THE INSECT WORLD. 



153 



powerful beak and sucking their juices. There are other species 

 of the same general appearance common everywhere, and some 

 even maintain themselves in our cities, feeding upon the larvae 

 injuring shade-trees. I have noticed certain of them in New 

 Brunswick destroying the larvae of the elm-leaf beetle in large 



Fig. 114. 



The wheel-bug, Prionidus cristatus, in all its stages; natural size. 



numbers. Taking it altogether, we find in this family mainly 

 forms that are beneficial to the farmer. 



There are a few other common species, also predaceous m 

 character, but much smaller and more slender than the pre- 

 ceding, belonging to the family Nabidce, Our common species 

 of the genera Nabis and Coriscus are yellowish in color, flat- 

 tened above and rather roughened, with long legs, but other- 

 wise resembhng in head and beak the usual predaceous form, 

 except that the beak is longer and more slender. They are 

 found on flowers and leaves, preying upon almost anything that 

 they can conquer. 



