Dr Goring and Mr Pritchard's Treatise on the Microscope. 355 



It is at this time about a quarter of an inch in length, and swims very 

 nimbly. The colour of the head is a strong Indian yellow, with darker 

 shadings of a bright chestnut. It is more sparingly covered with hairs 

 than at a more advanced period of its age ; and the head is larger in pro- 

 portion to the size of the body, than when the creature is arrived at matu- 

 rity. In this respect it resembles the mode of growth of many other crea- 

 tures, in which the head comes to be developed and perfected before the 

 rest of the system. 



The manner in which the larva treats its prey evinces an extraordinary 

 degree of instinct. Many of the creatures on which it feeds are crustace- 

 ous about the head and back; hence their most vulnerable part is the 

 belly. This part, therefore, the larva attacks, and to accomplish its aim, 

 swims underneath the intended victim, and bending back its head, which 

 is even with the surface of its back, is enabled to reach its prey by means 

 of its jointed antennae. Its next operation is to pierce it with the mandi- 

 bles. Having thus secured its object, it immediately ascends to the top 

 of the water, and holding its prey above the surface, so as to prevent it 

 struggling, shakes it as a dog would a cat. The prey, however, of this 

 larva, is often larger than its destroyer. Its next operation is to insert the 

 piercer and sucker, which is capable of being thrust out or withdrawn at 

 pleasure. When the juices of the victims are not easily procured by suc- 

 tion and exhaustion, the serrated pair of forceps is employed to tear and 

 masticate it, and thus cause the juices to be more easily obtained. If its 

 food be plentiful, this larva arrives at its full growth in the course of 

 three or four weeks, and is then nearly opaque and thickly covered with 

 hair. It can be kept several days without food, and by this ex-inanition 

 its structure becomes considerably more transparent, while its natural 

 ferocity is greatly increased, so that it will attack and fight with creatures 

 much larger than itself, and even with its own species. It may be re- 

 marked that it studiously avoids any contest with the riepa or Water- 

 Scorpion. 



On a fine sunny day the larvse arise to the surface, and delight to bask 

 in the sun, but if watched, they remain motionless, with their claws ex- 

 tended. If.a stick, or any other substance, be presented to them, they 

 will immediately seize it, and will sometimes suffer themselves to be cut 

 into pieces before they relinquish their hold. Their bite has been con- 

 sidered poisonous by many persons, as it takes a greater time to heal than 

 other wounds of the same extent, so that caution should be used in taking 

 them. 



Touching the anatomy of this creature, it may be observed, that the 

 sucker is contained in a crustaceous sheath, and may be considerably pro- 

 truded or completely withdrawn at the pleasure of the larva. The eyes 

 are compound, but of a peculiar conformation, being composed of seven 

 oval lenses arranged like leaves upon a branch. The whole of the head 

 and thorax is curiously marked with a number of lines and spots. The 

 legs are six in number ; they are thickly set with rows of hair on their 

 opposite sides, and each is furnished with a sharp claw. The number of 



