The Libellulidae, or family of Dragon flies, and the Ephemeridae, or May flies (Fig. 140), are the most characteristic of the Neuroptera, or veiny-winged insects. This group is a most interesting one to the systematist, as it is composed of so many heterogeneous forms which it is almost impossible to classify in our rigid and at present necessarily artificial systems. We divide them into families and sub-families, genera and sub-genera, species and varieties, but there is an endless shifting of characters in these groups. The different groups would seem well limited after studying certain forms, when to the systematist's sorrow, here comes a creature, perhaps mimicking an ant, or aphis, or other sort of bug, or even a butterfly, and for which they would be readily mistaken by the uninitiated. Bibliographers have gone mad over books that could not be classified. Imagine the despair of an insect-hunter and entomophile, as he sits down to his box of dried neuroptera. He seeks for a true neuropter in the white ant before him, but its very form and habits summon up a swarm of true ants; and then the little wingless book louse (Atropos, Fig. 141) scampering irreverently over the musty pages of his Systema Naturae, reminds him of that closest friend of man--Pediculus vestimenti. Again, his studies lead him to that gorgeous inhabitant of the South, the butterfly-like Ascalaphus, with its resplendent wings, and slender, knobbed antennae so much like those of butterflies, and visions of these beautiful insects fill his mind's eye; or sundry dun-colored caddis flies, modest, delicate neuroptera, with finely fringed wings and slender feelers, create doubts as to whether they are not really allies of the clothes moth, so close is the resemblance. [Illustration: 141. Death Tick.] Thus the student is constantly led astray by the wanton freaks Nature plays, and becomes sceptical as regards the truth of a natural system, though there is one to be discovered; and at last disgusted with the stiff and arbitrary systems of our books,--a disgust we confess most wholesome, if it only leads him into a closer communion with nature. The sooner one leaves those maternal apron-strings,--books,--and learns to identify himself with nature, and thus goes out of himself to affiliate with the spirit of the scene or object before him,--or, in other words, cultivates habits of the closest observation and most patient reflection,--be he painter or poet, philosopher or insect-hunter of low degree, he will gain an intellectual strength and power of interpreting nature, that is the gift of true genius. [Illustration: The Ant Lion and adult.] CHAPTER XI. MITES AND TICKS.