214 THE BRITISH NATURE BOOK 



Sub-order vii. HETEROMERA (" Unequal-jointed "), 



because the tarsi of the front and middle legs are five-jointed, the hind-tarsi 

 four- jointed. 



Family : Tenebrionidce. 



Usually black. 



Blaps mucronata (the Churchyard Beetle) (Fig. 150). About -1 inch 

 long. Dull black ; pointed abdomen ; wingless. Found in cellars, kitchens, 

 and dark places at night. Common. 



Opatrum sabulosum (Fig. 151). Length about J inch. A dull shabby 

 brownish black. Scantily covered with grey down. Found under stones in 

 sandy places. 



Tenebrio molitor (the "Mealworm" Beetle) (Fig. 152). Length about 

 i inch. Black; finely pitted. Found in flour mills, rotten wood, and in 

 stale flour. The larvae, known as " Mealworms," are used by bird fanciers 

 as food for young birds and soft-bills. 



Helops striatus (Fig. 153). About \ inch. Black, with fine lines on the 

 elytra ; legs have a slight reddish tinge. Found under bark of pine trees. 



Cistela murina (Fig. 154). Length | inch. Black head and shoulders ; 

 elytra clay-yellow. Found on flowers in seacoast places. 



Orchesia micans (Fig. 155). Brown-black, with fine silky down. Lives 

 on fungi. A type of a genus of hopping beetles. 



Melandrya cardboides (Fig. 156). Length about inch. Black, with bluish 

 lustre ; elytra thickly pitted ; feet tipped with orange. Common on beech 

 or oak. 



Lagria hirta (Fig. 1566). The only British species of this genus. Length 

 under | inch. Pear-shaped. Blackish body; yellow elytra. Soft, covered 

 with light down. Found on flowering bushes. 



Pyrochroa serraticornis (Fig. 157). Length %-$ inch. Wedge-shaped. 

 Dull red elytra ; thorax and head covered with orange down ; black legs and 

 antennas. Found in grassy shady places or under bark of trees. 



Meloe violaceus (the Violet Oil Beetle) (Fig. 158). Length very variable, 

 |-i| inches. Black, with a very pronounced bluish lustre. Wingless and 

 soft-bodied. The elytra are short and cover only the upper part of the 

 abdomen. The female is much stouter than the male. Common in grass. 



These beetles have a very curious life-history. Their name " Oil Beetles " 

 comes to them from the acrid, offensive oily fluid which is secreted at the 

 joints of the femora and tibiae of their legs. This contains cantharidin, an 

 extremely caustic substance, which is an almost perfect protection against 

 birds and other natural enemies, and accounts for the freedom with which 

 they feed by day on open ground and for the lack of wings. 



The female lays her eggs in a sticky mass in a hole which she excavates 

 for them. When the larvae hatch out (in about a month), they make their way 



