48 BRITISH INSECTS 



largest 1 is occasionally found in houses, where it is 

 said to prey on the bed-bug and other pests. When 

 immature, it has the curious habit of covering itself 

 with dust and debris. Several species of the genus 

 Nabis are not uncommon among grass and herbage. 



Members of the family Capsida have the wings 

 large in proportion to the body. The antennae are 

 four-jointed, the second joint being usually very long. 

 There are about 170 British species, most of which 

 suck the juices of plants, though a few 2 are known to 

 prey on other insects. They frequent plants of all 

 kinds s and many of them are very active. 



British water-bugs 3 are divided into four families. 

 The Nepida are represented by two species viz., the 

 common water-scorpion, 4 and the raicerlRanatra linearis. 

 The former is flat and thick-set, the latter long and 

 slender. Both, however, have the fore-legs modified 

 for capturing prey, while the abdomen carries two 

 long, slender processes, which, when brought together, 

 form a tube or syphon, through which air is con- 

 veyed to the tracheal system. Breathing is effected 

 by thrusting the tip of the syphon through the surface- 

 film into the atmosphere. 



The Naucovida have four-jointed antennae, and are 

 especially characterized by having the fore-legs 

 attached far forward on the prosternum. We have 

 two indigenous species of these, Naucoris cimicoides 

 (not unlike a small water-beetle in appearance) is 

 common, whereas Aphelocheints astivalis is rare. 



The only conspicuous British representative of the 

 Notonectida is the familiar water-boatman, 5 though 

 there is one other tiny species which lives in the mud 



1 Reduvius personatus. 2 E.g., Capsus laniarius. 



3 Series Cryptocerata. 4 Nepa cinerea. 6 $Notonecta glauca. 



