In those days, therefore, concealment was rather ridiculed than praised, the power of the new arm not being as yet appreciated. I well recollect, in the earliest days of the Volunteer movement, hearing a Volunteer captain declare, amid the cheers of his company, that “he had never sneaked behind a tree in all his life, and was not going to begin now.” In the present day, the power of the missile has been developed with such astounding rapidity, that to be exposed to the fire of rifles or cannon is almost certain death. Indeed, the only safety of the defence lay in the fact that the smoke soon rendered very accurate shooting impossible at long ranges, and that at short ranges, if a man got a bullet through his body, it mattered little to him whether the missile were a spherical musket-ball or a conical rifle-bullet. [Illustration: REDUVIUS (MAGNIFIED).] [Illustration: CUCKOO-SPIT.] [Illustration: SPIDER-CRAB.] [Illustration: MASKING GUNS.] [Illustration: BIRNAM WOOD.] Just, then, as forts have latterly sunk into the earth for the purpose of strength, so have our modern soldiers found that the true principle of modern warfare is never to lose sight of the enemy, and never to allow the enemy to see yourself or the disposal of your troops. Everything must be revealed to the commander-in-chief, everything must be concealed from the enemy. In the late Franco-German war the principle of concealment was largely used, and when cannon were brought into the field by the Germans for the purpose of attacking fortresses, they were always hidden under branches of trees, so that the enemy should not distinguish them from the ordinary features of the country, and that the sparkle of the sunbeams upon them might not be seen. It would be almost superfluous to remind the reader of Malcolm’s stratagem when besieging Dunsinane Castle:-- “Let every soldier hew him down a bough, And bear’t before him; thereby shall we shadow The numbers of our host, and make discovery Err in report of us.” Precisely similar modes of concealment are to be found in the animal world. There is a certain insect belonging to the Heteroptera, and scientifically named _Reduvius personatus_. I am not aware whether it has any popular name. It is insectivorous, and ought to be welcomed in houses, as it is particularly fond of the too common bed-bug. So carnivorous are these insects that one of the Reduviidæ killed and sucked a companion of her own sex, her own mate, and, after only a few days’ fast, her own young, and then sucked her own eggs. During its larval and pupal stages of existence, the Reduvius covers its body and limbs with dust and any other refuse which it can find. In this manner it disguises its form so completely that it scarcely looks like an insect. Occasionally it seems to be dissatisfied with its coat of dust, throws it off, and sets to work at a new one.