for J U L Y Ten-lined June Beetle PROPER NAME: Order Coleoptera, Family Scarabaeidae, Polyphylla decimlineata. WHEN MOST PREVALENT: June in the southern part of its range; July in the northern part of its range. SIZE RANGE: 25-35 mm in length. [View magnified Insect] WARNINGS: These insects are harmless. GEOGRAPHIC LOCATION: Southwestern United States north to the Rocky Mountain states and provinces (Canada). SOUNDS: June beetles will make a hissing sound if disturbed. Larvae live in the soil feeding on the roots of woody plants. Adults feed on the foliage of trees and bushes. They are active mainly at night, and will fly to lights in large numbers. Eggs are laid in the soil near host plants in the late spring. Larvae hatch and feed throughout the summer on the roots of the host plants. In fall, they burrow deeper in the soil and remain inactive until the following spring when they move towards the surface and resume feeding. Pupation takes place just beneath the surface of the soil, and in late June or early July adults emerge, often en masse. Adults live only a few days to a few weeks, dying shortly after mating (males) or egg-laying (females). People are often frightened by the hissing sound the June beetle makes when it is disturbed. It sounds like the insect is releasing some sort of poison gas or some other nasty toxin! But the beetle is actually making this sound by forcing air out of tiny holes, known as spiracles, which are located on the sides of its abdomen. Quite harmless! FAMILY RELATIONS a) Order Coleoptera, Family Scarabaeidae, Polyphylla crinita - the lined June beetle. b) Close cousins: Order Coleoptera, Family Scarabaeidae, Genus Onthophagus - dung beetles. [TO TOP] [HOME]