CICADA. One of the Cicadithe. a family of homopterous bugs, composed. for the most part, of large insects, very few measuring less than one inch across the opened wings, While many are as large as seven inches. The fore wings are usually transparent, but in some forms are highly pigmented, especially With black and yel low. About 800 speeies are known, mostly trop ical.
Habits, cte.—The life of an adult cicada is noisy and short. These are, indeed, the noisiest insects in the world. Uarcin heard them while on the Beagle, when it was anchored a quarter of a mile from shore. Gnly the males give the note. "Ilappy," said the Greek poet Nenarchus, "the cicadas' lives, for they have voiceless wives." As no special auditory organs have been detected, it has been suggested that cicadas are capable of feeling rhythmical vibrations only. The sound making organs which the males possess fully developed, and the females only partly, are pecu liar to the cicadas. They consist of enlarge ments of the metathoraeie epimeras in the form of an opercular covering beneath which there is a very complicated apparatus. The sound is made by the rapid vibration of one of the mem branes called the timbal. The other two mem branes probably are set in vibration by the first, and, in connection with the opercula. the three stigmata and the whole skeleton of the insect, in tensify the sound. The females are provided with powerful ovipositors. The eggs are de posited in the twigs of trees or shrubs or in the stems of herbs. The young hatch out in a few weeks. drop to the ground. and begin there a long subterranean existence. They feed on the sap trom the roots of trees. The larvae may pene trate as deep as twenty feet below the surface of the gumnd, where it is difficult to make out their life-history. The manner of transformation from the larva to the pupa we do not know. The pupa is incased in a hard shell and when about ready to emerge front the ground may construct a eliininey of earth several inches in height, but whether this is it purposeful act or not we do not know. When the pupa crawls•• out of the ground it fastens itself to some firm object, such as a wooden fence or a tree-trunk, the skin splits along the dorsal line of the thorax, and through this the adult winged insect 'merges. The pupal
skin when dried still retains the shape of the pupa, and may be found attached to the sup port several days after the adult has flown away.
In the United states the two commonest, forms are the dogday harvest-fly (cicada tibieens) and the periodical cicada or 13 to 17 year locust (ni•iold scii/endecira). The harvest-fly is the black-and-green one that appears every year in midsunimer, and gives out its prolonged. shrill. and to many persons nerve-racking, cry front tree-tops during the heated hours of the day: this form matures in two years, but since there are two different broods, one appears every year.
The Periodical Cirada.—This species requires from 13 to 17 years for devi•opment, mainly, to the temperature of the locality in which it breed•. heat hastens its development, hence the 13-year forms occur in the South, but in each locality there arc always some individu als that come not a year or two ahead of the main brood and others that lag a few years be hind. This form has the greatest longevity of any known insect. The time of its periodicity has Le•n made out by noting its appearance in certain localities for a considerable number of years, twenty•two brood, having thus been de termined. Several of these broods, which are dimorphic. may coexist in the same locality. Hence larvae of different ages, of several genera tions.. may be in the ground at one and the same time and they will appear as adults in dif ferent years. The sound made by these insects is peculiar, very loud, and closely resembles the humming of a resonant telegraph pole when its wires are vibrating in a strong breeze.
Consult: Woodworth, "Synopsis North Amri can Cicadidie," in Psyche, Vol. V. (('ambridge, 1SSS). For the 'seventeen-year See Peri...Heal ('icada," an illustrated mono graph of 14S pages, by C. L. 3larlatt, Bulle tin 14 of the United States Dcpartal, at of culture (Washington, IS9S). See LocusT.