GNAT. 3J7 
suspend itself in this position by means 
of an oily fluid, of which it has a small 
reservoir in the tail. 
Lucy, How does the oil enable it to 
suspend itself? 
Mother. Oil, you know, is much 
lighter than water, and swims on its 
surface, in a thin pellicle, or film ; to 
this pellicle the little creature attaches 
itself. 
Lucy, Do they never sink ? 
Mother, When the wind is high, and 
the water rough, the oil is disturbed, and 
they descend to the bottom ; but as they 
seem incapable of living without a con- 
stant supply of air, they frequently return 
to the surface. They continue in this 
larva state for about three weeks, when 
they become pupae. 
Lucy, And then, I suppose, they 
immediately leave the water? 
Mother, No ; they remain some time 
longer in the water to perfect their 
changes ; the stigmatae, which were at 
the tail^ are now placed at the head, and 
a 
