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Thursday, April 30, 2009

Grasshoppers


(Family Acridiidae.)The insects of this family are everywhere abundant both in number of species and individuals. They comprise some of the most destructive insects known and the migratory species have devastated the crops of many countries, more especially Russia, portions of South Europe, Algeria, India, Cape Colony, the Argentine Republic and in former years some of the western United States. In the insects of this family the antennae are short, much shorter than the body, the ovipositor of the female is short and composed of four separate plates and the tarsi are three-jointed. The hind legs are the longest and usually have stout femora, especially near the base. Among the most abundant and injurious species occurring in the U.S. are the western grasshopper or migratory locust (Melanoplus spretus), an insect which damaged western agriculture, especially in the States of Kansas, Colorado, Nebraska and Missouri; the common red-legged locust (Melanoplus femur-rubrum), a species closely resembling the foregoing but having shorter wings; the two-striped locust (Melanoplus bivittatus), a widespread form which is abundant almost every year; the Carolina locust (Dissosleira carolina), the common light-brown species seen so frequently along dusty roads ; the American locust (Schistocerca americana), more abundant in our Southern States where it occasionally becomes very injurious ; and the differential locust (Melanoplus differentialis), a species which has recently done great damage to cotton plantations in Mississippi. The lubber grasshopper of Florida and Georgia is known as Dictyophorus reticulatus. It varies in color from green to black and has very short wings. It occurs frequently in enormous numbers in the rice-field: near the mouth of the Savannah River, and is an extremely disagreeable object on which to step ; in fact, it reminds one of Thackeray's famous remark when he swallowed his first saddle-rock oyster. The corresponding lubber grasshopper of the Southwest is (Brachystola magna), and is a large greenish species.With the short-horned grasshoppers we come to the first of the Orthoptera which are musical. Almost everyone who walks in the fields knows the rattling or crackling sound produced by certain grasshoppers in their flight. It appears to be under the control of the insect. It can produce it or not, just as it pleases. Some give distinct snapping sounds, or separate, loud snaps. Still other grasshoppers play upon their instruments not during flight but while at rest. Professor A.P. Morse tells how he watched some of them (Circotettix verruculatus) on Mt. Washington sunning themselves, occasionally elevating the hinder part of the body and rapidly moving the hind thighs up and down against the wing covers, "producing a distinct 'scritching' sound clearly audible at a distance of three or four feet. This act was repeated several times at intervals of a few seconds."Life History of a Grasshopper(Melanoplus atlantis Riley.)This insect, which is known as the lesser migratory locust, is a close relative of the common red-legged locust and the western grasshopper. It occurs commonly throughout the northern United States and has for many years made occasional injurious outbreaks in a restricted region in New Hampshire where local conditions seem to favor its undue increase. The eggs are laid beneath the surface of the ground in an egg pod shape something like a bent flask, the eggs in each pod averaging from twenty-four to thirty-six in number. Each female in the course of her life usually deposits two of these egg pods although three and even four have been laid by the same female. The insect passes the winter in the egg state and the young locust or grasshopper hatches in the spring. The period between hatching and maturity averages eighty to ninety days and the grasshopper passes through four to five molts, the young grasshoppers attaining their full wings only after the last molt. In about one week after reaching full growth the insects pair and soon commence ovipositing. There is but one annual generation in New England, but two in Missouri. Egg-laying commences late in July and some of the earlier eggs may hatch in the autumn in New England, showing a tendency towards a second generation.

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