LEAF-BEETLE. 48 LEAF-INSECT. plants. The family is an enormous one, as it cumiirises aliout 18.000 species. The f;i't ""'" jority are found in the troi)ies. but (iOO species occur in North America. The leaf-beetles are nearly all small, the potato-beetle being one of the largest of the family. The eggs, as a rule, are laid on the food plant. The hirvie of many spe- cies live on the leaves, either ex])(>sed or covered with grass. f>ome carry perfcelly constructed cases; others are leaf-miners, as the Hisjdni; still others are root-lxners and .stcnilKirers. and a few are aquatic — a remarkable diversity of habit in the larva; of a single family. The larv:r cover themselves with excrement. The most rcnnirk- able covering formed by any insect, perhaps, is that made by a tropical American leaf-beetle of the genus Porphyraspis, which lives on cwoa- palms at Bahia. The larvie are covered by a sort of bird's-nest-Iiko coating of fibres or threads attaclied to the anal extremity, which are wood fibres that have jjassed through the alimentary canal and liave been stuck together again. Some of the tropical species of this group are extreme- ly beautiful and mounted in gold are used as jewelry. With the species of temperate regions the color usually fades and becomes sordid after death. Among well-known destructive leaf- beetles are those of the genus Crioceris (see Asp ABACUS Insects), the potato-lKH'tlc, and the cucumber-beetle, and its allies of the genus Diabrotica. In California the adults injure fruit and fruit-trees, and in the East they eat the leaves of cucumber, squash, and melon vines, and the young bore into the stems and roots of the same and other food plants. (See Corx-In'SECTS.) All the Diabroticas are difli- cult insects to comV)at. Another group of agri- cultural pests in this family is that of the tlea- beetles (q.v.). The brown and black larva; of the grapevine flea-beetle feed on the up])er sur- face of grape-leaves. A well-known and destruc- tive species is the ini))orted elm-leaf beetle. (See Elm-Insects.) On tlu' sweet-potato and morn- ing-glory vines small, flattened, beautifully iri- descent leaf-beetles occur, which are gold aiul green. (See Goluen' Beetle.) Consult: Dim- mock, Standard yotiirul Ili-ilor;/, vol. ii. (Bos- ton, 1884) : Sharp. Ciimbridge 'Natural History, vol. vi. (London, ISnO). LEAF-BUG. Any hemipterous insect of the family Capsid.-e. The leaf-bugs form the largest familj- of the true bugs. They are usvially rather small, slender and delicate insects. More than 1000 species have been described, of which "iiiO in- habit the I'nited States, but there are many more und(>s<ribcd ami unnamed forms. They arc found ehielly upon the leaves of plants, but are not all true ]ilanl -feeders, and very few of them occur in sullicicnt numbers to become important crop enemies. The four-lined leaf-bug {Fcccilooapsus linriiliif:) is, however, a common garden pest, all through the Eastern, Central, and Southern United States, sucking the sap of gooseberry bushes, currants, dahlias, and many other gar- den plants. Those species which are not plant- feeders are predaceous and destroy other insects. LEAF-CTTTTER BEE. A name given to cer- tain species of solitary bees (see Bee) of the genus Jlegachile in consequence of their habit of lining their nests with portions of leaves, or of the petals of flowers, which they cut out for this pirpose with the mandibles. Iegachile centunc- lularix, a species connnon to Europe and the Inited States, uses the leaves (not the petals) of roses, fitting the pieces together so as to form one thiml)le-shaped cell within another, in a long cylindrical burrow, the bottom of each cell containing an egg and a little pollen paste. A single female will build ;iO (u' more cells and will occupy 20 or more days in the work. Mr i/acliilc acuta of the United States is a carpenter as well as a leaf-cutter, and excavates its tunnels in soft or partly decayed wood. In each tunnel thimble-sliapcd cells are made of pieces of rose- leaves and are filled with pollen and honey. One egg is laid in each cell, which is then sealed with circular pieces of rose-leaf. The cells of the leaf-cutter bees are also not infrccpiently placed in cracks of hou.ses or trees, imder stones and boards in deserted earthworm holes, or in the holes of cariienter bees (q.v,), in auger-holes, or in lead jupe; and they have even been found in the nozzle of an old disused pump. See Plate of Bees. LEAP-FROG. One of the small American tro]iical frogs of the family Cystignathi<he and genus llylodes. of which alwiut iiO species are known. All are less than two inches long, are a-, a rule brightly colored and changeable, and have the general habits of tree-frogs (q.v.). The fingers as well as the toes are provided with disks, enabling the animals to cling to the leaves of plants and trees, as they habitually do. The males have vocal sacs and make chirping sounds. A remarkable species is the coqui ( IJi/lorlcs Mar- tiniensi.i) . of Porto Rico. Haiti, and the . tilles, whose young luidcrgo their whole metamorphosis before emerging from the protection of the egg. The female glues aliout 20 large eggs enveloped in a foamy mass up<jn a broad leaf, or in the axil of a flag, and then seems to remain near by awaiting developments. Each embrj'o (tadpole) grows to maturity within its egg, develo])ing neither gills nor gill-o))enings, but apparently breathing through the liighly vascularized tail. At last the food-yolk and liquids of the egg are exhausted, the tail is rapidly absorbed, and a minute but perfectly forniecl frog breaks the shell an<l hops away. A frog of the Solomon Islands has a similar method of development within the egg. See Hylodes. LEAF-HOPPER. A bug of the family Jii^- sidic. The leaf-hoppers are among the most abundant of the bugs, and comprise a great com- plexity of forms. By most modern writers the group is considered of superfamily rank, and is known as .Jassoidea. All are small insects. One species (Cicaclula exitiosa) infests winter wheat. The grapevine leaf-hopper (Enjthroncura vitix) often occurs in great numbers on the vine, and is very injirious to it. It is known to grajie- growers as "the thrips' or 'grapevine thrips,' a mislea<ling name. ( See Tiimi'S. ) Scores of spe- cies feed ujion grasses and bring about a veiy extensive although probably unnoticed damagi' to the grazing ranges of the West. LEAF-INSECT, or Walking-Leap. One of a very remarkal)le group of insects of the ortliop- terous family Phasmida", natives of tropical coun- tries, chiefly of the East Indian region, having wings extremely like leaves, not only in color, but in the way they are ribbed and veined. The joints of the legs are also extended in a leaf-like manner. So close is the resemblance that the na-
