ri.YINO. 



FLYING. 



on the wing strength and resistance, in the same manner as the 

 cordagv strengthens the Bail* of a ship. The wings are elevated and 

 deomMirt by mean* of the expansion and contraction of the thorax, 

 and are connected with the respiratory movement* of the animal. 



Fig. 8. Wing* of Insect*. 



a, wing of Beetle ; *, wing of Earwig ; r, wing of Smw-Fly ; d, wing of 

 Crane-Fly ; t, wing of Common Fly ; /, wing of Midge. 



The Diptera have one pair of wings, which are elliptical in form, 

 and connected with the mesothorax. Amongst the Dijitera, we are 

 familiar with the House-Fly, and the Blue-Bottle Fly. The former 

 of these, it is well known, almost swarm in our houses, wherever 

 sugar or ripe fruits are to be found. If an attempt be made to 

 capture them by the hand, it is necessary that the movements should 

 be made with the greatest rapidity in order to effect the object, as 

 they are very watchful and agile. 



The wings of the Diptera move far too rapidly to render it possible 

 to count the number of strokes effected by them during flight. The 

 House-Fly moves with considerable velocity ; it is frequently observed 

 to play round the cars of horses, when travelling at the rate of 10 

 or 12 miles an hour. The sound by which the flight of insects is 

 accompanied does not arise, as is generally supposed, from the 

 oscillations of the wing : if such were the case, there would be no 

 difficulty in ascertaining the number of strokes. 



The weight of the large Blue-Bottle Fly is less than one grain, and 

 it hu an area of wing amounting to about one-twelfth of a square 

 inch, which is a much greater surface than is to be found in most 

 other insects. 



Fig. 7. Humble-Bcc. 



Fig. 8. Srrphiu. 



The Diptera are provided with two poisers, which are small bodies 

 occupying the situation of the posterior wings of four-winged insects, 

 and exert a considerable influence on their flight It is said that if 

 one poiser be cut off, the insect flies but a short distance with great 

 difficulty, and then (one side being rendered lighter than the other) 

 loses ita balance, and falls to the ground. If both poisers be removed, 

 it flies very unsteadily. The Crane-Fly makes use of its long legs 

 to direct ita movements in flight ; the two anterior legs being directed 

 forwards, and the posterior legs backwards. Hr. Kirby considers the 

 former to represent the prow, and the hitter the stern of a ship. 



In those- insect* which are provided with four wings, the anterior 

 pah* are attached to the mesothorax, and the posterior pair to the 

 metathorax. In the Colcopltra, the elytrum, or sheath must be 

 elevated before the wings can be unfolded. The sheath adds weight 

 to the insect, without contributing to aid its suspension in the air; 

 indeed, in flying against the wind, the progress of the animal in 

 rather retarded than accelerated by the sheath ; but by the inclination 

 of its surface the head is elevated so as to render the axis of the body 

 nearly vertical during flight. 



In the Stag-Beetla, the weight of the body is very great compared 

 with the area of the wing, being about 40 grains to T25 square 

 inch. In consequence of this diitproportion, and the additional 

 impediment of the elytra, the Coltoplera are unable to fly against a 

 strong wind. Some entomologist* maintain that none of the 

 Culeoptera can fly against the wind, but Mr. Kirby confutes this 

 opinion, and mentions a species (Meloimlha /foplia) which, he says, 

 can fly in all directions. 



The Dtrmaptera, such as the Earwigs, expand their wings like a 

 fan. They take their flight generally towards the evening. The 

 (rrylltu dome* ic HI, or House-Cricket, flies with an undulatory motion 

 like the woodpecker. 



The Diurnal Lepidoptrra, or Butterflies, fly with a peculiar undu- 

 latory movement of the body, and have an enormous surface of 

 wing compared with their weight. In the down stroke the two 

 wing* on each side lock together, producing by their combined action 



a greater effect These wings spread out like a fan, and their Kiirf.ic<- 

 rather increases than decreases as the distance from the -. 

 which the wings move increases. (Fig. 9). It is this form of wiug and 

 extent of motion, which produce the undulating flight to which 

 allusion has already been made. 



Fig. 9. Butterflies (Lfpidoptero}. 



Although in the Diurnal Ltpidoptera the surface of the wings is so 

 great with respect to the weight of the body, these insect* do not fly 

 with proportionate velocity; but ore, nevertheless, endowed with 

 sufficient speed to outstrip the schoolboy, when engaged in the chace 

 of these beautiful insects. 



The Nocturnal Lepidoptera, the Moths, possess considerable power 

 of flight The areas of their wings, instead of increasing with the 

 distance from the axis of motion, decrease, as seen in fig. 10. They 

 more nearly resemble the triangular figure of the wings of birds. 

 The anterior wing is much larger than the posterior, but they act 

 in unison with each other. The volume of the trunk of the Moths 

 is usually much greater than that of the Diurnal Lepidopttra, and they 

 fly with greater precision and velocity. Some species, the Silkworm- 

 Moth for instance, is said to travel upwards of 100 miles a day. 



Flu. 10. Moth* (Isfitloptcra}. 



The Dragon-Fly affords a good example of the locomotive organs 

 of the Nenroptera. They are furnished with four wings of a pecu- 

 liarly delicate texture, the neura resembling net-work. (Fiy. 11.) Unlike 



