21 



these spiracles a large number of perfect spiral tabes composed 

 of elastic tissue, and passing into and all over the body of the 

 insect, branching and radiating so that the air may be conveyed 

 to every part ; to these the name of tracheae have been given. 

 We also find that most of them pass through four stages : The 

 egg ; the larvse ; the pupae ; and, lastly, the perfect insect. 



Mr. Caush then went on to exhibit a number of slides of 

 aphides, acari, pediculus, and pulei. As the views were shown 

 Mr. Caush commented upon the structure and habits of the 

 different classesof parasites shown. Some startling details were 

 given as to the rate of multiplication. For example, the pediculus 

 develops from the egg in five or six days very much like the adult, 

 and in eighteen days they are able to reproduce their kind. Thus 

 in two months two females with their offspring can produce the 

 small family of ten thousand. 



WEDNESDAY, MAY 11th. 

 (King's Apaktments, Royal Pavilion.) 



PROTECTIVE MIMICRY AS EXHIBITED 

 IN MAMMALS. 



BY 



Dr. LOUIS ROBINSON, 



Author of " JVild Traits in Tame Animals." 



At the outset let us consider what is meant by Protective 

 Mimicry. All of us who have paid any attention to natural 

 objects in our walks in the country must have noticed how 

 remarkably many insects and other creatures resemble their 

 natural surroundings. It is by no means easy to see a grass- 

 hopper among the grass, or a green caterpillar in the cabbages. 

 In the tropics many and marvellous instances are found of 

 creatures which exactly resemble dead leaves, bits of stick, lumps 

 of lichen or moss, or even worm castings and the droppings of 

 birds. If these are instances of protective mimicry, no question 

 conld arise as to the prevalence of protective mimicry among the 

 mammalia, for we find plenty of instances of warm blooded four- 

 footed beasts resembling their environment. 



