CHAPTER IV 



THE LARVA OR NYMPH 



The term nymph is applied to the aquatic larvae of those insects 

 which have an incomplete metamorphosis (i.e. have no true pupa 

 or resting stage), such as Dragonflies, May-flies, etc. The term, 

 however, subserves no useful purpose, since the nymph is, bio- 

 logically, simply a larval form, and nothing more nor less. It is, 

 also, somewhat inappropriate to the appearance of these creatures. 

 We shall therefore use the term larva throughout this book. To 

 those entomologists who hold the belief that a true larva must be 

 followed by a ^m^a-stage, we would point out that such is not the 

 case. Larval forms occur throughout the Animal Kingdom (even 

 in some Protozoa). The essential condition of a larval form is that 

 it should differ sufficiently from the perfectly-formed animal to 

 require a metamorphosis in order to reach that final stage. If 

 a new term is wanted anywhere, it is rather to distinguish the 

 larvae of insects with a complete metamorphosis, since these 

 depart most widely from the "general run" of animal larvae. 



Hatching of the Larva (fig. 24). 



As a typical example, we shall select Anax papuensis Burm. 

 [177]. The eggs are placed in the soft tissues of reed-stems, just 

 beneath the water. Before hatching, the embryo (fig. 24 A) lies 

 with its head fitting closely under the pedicel or cap of the egg. 

 The head is well-formed and rounded above ; the compound eyes 

 are distinct, black in the centre, surrounded by a reddish zone. 

 All the mouth-parts can be clearly seen. The labium consists of 

 a pair of three- jointed appendages, quite separate except at their 

 extreme bases. The thoracic and abdominal segments are all 



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