ENTOMOLOGICAL. 



51 



with which it works the silk, made from vegetable matter, 

 which once suggested to a thoughtful Persian the beauti- 

 ful proverb that " time and 

 patience will convert the 

 mulberry leaf into satin." 

 This is a typical caterpillar, 

 and we must content our- 

 selves with its study, though 

 a large family await our 

 examination. 



Observe its exquisitely 

 formed tracheae and spira- 

 cles, the organs through 

 which it receives the outer 

 air, passing through its en- 

 tire body. What care has 

 been bestowed on these tiny openings called " spiracles," 

 from the Latin spiro, "I breathe" running along the 

 sides of its body ! There are six pairs, and there is reason 

 to believe they open and shut just as our lungs contract 



Trachea of an insect (a) compared 

 with spiral vessels of a plant (&). 



Spiracle of Dytiscus (water beetle), greatly enlarged. 



and expand every time we take in and give out the air 

 we breathe. But what a marvellous display of wisdom is 

 here ! Look at the trachese so called from the Greek 

 for " windpipe," Coils and coils of fibre secure a safe 



