136 THE ANIMAL KINGDOM. 



learns accuracy of observation ; it learns what it never for- 

 gets the vast importance of little things; and what the eye 

 sees often the heart feels. Find out, therefore, a very short 

 and oblique vein, between the cubital and \hz prabrachial, 

 down close to the dot of the radial, and the space thus 

 bounded at the base is called the prabrackial areolet, and 

 its minute size and position in every one of the genera is 

 decisive of the family. 



Pass on now to the legs, and remark the spines on the 

 femora and metatarsus ; they will also serve to show the 

 species, for in some Dolichopus there is invariably but 

 one spine, in others four or two, and in some there are a 

 double row. 



THE OPOMYZA 



is one of a family group called Geomizides ; they frequent 

 recent or decaying vegetable substances, also our windows, 

 and are very present little unknown friends. We may know 

 these by their spotted wings, by the tawny body, yellow head, 

 thorax striped with three pale lines ; the abdomen has a dark 

 dorsal stripe or dark bands ; they abound in herbage. Now 

 examine the head and wings. 



The head is broad and eyes large ; the antennse, like those 

 of a true Musca, three joints drooping, the third round and 

 large; the arista long, slender, hairy, and with a small joint 

 you will hardly see unless the head is in profile. 



The thorax is bristly ; the abdomen has seven segments 

 a little hairy ; and then pause to look at the wings, and com- 

 pare them with those of Dolichopus. 



You will first observe two transverse veins slightly 

 clouded; the prabracldal straight; the discal transverse- 

 hindermost, and joining the pobracliial vein to the prtz- 

 brac/iial; the cubital and radial veins are quite straight. 



CHLOEOPS. 



A mischievous little Ply; and the farmer will be in- 

 terested in seeing the parent of that larvae which sometimes 

 commits such havoc in his wheat-field. In England there 

 is a disease known as the gout, from the swelling it occasions. 



