INTRODUCTION. 17 



{Hydrometra Stagnorum ; Gerris Lacustris). They are known 

 to anglers as " water crickets," and are to be found at the 

 margin of almost all waters. In the earl}' season they are 

 taken very readily by the fish before more luscious morsels 

 are abundant. They are insectivorous, and at once attack 

 and crowd round any small insect which alights on the water 

 near them. 



There are also illustrated, two other Hemipiera, the Frog- 

 hopper or Cuckoo Spit {Aphrophora Alni), plate 8, fig. 91, 

 which is the " Wrentail," of Ronalds ; in the summer it hides 

 in a frothy mass on the stems of grass and plants, and in the 

 autumn, where these are near the water, this insect sometimes 

 jumps on to the surface by thousands. Another of the 

 Hemiptera is the common grass bug (plate 8, fig. 88) ; it is 

 singularly like the water measurers in general form, but is 

 found on the grass in the pastures, and along the margins in 

 countless numbers, and on a windy day is often blown on to 

 the water in thousands; there is also a green one, similar 

 in form, but slightly smaller than the one illustrated. 



We will close these brief notes with a short one on the 

 Spiders {Araneii/cr), which occupy an intermediate position in 

 the animal kingdom between the insects and the vertebrates. 

 The external differences between spiders and insects are : the 

 number of legs — a spider having eight against six in insects ; 

 the head and thorax are in one, known as a cephalo thorax ; 

 the mouths are totally different, a spider has no antennae, and 

 no body segments, the abdomen being in one piece, and the 

 eyes are simple instead of being made up of numerous lenses. 

 Internally, the nervous system, the digestive organs, and 

 circulatory systems are quite different and more highly 

 developed, and resemble in many ways those of the vertebrate 

 animals. Spiders have no larval stages. They are numerous 

 at the water side, and certainly deserve more attention from 

 anglers than they have so far received. 



