4 GENERAL CONSIDERATIONS. 



unlike the perfect insect as possible ; for what can he more unlike than the caterpillar and 

 butterfly? How disgusting the one, as it crawls like a reptile; and how beautiful the 

 other, as it Hits in the air like a bird ! 



From the egg, the fust slate in which the inject appears is the larva. This stage of 

 existence is characterized by the vermiform shape and construction of their bodies; and 

 it is a stage which attracts our attention more frequently than that of the perfect insect, 

 and it is one in which it usually commits a greater amount of injury than in the perfect 

 stage : it is, too, in this stage that the agriculturist can more effectually exterminate these 

 his foes. The term larra i-. applied generally to the immature butterfly or caterpillar. Grubs 

 are white, soft-bodied animals, which are immature beetles ; while maggots are immature 

 flies, or belong to the dipterous order of insects. All, however, are the analogous re- 

 presentalh es of the different orders in the same stage of development, or that stage during 

 which the insect grows and frequently easts its integuments : it devours immense quanti- 

 ties of food, and is often very destructive to the foliage of vegetables. When it has reached 

 its development for the larva stage, it ceases to eat, wraps itself in a mantle, simulates 

 death, but is really undergoing internal changes preparatory to a higher stage of develop- 

 ment. In its mantle it easts its old skin, which it presses down into the. lower part of its 

 envelope, and soon appears in a livery peculiar to the pupa stage. The time during which 

 it is confined to this stage varies with every insect : in some it is brief; in others, it is long. 



Inlets are composed of thirteen segments, including the head ; but an obscurity often 

 arises from the consolidation of segments, and often produces thereby & disproportionate 

 development of certain parts. The three segments immediately behind the head correspond 

 to the prot/iornx, mesotlvorax, and mctufhoraT of the insect ; and these bear the three pair of 

 legs, provided the larva possesses legs. These are persistent, and hence are called true legs, 

 to distinguish them from the abdominal legs, prolcgs or props, which are caducous, or are 

 never transmitted to the perfect insect : they are peculiar to the larva. The mouth-pieces 

 or oral organs frequently differ in the different stages also. These are sometimes designed 

 for suction in the larva, while the perfect insect is provided with jaws for mastication ; 

 hence, in such cases, the nature of the food is changed : in other cases the provisions for 

 taking food are the same in both stages. 



The larva; grow rapidly, as a general fact, insomuch that the whole structure of the 

 animal indicates provisions subservient to this result : they are provided with strong and 

 efficient organs of manducation ; their digestive organs are very large and capacious ; the 

 function of digestion is rapidly effected, and the consumption of food is immense in pro- 

 portion to the weight of the body. It is stated that flesh-flies increase two hundred times 

 their weight in twenty-four hours. Count Daxdolo remarks that the weight of the silk- 

 worm, when first hatched, is about one-hundredth of a grain, or it requires one hundred 

 of them to weigh a grain : after the first moulting, one hundred weigh 15 grains; after 

 the second, the same number weigh Si grains ; after the third, their weight is 400 grains ; 



