398 THE INSECT WORLD. 



found in the ashes acted upon by the nitric acid the least trace of 

 lead. This experiment proves that these insects had for their object 

 only to escape from the galleries in which they were accidentally de- 

 posited in their larva state, and that it was not until they had under- 

 gone their complete transformation that they endeavoured to gain 

 their liberty. Observations of the same kind were multiplied after 

 the Report of M. Dumeril. The Academic des Sciences received, in 

 the month of June, 1861, two Memoirs one from M. Heriot, 

 captain of artillery, the other from M. Bouteille, curator of the 

 Museum of 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 

 Acade'mie 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 Academic 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 Tenthredinet& 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 larvae 



