108 



Smith and Pritchard: Odonata 



MS** 



Fig. 4'1 '. Generalized habitat of Cordulegasler dorsal is: Below, 

 naiad with protective coat of algae on stream bottom; above, 

 exuvium and female ovipositing in stream bed (Kennedy, 1917). 



the intromittent organ on the second abdominal seg- 

 ment of the male and to receive the sperm (fig. 4:9). 

 The male frequently accompanies the female while 

 she oviposits (fig. 4:8). 



The naiads (fig. 4:36) are strikingly different in 

 appearance from the adults. They are short and com- 

 pact as compared to the adults and have smaller 

 heads. They are cryptically colored and breathe by 

 means of gills. In the Zygoptera these consist of 

 three caudal lamellae; the Anisoptera have rectal 

 gills. The most striking feature of the naiad is .the 

 development of an extensile labium. It is long and 

 jointed so that it can be extended quickly to capture 

 prey. 



Most Odonata develop in permanent fresh water. 

 A few are semiaquatic in that they occur in bogs; 

 others occur in saline water, and some with short 

 life cycles can develop in temporary waters. They 

 are found in ponds, lakes, streams, tanks, rivers, and 

 canals of all sizes and descriptions. Although the 

 naiads are aquatic the adults sometimes range many 

 miles from water. 



The eggs are laid in various ways (fig. 4:7). They 

 may be simply dropped into the water, or they may be 

 attached to objects in the water. In a few cases they 



are deposited in long gelatinous strings or masses. 

 More often the eggs are inserted in soft plant tissue 

 beneath the water. In some cases the females go 

 beneath the water to reach suitable ovipositon sites. 

 A few oviposit in twigs above the water. 



The naiads of all Odonata are predaceous like the 

 adults. They are attracted to their prey by sight and 

 if it is not too large it will be seized by an extension 

 of the labium. The climbing naiads, such as most 

 Zygoptera and Aeshnidae, hide in beds of submerged 

 vegetation and actively pursue their prey. An aeshnid 

 naiad may sometimes sight its prey at a distance of 

 several inches and slowly stalk it until within striking 

 distance. Other naiads, such as those of the Libellu- 

 lidae that sprawl on the bottom, are very sluggish 

 and do not strike until the prey comes within reach 

 of the labium. These sprawlers are frequently covered 

 with a camouflage of algae or a layer of silt. The 

 naiads of the Gomphidae burrow into the bottom sand 

 or mud so that only the tip of the abdomen reaches 

 the water. After about ten to fifteen instars and a 

 period from less than one to five years the naiad is 

 fully grown. It then crawls out of the water and at- 

 taches itself to some suitable object. The adult then 



Fig. 4:8. Damselfly pairs (Ischnura denticollis) ovipositing 

 (below) and in resting position (above) (Kennedy, 1917). 



