Insectoid refers to any individual, race or species of creature that possess physical characteristics common to that of an insect. These may include a chitinous carapace, compound eyes, antennae, a jointed thorax, jointed legs, a mandible, etc. There are several alien races found in science fiction which are regarded as insectoid such as the Than-Thre-Kull from Andromeda, the Sleestaks from Land of the Lost, the Ovions from the original Battlestar Galactica and the Xindi from Star Trek: Enterprise.
An interstellar race known as the Nebulons bore physical characteristics similar to cockroaches. They hailed from an unnamed planet in the M Space Hunter Nebula and came to Earth where they briefly assumed human forms. A group of humans exposed their plans, and the Nebulons revealed their true selves to them before dying in an explosion. (Godzilla vs. Gigan)
A giant terrestrial monster known as Antlar emerged in the Middle East city of Baradhi. The creature stood on two legs, had small pincers atop its head, and two large pincer claws for hands. It had a segmented plated exoskeleton, which covered its arms, legs, head and thorax. (Ultraman: The Blue Stone of Baradhi)
A race of Beetle-Men once came to Earth aboard a meteor and grew to prodigious size (though still smaller than a human). They attempted to conquer the planet by blowing up nuclear stockpiles, but the Tiny Titan known as the Atom managed to defeat them. (Atom: Invasion of the Beetle Men)
In the Star Wars mythos, there is a race of alien called Geonosians, who are semi-insectoid. They have a thick carapace exoskeleton and insectoid wings that afford them limited flight.