The ten-lined June beetle, also known as the watermelon beetle, is a scarab beetle, living in the western United States and Canada.
Like all living things in this world that are not plants, bacteria, or fungi, the ten-lined June beetle is classified as Animalia, that is, within the animal kingdom, and falling within the Arthropoda phylum, the Hexapoda subphylum and within the insecta class. They are of the coleoptera order, i.e., beetles, and the polyphga suborder, meaning water, rove, scarab, long-horned, leaf and snout beetles, and within the superfamily Scarabaeoidea, which includes scarab, stag and bess beetles, the Scarabaeidae family of scarab beetles, the Melolonthinae subfamily of May beetles and Junebugs, the Melolonthini tribe and the Polyphylla genus of lined June beetles and the decemlineata species, literally meaning ten-lined June beetle.
Polyphylla decemlineata adults are attracted to light and feed on foliage. They can make a hissing sound when touched or otherwise disturbed, which can resemble the hissing of a bat. The hissing is made by their wings pushing down, forcing the air out between their wings and back. They are known, in the larval stage, as an agricultural pest affecting a wide range of crops, as the larvae feed on plant roots and can weaken or kill plants.
They are relatively large in size, some growing to 1.5 inches in length or more. As in other members of this genus, the males have large distinctive antennae consisting of several lamellate plates, which they close up when threatened. The antennae are used to detect pheromones emitted by females. The wing covers (elytra) have four long white stripes and one short stripe each. The underside of the thorax is covered with brownish hairs.
Eggs laid by females are oval, dull, and creamy. They are about 1/16 of an inch long. The larva or grub can grow up to 2 inches with 3 pairs of legs, with a white body and brown head. The larval stage can last as long as 4 years.
The ten-lined June beetle is very common throughout the Pacific Northwest as a root feeding white grub which feeds on roots of crops, garden, and ornamental plants. They are less common south of that region, but are indeed present in all of California. The beetles emerge in the summer, usually in late June through July. Attracted to lights at night and found under the lights in the daylight, they hiss and squeal when handled. They prefer sandy soil.
Ten-lined beetles take two years to mature. Upon hatching from eggs, they spend the next 24 months underground, eating roots and developing into adults, which emerge from May to June in most cases but as late as September, hence the name June beetle.
From Wikipedia http://entomology.wsu.edu