The animal on the cover of Distributed Systems with Node.js is an antlion (Myrmeleontidae). Antlion species can be found all over the world but most are found in dry and sandy habitats nearer the tropics.
Once hatched, antlions spend the greater part of their lives as larvae. As larvae, they have large flat heads with relatively huge sickle-like jaws, three pairs of legs, and a large abdomen. They inject venom into their prey via deep groves in their mandibles, and are known for taking down prey much larger than themselves. Once the larvae are sufficiently grown, they create a cocoon and undergo metamorphosis. After metamorphosis is complete, the antlion emerges as an adult insect with a long, thin exoskeleton and long, narrow translucent wings. It then lives as an adult for about 25 days, although some live as long as 45 days. Because of this, adult antlions are relatively understudied, and are often misidentified as dragonflies or damselflies.
Antlion larvae are ferocious predators, and prey primarily on small arthropods such as ants. Many species build traps, digging a pit about two inches deep, in which it hides and waits for prey. It buries itself in the bottom of the pit with only the jaws projecting above the surface. The slope of the pit draws prey directly into the larva’s mouth. When creating these pits, the larvae often create designs in the sand, causing them to be known as “doodlebugs” in some parts of North America.
Although not as well studied as other species from a biological standpoint, the antlion has certainly left its mark on history, appearing in various literatures and folklore throughout the world. Many of the animals on O’Reilly covers are endangered; all of them are important to the world.
The cover illustration is by Karen Montgomery, based on a black and white engraving, original source unknown. The cover fonts are Gilroy Semibold and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag’s Ubuntu Mono.