SUPERFAMILY HETEROMERA Fore- and middle tarsi 5-jointed, hind tarsi 4-jointed. Larvae campodeiform, or more usually an intermediate type.
The Heteromera include 17 families whose members exhibit great diversity of form and habit but all agree in the possession of the tarsal char acters enumerated above. The two most important families are the following : The Tenebrionidae are a very large group of beetles, variable in size and form, and number about o,000 species. The familiar "black beetles" of the genus Blaps occur in cellars and outbuildings, and species of Tenebrio infest flour, meal and stored goods, their larvae being known as meal worms : most members of the family, however, occur on the ground, under stones and logs, or beneath bark.
The Meloidae (fig. 14) comprise the blister beetles and oil beetles which are soft bodied insects with the elytra (often abbreviated) not fitting closely to the sides of the body, the head constricted behind forming a neck, and the claws of the feet cleft to the base. Their life-histories are very remarkable and the newly hatched larvae are active creatures known as triungulins. In Melde and Sitaris these triungulins are dependent upon meeting certain wild bees, so, that they may be carried to their nests where they complete their development. Here they feed upon the eggs and stored honey or the latter only, and at each moult change their form and undergo a remarkable hypermetamorphosis (see INSECTS). The "spanish fly, Lytt.a vesicatoria, which yields cantharidin, is also a member of this family.
Mention should also be made of the Rhipiphoridae wh. ose. larvae are parasites of wasps, etc., and the Pyrochroidae which include the scarlet, or scarlet and black, cardinal beetles.