They are large, red-eyed insects about 1 ½ inches long.  They are due to emerge from the ground after 17 years. 

They apparently have a nutty flavor.  Their shell is made of a substance called chitin, which a little may be beneficial, but too many may cause digestive upsets.

The Washington-based Humane Society is warning everyone to watch your pets.

Visit the links below to learn more information: 

http://www.rrecord.com/din1.asp

http://www.usatoday.com/news/health/2004-04-28-cicadas-pets

http://www.dcmilitary.com/army/pentagram/9_features/28959-1

http://www.medicdirect.co.uk/clinics/default.ihtml?step=4&pid=2073