3 oi4 THE JOINTED ANIMALS 



however, to return to its accustomed place at the surface. During growth, the 

 larva undergoes a series of three molts before reaching its full size, the newly- 

 clothed insect escaping from the old skin through a longitudinal slit behind the 

 head. At the fourth molt emerges the pupa, which is a very different looking 

 creature from the larva, showing the cases for the antennae, wings, and legs of the 

 adult, while from the sides of its thorax project a pair of tubes, analagous to those 

 of the larval tail, and like these carrying the apertures of the tracheae. By means 

 of its jointed abdomen the pupa jerks itself about in the water in company with 

 others of its kind. At the appointed time a longitudinal slit occurs on the back 

 behind the head, and, extricating itself from its pupal case, the adult gnat appears 

 on the surface of the water, where under favorable conditions its skin hardens and 

 its wings unfold, while it floats upon the water using its discarded clothing as a 

 raft. If this time of danger be successfully overcome, the insect takes wing and 

 joins its companions in their mazy dance; but, before acquiring strength to do so, it 

 is at the mercy of every wave or gust of wind, and if once swept back into the 

 water, its chances of survival are small. The before-mentioned banded gnat may 

 be distinguished from other British species by its large size, its spotted wings, and 

 striped legs and abdomen. The common gnat (C. pipiens), which fs often abun- 

 dant in houses in the autumn, is much smaller and without the ornaments char- 

 acteristic of its larger ally. 



Travelers in the tropics are so familiar with mosquitoes that nothing we can say 

 can add to their knowledge of the subject. But to give those who have been 

 fortunate enough to avoid a practical acquaintance with them some idea of the 

 torments caused by these little pests, we quote the following passages from the 

 works of two well-known naturalists. Speaking of his sojourn at a place on the 

 Atnazons, Bates says ' ' at night it was quite impossible to sleep for mosquitoes; 

 they fell upon us by myriads, and without much piping came straight at our faces 

 as thick as rain drops in a shower. The men crowded into the cabins and then 

 tried to expel the pests by the smoke from burnt rags, but it was of little avail, 

 although we were half suffocated by the operation." Again, Emerson Tennent 

 writes that "of all the insect pests that beset an unseasoned European, the most 

 provoking by far are the truculent mosquitoes. Even in the midst of endurance of 

 their onslaughts one cannot but be amused by the ingenuity of their movements; as 

 if aware of the risk incident to an open assault a favorite mode of attack is, when 

 concealed by a table, to assault the ankles through the meshes of the stocking, or 

 the knees which are ineffectually protected by a fold of Russian duck. When you 

 are reading a mosquito will rarely settle upon that portion of your hand which is 

 within range of your eyes, but cunningly stealing by the under side of the book, 

 fastens on the wrist or little finger and noiselessly inserts his proboscis there. I 

 have tested the classical expedient recorded by Herodotus, who states that the fish- 

 ermen inhabiting the fens of Egypt cover their beds with their nets, knowing that 

 the mosquitoes, although they bite through linen robes, will not venture through a 

 net. But notwithstanding the opinion of Spence, that nets with meshes an inch 

 square will effectually exclude them, I have been satisfied by painful experience 

 that, if the theory is not altogether fallacious, at least the modern mosquitoes of 



