Periodic cicadas are found only in eastern North America. There are seven species in the genus Magicicada -- four with 13-year life cycles and three with 17-year cycles. The three 17-year species are northern in distribution, while the 13-year species are generally southern and midwestern. The periodic cicadas can be divided into three species groups (-decim, -cassini, and -decula) with slight ecological differences. Magicicada are so synchronized developmentally that they are nearly absent as adults in the 12 or 16 years between emergences. When they do emerge after their long juvenile periods, they do so in huge numbers, forming much denser aggregations than those achieved by most other cicadas.

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 can't wait for the next one!

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"Sharpshooter" is one common name for the leafhopper subfamily Cicadellinae, which includes Paraulacizes, Oncometopia, Cuerna, Draeculacephala, Graphocephala and many other genera. They get this name from their habit of feeding on the watery sap of xylem tissue, which conducts moisture from the roots up to the leaves. Excess water droplets are forced out the tip of the abdomen (Fig 1.) with an audible popping noise, hence the common name. [1]