Natural History of Grenoble--containing many new observations on the perforation by insects of leaden balls contained in cartridges prepared for war. M. Milne-Edwards read to the Académie des Sciences a short Report on these works. The insect which had produced the perforations observed in the balls sent to the Crimea in 1857, and which M. Dumeril particularly studied, was the _Sirex juvencus_, and had been taken from France in the wood forming the boxes which contained the cartridges. In the other case of which we are speaking, that is to say, of the cartridges which were sent in 1861 to the Académie by Captain Heriot and by M. Bouteille, the perforations had been produced by other species. M. Milne-Edwards, who found the insect that had caused this strange damage, had no trouble in recognising it as the _Sirex gigas_, which, in its larva state, lives in the interior of old trees or pieces of wood, and which, after it has gone through all its metamorphoses, comes out of its retreat to reproduce its kind. To clear themselves a passage, they cut away with their mandibles the ligneous substances or other hard bodies they meet with on their road. It was in pursuing this object that the insects, imprisoned accidentally in the packets of cartridges when they were yet only in the larva state, must have attacked the leaden balls, as also the paper and the other matters which they met with on their road, and which opposed their passage. M. Bouteille proves, in his Memoir, that M. Dumeril has committed an error in saying that the perforating organ employed by the _Sirex_ to attack the leaden balls in the cartridges in the Crimea was the auger situated at the extremity of the abdomen of the female, and intended for cutting into that part of the wood where it is to lay its eggs. M. Bouteille has established, in fact, that they were not only the females which attacked the cartridges, but that the males, which have no auger, had occasioned the same damage. The _Tenthredinetæ_ are called "Saw-Flies," because the females are furnished with a double auger, notched like a saw, with which they cut into the branches in which they lay their eggs. The larvæ of these insects have a striking resemblance to the caterpillars of Lepidoptera. They can only be distinguished from them by a great globular head, not hollowed out, and by their abdominal legs, in general to the number of more than ten. They are called false caterpillars (Fig. 379). Most of them, when touched, erect themselves and move about in a threatening manner. They spin a silken cocoon before changing into pupæ. The _Lophyrus pini_, which devours the leaves of pine trees, belongs to this family. [Illustration: Fig. 379.--Larva of a Saw-Fly. (_Tenthredo_).] [Illustration: Fig. 380.--Lophyrus pini.] VII. THYSANOPTERA.