416 



THE INSECT WORLD. 



the injection of quicklime or of creosote, the application of arsenical 

 soap, &c. But it does not appear that these processes are infallibly 

 efficacious, nor, above all, easy to employ. 



Among other Neuroptera which undergo incomplete metamor- 

 phoses, we my mention, first, the genera Perla and Nemoura* 



Fig. 384. Larva of Perla 

 bicaudata. 



Fig. 385. Larva of a 

 Nemoura. 



Fig. 386. Perla marginata 

 (larva). 



(Figs. 384, 385, and 386), which flutter about the banks of rivers, 

 and settle on stones, shrubs, and aquatic plants. Their larvae are 

 naked, without cases, and always live in the water, hiding themselves 

 under stones, to watch for small insects, for they are carnivorous. 

 One sees them often balancing their bodies, holding on to a pebble. 

 They go through the winter, and only become pupae in the spring. 

 After moulting, they have the rudiments of wings. Very soon after- 

 wards the pupae leave the water, and undergo their metamorphosis. 

 The adult lives only a few days, for its mouth is not suited for re- 



* From vTjjto, a thread ; and ovpa, a tail. ED. 



