296 INTRODUCTION TO ZOOLOGY chap. 



Type : The Blue Dragon-fly {Aeschna cyaneo). 



Aeschna is one of the largest and most striking British 

 Dragon-flies, frequently to be seen flying with swift powerful 

 darts by the side of streams and ponds, and even in gardens, 

 far from any water, flying right over the tree tops when 

 alarmed. 



Fig. 219. — The Blue Dragon-fly (Aeschna 



General '^^ winged insect has a long tapering body 



Form and and large wings (Fig. 219). It is beautifully 



Colour, coloured. The head has greenish-blue compound 



eyes, meeting for some distance in the middle line, and in 



front of these are three simple eyes or ocelli in a straight 



line ; the antennae are minute bristles projecting forwards. 



On each side of the thorax is a green spot, just in front of 

 the attachment of the first pair of wings. Greenish spots also 

 run in pairs down the dark-coloured abdomen of the male, 

 and yellow spots similarly mark the female, the two spots on 

 each of the last two segments becoming confluent. On the 



