362 THE NOTACANTHA. 



third joint, which is in reality composed of eight 

 distinct joints, so that the whole organ consists of ten 

 articulations. 



This handsome Fly, and several others agreeing 

 with it closely in general structure, are found abun- 

 dantly in the spring and summer in the neighbourhood 

 of water, where their vigorous wings enable them to 

 fly rapidly from flower to flower in the sunshine, 

 seeking the honeyed juices which constitute their sole 

 nourishment. As might almost be expected from the 

 predilection evinced by this Fly for the vicinity of 

 water, it is aquatic in its preparatory states. The 

 female deposits her eggs on the lower surface of the 

 leaves of the water-plantain (Alisma Plant ago) , which 

 forms such a common ornament of the borders of our 

 ponds and still rivers. The larva which proceeds 

 from these eggs is a curious creature, resembling in 

 its form a very long, jointed fish ; it is slightly flat- 

 tened, pointed at the anterior extremity, broadest 

 before the middle, and then tapers off gradually to 

 the tail, the hinder segments, and especially the ter- 

 minal one, being considerably longer than those in 

 the anterior part of the body. In moving about in 

 the water, this larva bends its body into the form of 

 an S, and then by striking out forcibly, contrives 

 to swim slowly along; its appearance when thus 

 engaged is very curious, for its segments being en- 

 closed in a firm skin, it can only bend its body 

 at their points of junction, and this angular flexure 

 gives its movements a singularly convulsive appear- 

 ance. As a general rule, however, the larva appears 

 to think that all this exertion is by no means con- 

 ducive to its comfort : it is usually seen floating lazily 

 at the surface of the water with its head downwards, 



