Ten-Lined June Beetle

Polyphylla decemlineata

Last updated: October 4, 2022
Verified by: AZ Animals Staff
© GypsyPictureShow/Shutterstock.com

These beetles can take up to two years to complete one generation. In fact, larvae can develop in soil for up to 4 years!


Ten-Lined June Beetle Scientific Classification

Scientific Name
Polyphylla decemlineata

Read our Complete Guide to Classification of Animals.

Ten-Lined June Beetle Conservation Status

Ten-Lined June Beetle Locations

Ten-Lined June Beetle Locations

Ten-Lined June Beetle Facts

Name Of Young
Grub or Larvae
Group Behavior
  • Solitary
Fun Fact
These beetles can take up to two years to complete one generation. In fact, larvae can develop in soil for up to 4 years!
Other Name(s)
Watermelon beetles
Forests, shrublands, and farmlands
  • Nocturnal
Favorite Food
Common Name
Ten-lined June beetle
North America
USA and Canada
Nesting Location

Ten-Lined June Beetle Physical Characteristics

  • Brown
  • Red
  • Black
Skin Type
Larvae live for 2 to 4 years
0.8 to 1.5 inches

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View all of the Ten-Lined June Beetle images!

Ten-lined June beetles are members of the Scarabaeidae family and fall into the class Insecta. They occur all over the globe and are known for their unique wings, which are covered in linear patterns.

They also go by the name watermelon beetles and have very poor eyesight, which is why they are so attracted to lights. Unfortunately, their fascination for lights is their downfall because it makes them easier to catch in backlight cages and other gadgets.

Ten-lined June beetles are native to the Northern Hemisphere, with dense populations in the United States and Canada.

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Their primary diet consists of tree roots; however, they also like to drink grapefruit and raspberry juice. These beetles are known as pests because they can cause the trees they feed on to decay. While the larvae can live for around 4 years, adults barely survive for more than 10 months.

Ten-Lined June Beetle Species, Types, and Scientific Name

The ten-lined June beetle’s scientific name is Polyphylla decemlineata, and the genus consists of 85 species, which include:

Saline Valley Snow-front Scarab

The saline valley snow-front scarab (Polyphylla anteronivea) is also known as the saline valley snow-front June beetle, and they belong to the family Scarabaeidae.

This species is native to North America. Their ideal habitat is forests or orchards, and they are distinguished by their white elytra scales that form stripes down their bodies. Unfortunately, adults are drawn to lights, which often leads to death.

Saline valley snow-front scarabs lay their eggs in the soil, usually close to plants where the larvae hatch and bore down into the roots, where they will live and feed for two to three years before morphing into pupae.

Spotted Warner Valley  June Beetle

Spotted Warner valley June beetles primarily occur in the Northern Hemisphere and mainly emerge during warm spring evenings; they, too, are attracted to lights. They vary in size from 0.5 to 1 inch, and have metallic wings (elytra) that cover most of their bodies.

These beetles are nocturnal and feed on flowers and foliage, often causing extensive damage. Their larvae are called white grubs and measure around an inch in length, burrowing into the soil where they stay for years.

In addition to damaging flowers, they also destroy:

  • Corn fields
  • Small grains
  • Potatoes
  • Strawberries
  • Lawns
  • Pastures

Mount Hermon June Beetle

The Mount Hermon June beetle originated in Santa Cruz County, California, where it was first discovered in 1938. The males are petite with black heads and dark brown elytra, which are covered in long brown hair. In addition, they have stripes all over their bodies. These stripes are broken and usually resemble discontinuous clumps.

The females are more prominent and also have black heads; however, the lower part of their faces are chestnut in color. In addition, their head, thorax, and legs are covered in golden hair. The difference in size between this species’ sexes is quite significant, with females measuring 0.87 by 0.43 inches and males 0.79 by 0.39 inches.


Ten-lined June beetles belong to the order Coleoptera and are best distinguished by their front pair of wings called elytra. This order is the largest of the Insecta class and contains around 400,000 species, with new specimens discovered often.


They are members of the family Scarabaeidae, who are recognized for their stout bodies and metallic colors. Members vary in size and can measure between 0.059 to 6.2 inches.

One of their distinguishing features is their clubbed antennae that compress into a ball or fawn out like leaves, which they use to sense odors.

In addition, many species in this family are burrowers, and have legs adapted for digging. Some adult species have horns on their head, which they use to fight over resources or mates. The largest species ever found was fossilized, named Oryctoantiquus borealis, and it measured 2 inches long.

Appearance: How To Identify the Ten-Lined June Beetle

The ten-lined June beetle is best recognized by the four white lines running down its elytra. In addition, they have antennas with lamellate plates. Their coloring differs depending on the sex, but they are generally black or reddish-brown in color.

These beetles are usually between 0.8 to 1.5 inches long. However, the grubs can reach lengths of 2 inches if they receive proper nutrition. When compared to the Hercules beetle, they are nearly half the size!

Habitat: Where to Find the Ten-Lined June Beetle

These beetles occur throughout the Northern and Western United States and Canada. However, large populations inhabit states like:

  • Kansas
  • Arizona
  • California
  • Nebraska
  • Nevada
  • Colorado

They prefer to live in forests, shrublands, and farmlands and are considered agricultural pests because tin-lined June beetles’ larvae live in the soil and feed on the roots of plants, destroying them in the process.

Diet: What Do Ten-Lined June Beetles Eat?

The diet of ten-lined June beetles varies, but they primarily feed on plant-based food like

  • Leaves
  • Walnut trees
  • Oak trees
  • Plant roots

The grubs are detrimental to plants because they cause decay when feeding on the roots.

Life Cycle of the Ten-Lined June Beetle

The life cycle of ten-lined June beetles is relatively long for an insect. These beetles can take up to two years to complete one generation. In fact, larvae can develop in soil for up to 4 years!

The larvae inhabit the top soil (around 14 inches from the surface), where they feed on roots. Adult females will make their way to the surface every summer or early autumn and release pheromones to attract males.

Around this time, males will fly around from dusk until midnight in search of a mate. Once the mating is over, the females burrow back into the soil to lay their eggs.

While the larvae can live up to four years, there is no record of the lifespans of adults; however, it is thought that they die after laying eggs.

Prevention: How to Get Rid of the Ten-Lined June Beetle

Unfortunately, the only way to exterminate heavily infested areas is by removing the trees, and the surrounding soil needs to be fumigated to prevent the larvae from claiming nearby trees.

In addition, commercial growers apply soil insecticides to kill the larvae as aboveground chemicals do not work.

However, these methods only apply to large areas like forests. Home gardens are a different story. Female ten-lined beetles cannot fly, so populations spread slowly, making them easily manageable in a small space.

Homeowners can use lights to attract these beetles and capture them with a net. Some people feed them to their chickens, while others squish them once caught.

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About the Author

I am a 33-year-old creative and professional writer from South Africa. Wildlife is one of my greatest passions and led me to become the writer I am today. I was very blessed to work with an abundance of wildlife (mainly big cats) and captured my unique experiences in writing. But I wanted to take it further, and I ventured into the freelancing world. Now, I get to spend my days writing about animals; what could be better?

Ten-Lined June Beetle FAQs (Frequently Asked Questions) 

How big is a ten-lined June beetle?

These beetles are usually between 0.8 to 1.5 inches long. However, the grubs can reach lengths of 2 inches if they receive proper nutrition.

What happens if a June bug lands on you?

There is a superstition that when a June bug lands on you, it could be a sign to work on your own outer shell and to start protecting yourself from those around you who wish to bring you harm.

What is the difference between a June bug and a beetle?

There is no difference, they are merely two separate names for the same insect.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.

  1. The Daily Garden, Available here: https://www.thedailygarden.us/garden-word-of-the-day/ten-lined-june-beetles
  2. Encyclopedia (1970) encyclopedia.com/environment/science-magazines/mount-hermon-june-beetle
  3. Wikipedia, Available here: https://en.wikipedia.org/wiki/Ten-lined_June_beetle
  4. Kidadl, Available here: https://kidadl.com/facts/animals/ten-lined-june-beetle-facts

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