Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomolo00smit Year: 1906 62 AN ECONOMIC ENTOMOLOGY. until ready for the change to the atlult. Then they crawl up the bteni of some water plant, or upon a projecting stone, and soon the skin splits and the imagos emerge. A few minutes suffice to harden and dry the newly-developed adults, then with spread wings they sail away on a new career, in a new medium. In habit the larvae are as predaceous and voracious as the adults, and their prey consists of any aquatic f
Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomolo00smit Year: 1906 62 AN ECONOMIC ENTOMOLOGY. until ready for the change to the atlult. Then they crawl up the bteni of some water plant, or upon a projecting stone, and soon the skin splits and the imagos emerge. A few minutes suffice to harden and dry the newly-developed adults, then with spread wings they sail away on a new career, in a new medium. In habit the larvae are as predaceous and voracious as the adults, and their prey consists of any aquatic forms which they can cap- ture,—mosquito larvae forming quite a staple article of diet. It jas been already indicated that they are not very active creatures, and prey is captured by simply waiting in the mud or on a mossy stone until it comes within reach. Their color renders them almost in\ isible under such conditions, and nature has furnished a remarkably extensile mouth structure, by means of winch they are able to reach out some distance and seize whatever creature may be passing near. It is the labium, or lower lip, that is modified for this plirpose, and is supplied with a double hinge which can be straightened out rapidly to bring into play a pair of large, slender, and pointed jaws at its tip. When this structure is retracted it is invisible, covering the other mouth parts entirely and hiding them. The term 'mask' has therefore been applied to it. Oviposition varies with the species, and is interesting. The sexes pair during flight. The male has the organs of copula- tion at the base of the ab- ^^' domen, while the opening of the testes is at the tip. Before pairing he fills the seminal pouch at the base of the abdomen, then grasps the female by the neck with a pair of anal claspers, and she curves up the tip of her abdomen into contact witli the opening to the seminal duct of the male. As the eggs are fertilized the pair descend to the surface of the water, the fema
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