INTRODUCTION TO ENTOMOLOGY. 13 



perfect state, but is not fully developed either in its limbs 

 or functions. 



Imago signifies the image, the likeness, or an example 

 of the perfect insect. The appropriateness of the scientific 

 names for the first and third stage does not seem very 

 clear, but there is no doubt of the convenience of having 

 some one term by which each different stage of the life of 

 any insect may be described, and these are the words that 

 have been adopted. In the following pages some detail 

 is given of these three successive stages of development : 

 Larva, maggot, grub, caterpillar, &c. If an insect egg 

 about to hatch is held against the light, or examined as a 

 transparent object by means of a strong magnifier, it will 

 be seen that there is a speck inside which increases in 

 size and becomes more regular in shape daily until it is 

 too large for the egg to contain, when it breaks through 

 this thin film which serves as an eggshell, and often begins 

 life by eating it. This is the larva. It is usually hatched 

 from an egg, but sometimes is produced alive (as some 

 fly -maggots during the summer months). 



When it is coloured and has many feet it is usually 

 called a caterpillar. White, fleshy larvae, such as those 

 of many beetles or flies, are commonly known as grubs or 

 maggots ; such as resemble the parent insect are usually 

 known by the name of this insect ; but the term of 

 "worm" or "slug" is objectionable, as it leads to con- 

 fusion. 



Larvae differ very much in appearance; some are 

 legless, cylindrical, or tapering at one end, blunt at the 

 other, with the head (which is soft and furnished with 

 hooks by way of feeding apparatus), capable of being 

 drawn some way back into the maggot ; many fly-maggots 

 are of this kind ; some larvae are legless, or with a mere 

 rudiment of a pair of legs on the three rings behind the 

 head, fleshy, smallest at the tail, and furnished with 

 distinct head and jaws ; such are some kinds of beetle and 

 wasp-grubs; others are strong and fat, a few inches in 

 length, with three pairs of legs, well developed as the 

 cockchafer grub. 



