. Economic entomology for the STRUCTURE AND CLASSIFICATION. ' 19 Fig. tions, securing a small amount of fine shreds and scraps. These it moistens with a drop of saliva, which has great solvent properties, and then draws up the mixture by means of a sucking or pump- ing stomach. Liquids are taken in the same way, and the insects may be said to lap as well as suck their food. Flies as adults are not injurious to vegeta- tion, whatever may be said of their larvae ; but some of those fitted for piercing, like the mos- quitoes, horse-flies, and gnats, are often trouble- some or injuri
. Economic entomology for the STRUCTURE AND CLASSIFICATION. ' 19 Fig. tions, securing a small amount of fine shreds and scraps. These it moistens with a drop of saliva, which has great solvent properties, and then draws up the mixture by means of a sucking or pump- ing stomach. Liquids are taken in the same way, and the insects may be said to lap as well as suck their food. Flies as adults are not injurious to vegeta- tion, whatever may be said of their larvae ; but some of those fitted for piercing, like the mos- quitoes, horse-flies, and gnats, are often trouble- some or injurious to stock, and occasionally render regions infested by them scarcely habit- able for man. The bees seem to combine the features of ^. ^ r «u ,, u Piercing mouth structures of a horse-ny : the a biting and sucking sucking Hp is omitted. Much enlarged. mouth ; the mandibles being fully developed and the labium greatly elongated, that they may gather the nectar upon which they feed and which they store, even from the deepest flowers. This modification will be more fully described in speaking of the bees themselves. All the types of mouth structures above described and figured are derived from one original form by gradual modifications of the different pieces ; but this can be traced only in a long series of preparations from many different families and species. Next to the mouth parts, the most important appendages of the head are the antennae or feelers. These are variable in form, and in certain orders their structure indicates, unfailingly, the food habits of the insect. They are made up of a variable num- ber of joints, differing greatly in their proportion to each other, in their shape, and in their functions. Ordinarily the antennae are intended as tactile organs,—that is, for touching, as the com- mon name "feeler" indicates; but it is very certain that other sensory structures are also located there. The perception of odors, or the sense of smell, is a very
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookpublishernp, bookyear1896
