CONSIDFJtATIONS. 



I the perfect insect M possible ; for what can be more unlike than the caterpillar and 

 ' t How disgusting the one, as it crawls like a reptile ; and how beautiful the 

 other, as i^ flits in the air like a bird ! 



' rwm the «gg, the first state in which the insect appears is the larva. This stage of 

 flsiglaaee Is characterized by (he vermiform shape and construction of their bodies ; and 

 It Is • 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 ^riculturist can more effectually exterminate these 

 hblbes. The term larva is applied generally to the immatiue butterfly or caterpillar. Grubs 

 ara 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- 

 pnsentatives (^ the different orders in the same stage of development, or that stage during 

 whieh the insect grows and frequently casts 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 c«ases 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 casts 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. 



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

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

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

 to the proihorax, mesothoraa; and metathorax 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, prolegs 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 larvse 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. C!ount Dandolo 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 

 fte second, the same number weigh 94 grains ; after t!he third, their weight is 400 grains ; 



