256 INSECT WATER TRESPASSERS. 



bodies and very long legs, and in some, such as 

 Hydrometra stagnorum, both the body and legs are so 

 exceedingly delicate, that the insect looks almost like a 

 shadow flitting over the surface of the water. Take 

 half an inch of a fine needle, support it on four black 

 hairs, and stretch out two hairs in front of the head, 

 stain the needle black, and there is a very fair imita- 

 tion of the Hydrometra. 



Slight and delicate as is this creature, it is a very 

 predacious one, and I have seen them seizing and 

 carrying off their prey quite as ferociously as f ' Daddy" 

 used to do. The Hydrometra feeds almost entirely 

 upon the small insects that fall into the water. It 

 comes gliding up to them like a shadow, and almost 

 as silently, picks up its prey with the very ends of its 

 fore legs, and, holding the captured insect out at the 

 full stretch of its legs, makes for the shore, where it 

 sucks the juices, and then goes off in search of more 

 prey. 



It is worthy of remark, that the process of sucking 

 seems to have no effect whatever upon the outward 

 aspect of the victim. I have seen plenty of water 

 gnats killed and sucked by the water boatman, and 

 when the exhausted prey is rejected, the keenest eye 

 cannot detect any change of form. It could at once 

 be " set " and dried, and in that case would look as 

 well as if it had been killed by poison or boiling 

 water. 



