107 

 Smith and Pritchard: Odonata 



Fig. 4:5. Diagrom showing paired veins, fused veins, and 

 Fig. 4:2. Main wing veins of anisopterous wings. A, anal vein; principle interspaces in venation of dragonfly wing (Needham 

 al, anal loop, ar, arculus; br, bridge; C, costa; Cu, cubitus; M, and Westfall, 1955). 

 media; n, nodus; o, oblique vein; R, radius; s, subtriangle; Sc, 



subcosta, sn, subnodus; st, stigma; t, triangle (Needham and A ^-^"""^ A 



Heywood, 1929). 



to the modifications of the thorax (fig. 4:1) and the 

 special copulatory mechanism. The meso- and meta- 

 thorax are greatly enlarged and fused to form a 

 pterothorax. This pterothorax contains the large flight 

 muscles. The legs are crowded together and moved 

 forward on the thorax. They are not used for walking, 

 but they are adapted for perching and for catching 

 and handling the prey. In flight the legs act as sort 

 of a basket to catch prey. The front legs are also 

 used to hold the prey, either at rest or in flight, while 

 it is being chewed by the mandibles. The abdomen 

 is ten-segmented and carries the genital appendages 

 at the distal end. The males of all Odonata have a 

 pair of movable, unsegmented dorsolateral appendages 



^ 



Fig. 4:3. Diagram of wing illustrating principal veins and 

 their connections, sup, supratriangle; ac, anal crossing. Other 

 lettering as in fig. 4:2 (Needham and Westfall, 1955). 



Fig. 4:4. Venational characters in anisopterous wing (Gomphus 

 cavillaris). Middle fork (MF) thickened for easier recognition; 

 Ac, anal crossing; an, antenodal cross veins; b, brace vein; pn, 

 postnodal cross veins. Other lettering as in fig. 4:2 (Needham 

 and Westfall, 1955). 



Fig. 4:6. Comparative diagrams of the bases of anisopterous 

 wings, a, family Gomphidae (Ophiogomphus carolus); b, family 

 Libellulidae (Erythemis simplicicollis). Triangles striated, sub- 

 triangles dotted, anal loops wavy-lined, basal Triangle cross- 

 hatched (Needham and Westfall, 1955). 



immediately behind the tenth segment. In the suborder 

 Anisoptera there is an additional median inferior 

 appendage (fig. 4:23), whereas in the Zygoptera there 

 are two inferior appendages (fig. 4:68). Those male 

 appendages are adapted to grasp the head or thorax 

 of the female in copulation. In addition, the males 

 possess a penis on the venter of the second and third 

 abdominal segment. The female Odonata lack this 

 penis on the second and third abdominal segments; 

 however, the superior anal appendages are usually 

 simpler and reduced or vestigial. In all Zygoptera 

 and in the Aeshnidae and Petaluridae of the Anis- 

 optera, a well-developed ovipositor consisting of 

 three pairs of ventral processes is present near the 

 tip of the abdomen. In other families it is reduced or 

 absent. The well-developed male naiads show the 

 developing genitalia on the venter of abdominal 

 segment two, and in the female the ovipositor may be 

 seen on the venter of segments eight and nine. 



The male transfers sperm capsules from the genital 

 aperture on the ninth segment to the penis vesicle on 

 the second segment. In mating the male grasps the 

 female either by the head (Anisoptera) or the prothorax 

 (Zygoptera) with the terminal abdominal appendages. 

 The female then curls her abdomen forward to reach 



