-O THE INSECT WORLD. 



its Skin it loses the tube, two appendages resembling an ass's ears 

 bein. for the pupa whit the tube was for the larva, the openuig o 

 thes? ears being held above the surface of the water From this 

 pupa the perfect insect will emerge; it is developed ittle by little 

 and the principal members maybe distinguished under the transparent 

 membranous skin which envelopes it. 



When the insect is about to change froni the pupa state ,t lies on 

 the surface of the water, straightening the hind part of its body and 

 extending Itself on the surfaci of the water, above which the thorax 

 fs raised^ Before it has been a moment in this position, .ts skin 

 splhs between the two breathing trumpets, the split mcreasmg very 

 ranidlv in lensfth and breadth. . c .^ .-x 



^'' It leaves uncovered," says Reaumur, "a portion of the thorax 

 of the gnat, easily to be recognised by the freshness of its colour, 

 which I gr;en, and different from the skin m which it was before 



^""^'Kn is the split is enlarged-and to do so sufficiently is the 

 work of a moment-the fore part of the perfect msect is not long m 

 showing itself; and soon afterwards the head appears, rising above 

 theTdges of the opening. But this moment, and those which follow 

 until the gnat has entirely left its covering, are most cntical, and 

 Then it is^exposed to fearful danger. This }-^-Xtto^^y^\tr 

 in the water, is suddenly in a position m which it has nothing to fear 

 so much as water. If it were upset on the water, and the water were 

 toTuch ks thorax or body, il would be fatal. This is the way 

 in which it acts in this critical position-As soon as i has got out 

 its head and thorax, it lifts them as high as it is able above the 

 opening through which they had emerged, and then draws the 

 posterior part of its body through the same opening; or rather that 

 part pushes itself forward by contracting a little and then lengthening 

 again, the roughness of the covering from which it desires to extricate 

 itself serving as an assistance. -, . .u 



"A larger portion of the gnat is thus uncovered, and at the same j 

 time the head is advanced fkrther towards the anterior end of the || 

 covering ; but as it advances in this direction, it rises more and mor^,^ 

 the anterior and posterior ends of the sheath thus becoming quite ; 

 empty. The sheath then becomes a sort of boat into which the i 

 water does not enter; and it would be fatal if it did. The water 1 

 could not find a passage to the farther end, and the edges of the 

 anterior end could not be submerged until the other was considerably 

 sunk. The gnat itself is the mast of its little boat. Large boats, 

 which pass under bridges, have masts which can be lowered ; as 



