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Show 52 INSECTA. FAMILY III. GALL INSECT A. In this last family( I), of which De Geer makes a particular order, there are but five joints in the tarsi(2), with a single hook at the extremity. The male is destitute of a rostrum, and has but two wings, which are laid horizontally on the body, one over the other ; the abdomen is terminated by two setre. The female is apterous and provided with a rostrum. The antennre are filiform or setaceous, and most commonly composed of eleven joints(3). They constitute the genus Coccus, Lin. The bat·k of various trees is frequently covered with a multitude of little oval or rounded bodies, in the fot·m of fixed shields or scales, in which, at the first glance, no external organs indicative of an In· sect are perceptible. These bodies are nevertheless animals of this class and belong to the genus Coccus. Some are females, and the remainder young males, the form of both being nearly similar. An epoch, however, soon arrives in which all these individuals expe· rience singular changes. They then become fixed; the male larva: for a determinate period, requisite for their ultimate metamorphosis, and the females for ever. If we observe the latter in the spring, we shall find that their body gradually increases to a great volume, and finally resembles a gall-nut, being sometimes spherical, and at others reniform or scaphoid. The skin of some is smooth and level, that of the remainder presents incisures or vestiges of segments. It is in this state that the females receive the embraces of their males, soon after which they produce a great number of eggs. They slip them between the skin of their venter, and a white down which covers the ( 1) Or the Gallinsectes of the French naturalists. .11m. Ed. (2) M. Dalman, Director of the Cabinet of Natural History of Stockholm, in a Memoir on certain species of Coccus, presumes that there are three of these joints. (3) Nine in the malea described in this Memoir. HEMIPTERA. 53 spot they occupy. Theit· body then becomes desiccated and forms a soli.d ct·ust or sh~Il which c~vers their ova. Othet· fe~ales protect the1rs by envelopmg them wtth a white substance resembling cotton. Those which are spherical form a sort of box for them with their body. The young Cocci haYe an oval body, much flattened and furnished with the same organs as that of the mothet·. They spread themselves over the leaves, and towar·ds the end of autumn approach the branches, on which they fix themselves to pass the winter. The females prepare to become mothers on the return of spring, and the males to transform themselves into chrysalides under their own skin. These chrysalides haYe their two anterior legs dit·ected forwards and not backwards like their remaining four and the whole six 1 in t.hose of the other sex. Having acquired their wings, these rna es tssue backwards ft·om the posterior extremity of their domi~ cil, and proceed immediately in search of theit· females. They are much smaller than the latter. Their copulating apparatus forms a recurved kind of tail between the two terminal setc:c of the abdomen. Re:umur saw .two granules resembling simple eyes on that part of theu· head whtch corresponds to their mouth. I have distinguished on the head of the male, C. ulmi, ten similar bodies, and two species of halteres on the thorax. Geoffroy says the females have four white t~r~ads at the posterior extremity of their abdomen, which are only nstblc by so pressing that part of the body as . to make them protrude. J?orthez has observed a species on the Euphorbium characias ~l11ch appears to differ in fot·m and habits from the others. This mduced h~s friend, the late M. Bose, to convert that species into a ?~nus wluch he named northesia. The antenna:: consist of nine JOints, those of the male being longer and more slender in the male tha~ i~ the female. The latter continues to live and run about after laymg her eggs. The posterior extremity of the male's abdomen is furnished with ~ tuft of white threads. This Insect is consequently more nearl~ alhed to the Aphides than to the Cocci( 1 ). :he Gallmsecta appear to injure trees by a superabundant sudoresls thro.ugh the punctures they make in.them, and of course those who c~ltlvate the :each, Orange, Fig and Olive are particulat·Iy on thelr guard agamst them. Certain species fix themselves to the roots of plants. Some are valuable for the rich red colour they fur- (1) M.' Carcel, a. zealous and learned entomologist, has lately confirmed these o}>~ervatlons by new investigations. Sec the Nouv. Diet. d'IIist. Nat. 2d edit article DortMa. ' ., |
