lABViE or WATEE-FLIES. 261 



extract the nectai' from flowers ; but the female Gnat is always 

 ready to make an addition to this fare by sucking the blood 

 of animals, not even oiriitting, alas ! that of man. 



The female Gnat's method of laying her eggs is exceedingly 

 curious and interesting. She deposits them upon the surface 

 of stagnant water. To do this, she looks about for some piece 

 of floating grass, stick, or the like, upon which she settles. 

 She then places her fore pair of legs upon her temporary 

 raft, and her intermediate pair either just touching the water 

 or else upon the extreme edge of the raft, while she crosses 

 her hind-legs ready to receive the egg she is about to lay. 

 This egg, which is oblong and narrower at one end than the 

 other, she holds until she has brought forth a second and 

 has joined it, by means of the sticky substance with which 

 it is surrounded, to the first. She thus continues to lay her 

 eggs and fasten them together until they number from 200 

 to 300. All the eggs are glued side by side with their 

 narrower ends uppermost, and so a kind of unsinkable boat 

 is formed, which is slightly concave above and convex below. 

 This curious "boat" will stand a great deal of very rough 

 weather without running any risk of going to the bottom. If 

 it is pushed forcibly under the water, it will rise again to the 

 surface in the proper position immediately upon the removal 

 of the pressure. Neither a very heavy shower nor the pouring 

 of a considerable quantity of water upon it will sink it : its 

 buoyancy and self-righting power are remarkable, and quite 

 worthy of the notice of makers of lifeboats. During favour- 

 .able weather the eggs which form the " boat " hatch in a few 

 days. A kind of small door opens at the lower end of each 

 egg, which closes again after the exit of the young larva 

 into the water. 



The larvse of Gnats are curious-looking little creatures 

 (Fig. 160) ; they have rather large heads, very large thoraces, and 

 elongated bodies, with a curious breathing arrangement near 

 the extremity. This bi-eathing aiTangement consists of a small 

 tube, which is fixed to the eighth segment of the body. "When 

 the creature wishes to take in a fresh supply of air, it pro- 

 trudes the end of this tube above the surface of the water, and 



