Insects in the order Hemiptera were historically placed into two orders, Homoptera and Heteroptera/Hemiptera, based on the differences in wing structure and the position of the rostrum. These two orders were then combined into the single order Hemiptera by many authorities, with Homoptera and Heteroptera classified as suborders.

The order is presently more usually divided into four or more suborders, after it was established that the families grouped together as "Homoptera" are not as closely related as had previously been thought. Auchenorrhyncha contains the cicadas, leafhoppers,treehoppers, planthoppers, and froghoppers. The 12,500 species in the suborder Sternorrhyncha are aphids, whiteflies and scale insects.

The suborder Coleorrhyncha (comprising the single family Peloridiidae), contains fewer than 30 species of Gondwana-distributed bugs, and is sometimes grouped with the Heteroptera (to form the suborder Prosorrhyncha). Heteroptera itself is a group of 25,000 species of relatively large bugs, including the shield bugs, seed bugs, assassin bugs, flower bugs and the water bugs.

Treehopper Ceresa taurina

The emergence of brood XIII in 2007 was quite an event here, near Chicago. There were places where the cicadas emerged by the millions and fouled roadways, sidewalks and car windshields, yet other areas just a mile away were devoid of the insects. The picture above was taken at the Morton Arboretum at Lisle, Illinois - a hotbed of the emergence. They we there by the hundreds of thousands and the roar was loud, strident, and unceasing. I hope I live until the next one!

Aphids are small, soft-bodied insects with long, slender mouth parts that they use to pierce stems, leaves, and other tender plant parts and suck out plant fluids. Almost every plant has one or more aphid species that occasionally feeds on it.

Aphids may be green, yellow, brown, red, or black depending on the species and the plants they feed on. A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface. All are small, pear-shaped insects with long legs and antennae. Most species have a pair of tubelike structures called cornicles projecting backwards out of the hind end of their bodies. The presence of cornicles distinguishes aphids from all other insects.

Generally adult aphids are wingless, but most species also occur in winged forms, especially when populations are high or during spring and fall. The ability to produce winged individuals provides the pest with a way to disperse to other plants when the quality of the food source deteriorates.

Although they may be found singly, aphids often feed in dense groups on leaves or stems. Unlike leafhoppers, plant bugs, and certain other insects that might be confused with them, most aphids do not move rapidly when disturbed. [2]