| Fig. 559.—Hylesinus piniperda. | Fig. 560.—Larva of Scolytus. |
Scolytus, Hylesinus, and Bostrichus, which are connected with the weevils, hollow out galleries between the wood and the bark of different trees, when in the larva state, and devour the leaves in the adult state. Fig. 559 represents the Hylesinus piniperda. The Scolyti are sometimes so numerous in the forests, that the trees are tattooed all over by the larvæ. In 1837, they were obliged to cut down, in the Bois de Vincennes, 20,000 feet of oak trees, aged from thirty to forty years, completely ruined by the ravages of the Scolytus, whose larva is here represented (Fig. 560). The genus Tomicus, hairy, and of a tawny colour, are a terrible plague to pine forests. In 1783, in the Forest of Hartz, 1,500,000 of trees were destroyed by these insects. Often have the priests implored, in the churches, the Divine clemency, to put an end to the devastations made by them.
We arrive at the tribe of the Longicornes, which contains beautiful insects, of elegant shape and varied colours, sometimes also of rather large dimensions.
The genus Cerambyx has the antennæ very long; they exceed in some of the species two or three times the length of the body. The larvæ are large whitish worms, which live in the wood of trees, the adult insects frequenting flowers, rotten trees, &c. In the month of June, on the Continent, one meets on the oaks with the Great Capricorne (Cerambyx heros, Fig. 561), of a dark brown, whose larva (Fig. 562) scoops out its galleries in the interior of the tree, and often occasions much damage.
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Fig. 565.—Lady-bird (Coccinella septempunctata). |
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| Fig. 563.—Larva of Lina populi. |
Fig. 564.—Larva and imago of Crioceris merdigera. |
Fig. 566.—Larva of the Lady-bird. |
The Chrysomelidæ are other phytophagous insects, dressed in the brightest colours, having short and thick-set bodies. The larvæ, soft and ovoid, devour the leaves of trees. One of the best known species is Lina populi, of a bronzed colour, with red elytra, whose larva (Fig. 563), of a greenish grey, devours the leaves of the poplar-tree. The Galerucæ and the Alticæ belong to the same family, as also do the Cassidæ, the Crioceres, and the Donaciæ. The Cassida viridis frequents nettles and artichokes; the elytra are of rounded form. Fig. 564 represents the Crioceris merdigera, a great rarity in this country. The Crioceris asparagi, or Asparagus Beetle, tawny, and barred with black, resembles it in habit.
The last tribe of Coleoptera comprises the Coccinellidæ, or Lady-birds (Fig. 565). These little globular, smooth insects, red or yellow, with black spots, are very useful to us, for they clear the trees of the aphides and other mischievous insects. Their larvæ (Fig. 566) make use of their front legs to carry their prey to their mouths. When danger threatens a Coccinella, it hides its feet under its body, and remains sticking to the stem of the bush. If you touch it, it allows itself to fall to the ground, but sometimes opens its elytra, and flies off rapidly. It also exudes from the articulations of its abdomen a yellow mucilaginous liquid, of a pungent and disagreeable odour. This is the only means of defence possessed by this little inoffensive being, which deserves in all respects the name of "Bête à bon Dieu," which the French children give it.