” are the source of the brilliant reflection. But he has no idea what they are or why the flies carry them.


The baron was the first entomologist to encounter balloon flies, as these insects came to be known. But he was by no means the last. In the decades following his discovery, more and more of these animals were described. All turned out to be male. All carried an object of some kind. And all of them belonged to the Empididae, the so-called dance flies, famous for their huge flittering swarms.

In 1955, Edward Kessel, associate curator of insects at the California Academy of Sciences, wrote a definitive paper on the balloon empidids in which he suggested that the baron and his successors had been unlucky enough to have stumbled upon a limit case.3 It was as if, knowing only European painting of the late nineteenth century, these gentlemen entomologists had wandered into the art museum and met a wall of Mark Rothkos. They had come upon an abstraction, an inscrutable object that betrayed no trace of the original from which it was distilled. Really, encountered like this, these flakes of white tissue could have been anything, anything at all, even the “aeronautical surfboards” proposed by Josef Mik in 1888.

But over time, Kessel wrote, observers noticed that the male balloon fly always presented his substance to a female fly and, soon after, the two of them had sex. Rather coyly, entomologists called these objects “nuptial gifts,” a euphemism still widely used today. Some of the gifts consisted simply of an unadorned dead insect, in others the corpse was bound in frothy or silky tissue (sometimes casually, sometimes carefully), and in some there was no body at all, the elaborate wrapping itself being the offering.

Kessel created an evolutionary history of the empidid gift. He described a hierarchy of species defined by their gift-giving habits, from the primitive to the urbane, the crude to the refined. It was an eight-stage history in which the object in question evolved from something obvious in the most material way (food) to something subtle, recondite, and arguably immaterial (a symbol).4

Empidids are predatory carnivores, and much as it is for praying mantises and many spiders, their sex life is a fraught affair. The way Kessel tells it, the males have become calculating cynics, the females capricious and, as luck would have it, easily distracted. His males—no surprise here—do just about anything for sex; his females, material girls all the way, do whatever it takes to get the bauble. It’s very mid-1950s, very Gentlemen Prefer Blondes, very film noir too, except that instead of taking place in a nightclub, this is all happening in what biologists call a lek, an arena where the males perform for attention and the females get to pick from the assembled “eligible bachelors.”

The stakes are high. Kessel’s males are cocky and cunning, but edgy and anxious too. They’re calibrating for optimum mileage, making sure their temptations cost as little as possible but still do the job. They’re really good dancers. They’re constantly watching their backs. Kessel was right that Osten-Sacken could never have figured this out.

Kessel found species of empidids for each of his eight evolutionary stages. From the most primitive, in which “the male does not bear a wedding gift for his bride,” to a second stage, in which he carries “a wedding present in the form of a juicy insect,” to a third, in which “the prey has become the stimulus for mating,” to a fourth, in which “the prey is more or less entangled in silky threads.”

Kessel and his wife, Berta, found the fifth stage in Marin County, north of San Francisco, and named it Empis bullifera for the sticky bubbles it uses to make its container. They spent the summer of 1949 observing mating pairs “drifting in lazy flight, first in one direction and then in another, back and forth within the clearing under the trees, their glistening white balloons producing flashes whenever they penetrate a sunbeam.” They watched the animals meet in the air, watched them embrace, and watched the males present the females with balloons containing a midge, a spider, or a tiny psocid. Then they wrote an article together announcing the new species, which they published in 1951 in the Wasmann Journal of Biology.

In the sixth and seventh stages, the male has sucked the prey dry before giving it to his partner. All she receives is an inedible husk. Nonetheless, the familiar sequence unfolds: the flies embrace, the balloon changes hands (well, legs actually), and sex ensues. The eighth, and final, stage was the one witnessed by the baron. Among Hilara sartor and a few other species, the enigmatic gift contains no prey at all, not even the withered shell.

Kessel emphasized distinctions among species. So do contemporary biologists, but they also recognize a good deal of within-species variation. They describe dance fly species in which males offer both large and small presents and others in which they offer both edible and inedible ones. They also describe males whose prey gifts are hunted from their own species and others who eschew insect prey altogether to gather entirely different gifts—flower petals, for example. Despite this variety of behavior, the small number of researchers who study these little flies still closely follow Kessel’s account of an evolutionary Diptera economicus, in which males do everything they can to minimize their energy output and maximize their reproductive return, relentlessly downgrading their gifts in the effort to get cheaper and cheaper sex.

This substitution of “empty gifts” for nutritious ones has become a famous case of “male cheating,” an idea that doesn’t require just the males’ shrewd duplicity but also relies on the females’ slowness.5 Even when the gifts are “worthless,” even when they’re just the cheapest gimcracks—plain cotton balls provided by biologists, for example—the researchers describe the foolish female fly giving the fake-gift giver what he wants, or at least the researchers see the female taking so long to catch on to the phoniness of her reward that she’s given her partner what he wants before she realizes she’s had nothing in return. Tricked. Deceived. Fucked. Over and over and over.

Or so the story goes.


Writing about Ellis Island, the French novelist Georges Perec found himself haunted by what might have been, by what he called “potential memory.”

“It concerns me, it fascinates me,” he wrote, “it involves me, it questions me.” Broken by the deportation of his mother from Paris to Auschwitz when he was six years old, Perec kept running into histories that could have been his own, a boy who veers down a monochrome side street half a block ahead, “a life-story that might have been mine,” “a probable autobiobiography,” “a memory that might have belonged to me,” books full of absences, a novel without the letter e, a novella that lacks the other vowels: a, i, o, and u.6

These fictive histories aren’t just imaginative games. They’re hard facts of existence that weigh down the present with paths not taken. We all have them: the discarded negatives of decisions whose weight only later becomes clear, the psychic resonances that complete the life we do have, the life that does get made. When Sharon shivers without warning, she says, “Someone just walked over my grave.”

Kessel saw that Osten-Sacken’s flies flittered not only in the open forest but also in a narrative vacuum. How could the baron and those who followed him take these inscrutable flakes—like petals but so much less substantial—and build a story when there was no history? What could they do when none of the signs signified, when all they had was gossamer? The beauty touched them. But that just made it worse. Without even potential histories, how could they understand what might be, what might have been, and what now was?

But the opposite problem is equally real. The problem of too much history. How can one understand what might be, what might have been, and what now is when confronted by a history so potent that it makes different or simply more expansive stories so hard to imagine?

Of course, it is possible that male empidids are cheats and that female empidids are dopes. But it’s also possible that male and female dance flies are not constantly at war with each other and are not always caught up in relationships drawn straight out of daytime soaps.

“Perhaps animals do lie to each other now and then,” writes the evolutionary biologist Joan Roughgarden, “but biologists have yet to catch them in a lie.”7 She presumes that animals are honest until proven devious and that they have capacity until proven incapable. What if, like her, we assume that those female flies know what they are doing? What if those empty balloons actually are gifts—but gifts whose value we don’t understand? Perhaps these tiny structures possess an ecstatic tactility. Perhaps they’re seductively comforting. Perhaps they trigger memories or appetites. Perhaps they’re symbolically precious, full of affect and meaning. Perhaps the flies just like them.

How do we avoid turning the empidids into one of Stephen Jay Gould’s evolutionary just-so stories, stories that can’t be validated or falsified because they begin from the conviction of a mechanism—in this case, sexual selection driven by sexual conflict—and shoehorn whatever data emerge from experiment into a preexisting argument? What, for instance, if we leave open the possibility that there is a diversity of relationships among these flies that corresponds to the diversity of behaviors that biologists have already observed? What if we assume that the willingness of many female flies to accept cotton balls indicates that rather than being “worthless,” the objects have qualities unknown to us? Is it too obvious to point out (again) the hazards of presuming what an object is and what it does for beings whose ways of being are so different from our own?


It is August 1877, and Carl Robert Osten-Sacken stands among the trees behind his hotel in Gurnigel, shading his eyes as he gazes up into the dappled sunlight and marvels at the dazzling flashes of Hilara sartordancing in and out of the sunbeams.

It is summer 1949, and Edward and Berta Kessel keep impossibly still in Marin County, California, so as not to disturb the mating Empis bullifera and especially not the female exploring her delicately wrapped present.

It is May 2004, and on a farm in Fife, Scotland, Natasha LeBas uses her forceps to prize a dead insect from the clutch of a female Rhamphomyia sulcata and, hoping against hope not to interrupt the flies’ coitus, carefully swaps the prey for a cotton ball.

It is mid-2010 or further into the future, and here we are again, caught between the unavoidability of comparison and the awareness of fundamental difference. Here we are still, caught in that imperative to understand, bearing our various tools for analysis and interpretation, trying to locate both the objective principles and the lived life in the enigmatic clues of observed behavior. Here we are again, caught somewhere between the reduction that makes things fathomable and the generosity that gives them fullness. Here we are, caught looking yet again, still looking, this time at tiny flies and their shiny gifts.