Page:Jardine Naturalist's library Entomology.djvu/309

Rh there is no trace of them, except in the costal alone, which loses itself in a scarcely perceptible stigma." The value of the generic characters afforded by the modifications which the figure of the cells undergoes, may be inferred from the fact stated by M. Jurine, that he could, in most cases, determine the genus of a hymenopterous insect from the inspection of the wings alone. As among the Hemiptera, the inferior wings are more or less closely united to the superior when in action, but this is effected by a different kind of mechanism. Along the anterior edge of the secondary wings is placed a series of very fine hooks (hamuli,) which attach themselves to the hinder margin of the primary pair, and a continuous surface of some extent is thus presented to the air. From the preceding details it may be inferred that the Hymenoptera possess great powers of flight. It is in fact one of the orders in which that power has reached its maximum; all the necessary conditions being found united. The great distances to which bees fly in search of honey, often against a strong wind, are well known; and even when they are loaded with pollen, or other substances—with "treasures sucked from buds and bells"—the rapidity of their aërial movements appears in no degree retarded. The humming noise which many of them emit is not produced by any organs specially formed for that purpose, as among the Hemiptera and Orthoptera,