94 



Marvels of Insect Life. 



out its long wings and longer legs. There are about a thousand species of crane- 

 fly known, but only two others occur in our islands. The Chinese rejoice in a species ^ 

 which measures, when the wings are expanded, four inches across. 



The Transformations of Insects. 



It is well known that such Insects as butterflies, moths, bees, beetles, and flies 

 pass through four well-marked stages of existence, and among those who are not 



entomologists it is generally assumed that 

 all Insects exhibit the same abrupt or 

 apparently abrupt changes from stage to 

 stage. As a matter of fact, however, there 

 are great numbers of Insects whose course 

 of development from the egg to the adult 

 winged state shows none of these strong 

 contrasts ; their progress is as gradual as 

 that of a man from helpless infancy to full 

 maturity. In reality the same is true of all 

 Insects, but where the food and the habits 

 of the adult differ from those of the infant, 

 it is necessary that the mouth-parts and 

 the digestive system should be reorganized, 

 and there has to be interposed a resting 

 period in which no food is indulged in and 

 no muscular activity undertaken. To take 

 a familiar illustration, the caterpillar lives 

 upon leaves which have to be finely cut 

 and masticated. For this work cutting 

 mandibles are requisite, and a long, com- 

 plex digestive tract for the proper assimila- 

 tion of the food. The butterfly, which is 

 the ultimate stage of the caterpillar, takes 

 nothing but a little nectar from the flowers, 

 and to obtain this its mouth-parts have to 

 be reorganized and remade into a tubular 

 sucking organ. The digestive tract is 

 correspondinglv reduced in size and com- 

 plexity, and considerable change takes 

 place in the nervous system. When we 

 consider the great changes thus implied, we see a reason for the resting stage 

 known as the chrysahs. 



Now, if we consider such an Insect as a grasshopper, which takes the same 

 food at maturity as it took in infancy, we see that there is no necessity for a radical 

 change in the mouth-parts and the digestive system. Therefore, there is no 

 resting stage — the grasshopper is active throughout its existence, and the wings 

 are developed gradually. 



' Tipula brolxlit^nawia. 



Plioto by I [H. Biistin. 



Daddy Long-legs. 



The length of leg, which appears so ridiculous when the fly is 

 sprawling over our window-panes, bears a different aspect when 

 the Insect is seen making its way easily over the grass. The long, 

 slender limbs pass between the shoots whilst the feet touch the 

 ground. The eggs are laid in grass-land, and the grub — well 

 known as the leather-jacket — feeds upon the roots of grasses 

 and other plants. 



