INSECT A : NEUROPTERA 



305 



b-- 



Genus 3. Orthetrum. Wings clear and unstained, the abdomen 

 may be narrower than in Libellula or as broad. The 

 abdomen in the male is blue, in the female brown. 



Sub-family 2 : Aeschnidae. 



The Dragon-flies of the sub-family Aeschnidae are large 

 forms in which, as in the Libellulidae, the eyes meet on the 

 head for some distance ; but the three ocelli are in a straight 

 line on the front of the head, and the abdomen is very long 

 and narrow. The larva also is larger, with a relatively 

 longer abdomen and stronger legs than in a Libellula larva. 



Genus 1. Aeschna. The base of the inner margin of the hind 

 wing on the male is characterised by having a sharp 

 point. The male is usually brown, spotted with blue, 

 though it is nearly all brown in the common A. grandis. 



2. Anax. Large, beautifully bright 

 forms, the body of the males 

 blue, and of the females green, 

 with a long irregular black line 

 down the back of the abdomen. 



3. Cordulegaster. The name is 

 derived from the Greek cordule 

 = a club, so called from the 

 shape of the abdomen, which is 

 thin in the centre, and thicker 

 at both ends. The body is 

 greenish black, with transverse 

 yellow markings. 



Sub-family 3 : Agrionidae. 

 The members of this sub-family are 

 relatively small forms, and the eyes are 

 wide apart and large. The abdomen is 

 slender and usually brightly coloured, 

 the wings very narrow, transparent, and 

 uncoloured, except for the small dark 

 patch or stigma present on the front of 

 each wing in both sexes. There are 

 only two small cross veins in the space 

 between the node of the wing and its base. The larva is a 

 slender, greenish-coloured little creature, with three delicate 

 VOL. i x 



FIG. 228. 

 One of Agrionidae. 



Empty nymph skin ; />, 

 imago which has emerged 

 from a ; n, node of wing. 



