The summit of Flagstaff Mountain is dominated by old ponderosa pines. Within the last several decades, drought, high winds, mountain pine beetles and mistletoes have taken their toll, leaving numerous stumps 2 to 4 feet tall.

As I walked past a stump, I noticed the bark was separating from the wood. Curious about who had taken up residence, I peeled a piece of bark. Fragments of paper wasps, Polistes dominulus, tumbled out. When I returned the next day to photograph overwintering paper wasps, I found only more fragments of wasps, but hundreds of flies and dozens of green lacewings.

It was a windy, cold day in early March, so the lacewings could hardly move, and only a few of the flies responded to the sudden sunlight. I took some photographs and became curious about this species of green lacewing. But when I looked at the literature, I discovered that identification from photographs was not practical.

The insects that we know of as green lacewings are in the family Chrysopidae and are probably in either the genus Chrysoperla or the genus Chrysopa. But these groups are so similar that species have been taken out of one to be put in the other, and adults in both are called common green lacewings.

Judging from the published literature, the most-studied green lacewing is Chrysoperla carnea, but recently we learned that it is not a single species. A study of morphology and songs revealed it to be a series of morphologically indistinguishable subspecies recognized by the songs that they use in courtship. Courting lacewings sing duets, and if the male and female sing different songs, courtship is terminated.

A more recent and comprehensive study examined the entire genome throughout C. carnea’s geographic range, which includes all major land areas in the Northern Hemisphere, the Indian subcontinent and Africa. This study revealed different songs marked full species — the C. carnea group contains 24 species, morphologically similar, using different songs, and frequently living in different habitats, such as grasslands, meadows, deciduous forests and coniferous forests.

When I first saw lacewing eggs on my roses, I did not recognize them as eggs but feared that some weird fungus had infected the leaves. Stiff white threads, perhaps a half-inch in length, hung from the bottom of a leaf, each dangling an elliptical, pale green egg.

When the eggs hatch, the larvae resemble larval ladybugs and have been described as miniature alligators with ice tongs for jaws. The protruding jaws are large and hollow and are used to grab, inject and drain prey. A larvae attacks prey by piercing with its mandibles, injecting venom through the mandibles and then sucking the digested innards through the mandibles. The venom is so effective that it liquifies muscles and organs in less than 90 seconds.

Lacewing larvae are the friend of gardeners, for they consume aphids, mealybugs, spider mites, leafhopper nymphs, caterpillar eggs, scales, thrips and whiteflies. Their preference for aphids has earned them the common name aphid lion.

While larvae are predatory, adults in the genus Chrysopa retain their taste for aphids but add pollen, nectar and honeydew to their diets. Lacewings in the genus Chrysoperla switch entirely to nectar, pollen and honeydew.

Ants often “farm” aphids, protecting them from predators so they can collect honeydew, excess sugars excreted by aphids. To avoid ant attacks, larval lacewings camouflage themselves by attaching hollow corpses of drained aphids to themselves. Apparently, ants are fooled by trundling piles of aphid carcasses.

Eggs are collected from farmed lacewings for sale to gardeners. To check on the ease of ordering lacewing eggs, I did a quick web search and came up with four different suppliers (in Ohio, Arizona and two in California) ready to ship the eggs.

I had similar success in a search in Europe and the U.K. One supplier listed 33 garden pests that could be managed with lacewing larvae. One company distributes Chrysoperla rufilabris eggs, but a range map for this species shows it is native to parts of eastern Canada and the U.S., and hardly penetrates the Great Plains. That company mentions that it cannot ship to Hawaii and Alaska, but apparently it will ship to all of the contiguous 48 states, including the Great Plains and Western states where C. rufilabris is not native. This is handy for gardeners, but free shipping of insect eggs here and in Europe brings to mind well-intentioned introductions resulting in horror stories of unanticipated consequences.

Adults have a tympanal organ at the base of their forewings that allows them to hear courtship songs and to be wary of predators. Lacewings are most active at night, when bats are hunting. If a lacewing detects the sound of bat sonar, it folds its wings together, making a smaller sonar target, and dives to the grasses or shrubbery for protection.

Lacewings are resourceful. They stun and liquefy their prey with venom, camouflage themselves from ants, sing duets to choose their mates, and listen for sonar to evade bats.