146 Natw&k's teachings. 



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 conceal- 

 ment 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 Beduvim personalis. 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 Reduviidse 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. 



One of these creatures, as it appears when covered with its 

 dusty coating, is seen in the upper left-hand corner of the 

 illustration. It is slightly magnified. 



Below the Reduvius is the common Cuckoo-spit (Aphrophora 

 spumaria), whose frothy masses are so plentiful in our hedge- 

 rows and gardens. 



If one of these masses be carefully opened, there will be 

 found in it a little green creature with small, round, dot-like 

 eyes. This is either the larval or pupal state of the Frog- 



