32 BritisJi Dragoiiflics 



to depend almost entirely on the environment. If a 

 nymph is hving on the mud it is brown ; if on a dead 

 stick ahnost black ; while should it make its home 

 amongst the weeds, it clothes itself in a dress of 

 harmonious colouring — green, and sometimes of the 

 brightest emerald tint. This chameleon-like adaptabilit}- 

 to its surroundings no doubt serves a double purpose, 

 that of hiding the n}'mph from its enemies, and at the 

 same time enabling it, without being suspected, to 

 approach within striking distance of its prey. 



Probably also form, no less than colour, conduces 

 materially to the ^\•ell-being of the young Dragonfly. 

 Those who search for n}'mphs know only too well how 

 difficult the /Eschnas are to distinguish from the 

 broken bark on a water-logged stick, or how well a 

 Caloptcryx is hidden amidst the roots of the reeds. 

 Amongst the dead leaves and rubbish at the bottom of 

 a pond a Lihclliila, a Sympctriiiii, or a Coniulia looks 

 as much like a bit of rubbish as the}-, whilst an 

 Agrionine amongst the weeds almost defies detection. 



Under ordinary circumstances, all n}'mphs walk 

 slowl}', indeed, rather stealthil}-, amongst the weeds or 

 along the bottom of the pond or stream, but when 

 disturbed or aroused by the near presence of some 

 living creature which appears suitable for food, they can 

 progress in a ver\^ different manner and with much 

 greater speed, though the method emplo}'ed to obtain 

 this exceptional speed is not the same in both of the 

 great divisions of the Odoiiata. To understand this it 

 will first be necessary to examine a little into the 

 structure of a typical n\-m[:)h from each division 

 (Figs. 1 1 and \2). 



