192 NATURAL HISTORY OF AQUATIC INSECTS CH. 



in, and the basin is in a moment reduced to a pear- 

 shaped body, filled with a globule of air, and reaching 

 the surface of the water only by its pointed extremity. 

 Down goes the Stratiomys larva at the first hint 

 of danger, swimming through the water with swaying 

 and looping movements, somewhat like those of 



FIG. 68. Tail-coronet of larva of Stratiomys chamaeleon. From Swammerdam, 



Biblia Naturce. 



Chironomus. When the danger is past, it ceases to 

 strueele, and floats again to the surface or swims 



^5 & *J 



upwards by a lashing movement. The pointed tip 

 of its tail-fringe pierces the surface-film, the fila- 

 ments separate once more, and the floating basin 

 is restored. 



In shallow water, the last one or two segments are 

 usually bent upwards, so as to reach the surface. 



