FIELD BOOK OF INSECTS. 



be more convenient for the layman,-a liberty somewhat 

 to be pardoned by reason of the fact that few technical 

 books agree among themselves. Brues and Melander's 

 Key to the Families of North American Insects is the best 

 recent, detailed treatment of the subject. 



Concerning Much against my inclination, I have 



Measurements given measurements in inches. This has 

 made it necessary to use various fractions 

 and these are awkward things to get at on ordinary rules 

 In using measurements, it must be remembered that there 

 ' considerable variation in the size of the same species 

 and, even where upper and lower limits are given, these 

 limits may be overstepped by exceptional individuals or 

 by many individuals in exceptional seasons or localities 

 Ln those illustrations which are not natural size the aver- 

 age size of the insect is usually indicated by a line near the 

 ngure. 



Growth Thus earl y e it said that insects do not 



grow after they have attained wings 

 Small, winged flies do not grow to be large, winged flies 

 even though the same kitchen window frequently contains 

 There are two main sorts of life histories called 

 respectively Incomplete and Complete Metamorphosis 

 Insects having the first kind, grasshoppers for example 

 3k, when they leave the eggs, more or less like minia- 

 tures of the adults except that they have no wings even if 

 the adults have. Insects of the second sort may be as 

 different, when they hatch, from the adult as a caterpillar 

 is from a butterfly, and they usually go through a resting 

 (pupal) stage before they get wings. Young insects may 

 said to grow by leaps and bounds, not gradually 

 ey are largely covered, like lobsters, by a shell which 

 1 not stretch. All the flesh is inside of this shell, and 

 the quantity of this flesh gets too laive the shell 

 splits, usually down the back; the insect emerges, swells 

 out, and his new skin again hardens by reason of the 

 :hitm it contains. This process is repeated several times 

 before adult life is reached. The number of molts is 

 usually very definite for each species and sometimes an 



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