LIBRARY

346 COLLEGE ENTOMOLOGY
Members of the unique genus Margarodes live on the roots of plants and
have fossorial forelegs for digging in the soil. The females are enclosed in wax
cysts formed of overlapping plates which have a metallic gold- or bronze-like
luster and are gathered and worn like beads by the natives wherever the insects
occur. They are also commonly referred to as ground pearls. The females under
unfavorable conditions may remain quiescent in these cysts for 1 or more years.
They then emerge after rains, become active, and resemble mealybugs in appearance.
Species are to be found mostly in the tropical and temperate regions
in all parts of the world, but their subterranean habits make them difficult to
collect except in a few localities. Several species are known to feed upon the
roots of the grape, and some occur in termites' and ants' nests. Certain species
are odorous. M. capensis Giard, with cysts 7 rom. in diameter, is a well
known species in South Africa. M. trimeni Giard, common in termite nests of
South Africa, is gathered and strung as beads by the natives and worn or sold
as "anis' eggs" at Capetown (Brain, 1929). M. polonicus (Linn.), the "scarlet
grain" of Poland and eastern Europe, was early used as a source of dye and was
an article of trade of some importance. It lives on the roots of Scleranthus annuus.
The North American species include M. hiemalis Cockerell from New
Mexico and M. formicarum Ckll. and M. n'Zeyi Giard from the West Indies and
Florida. Ferris (1919) notes an interesting case of M. vitium Giard, a pest on
the roots of grapes in Chile and Venezuela. Specimens in cysts were collected in
Chile in 1899 or 1900; and in 1917, when several of the dry cysts in the collection
were opened, one female was believed to be still alive after 17 years
without food!
Family ORTHEZIIDlE (Green 1896 as ORTHEZITES), Enderlein 1920.
(Or'thez-i'i-dre; named after the Abbe Orthez or D'orthes who discovered
it in France). Ensign Cocdds.
The members of this small family are largely Nearctic, Neotropical, and
Pahearctic. Two species, Orihezia cataphracta (Shaw), a species common to
Europe and Siberia, and O. occidentalis Douglas, an inhabitant of western North
America, live within the north polar region, the former in Greenland and the
latter in Alaska, where they subsist on the roots of plants. The family is not
represented in the Ethiopian, Oriental, or Australian regions. The females are
covered with hard white waxy plates and often carry a large wax egg sac or
marsupium at the posterior end. The bodies are elongate-oval, convex, distinctly
segmented; one pair of ocellanre on tubercles; prominent four- to ninesegmented
antennre; two-segmented rostrum; normal legs; thoracic and abdominal
spiracles; and anal ring bearing pores and six anal ring setre. The
males usually have well-developed compound eyes; some with three ocelli;
setiform nine-segmented antenme; sheath of penis divided; small style. The
one important species is Orthezia ins ignis Douglas, a tropical form commonly
known as the greenhouse orthezia because of its wide dissemination on ornamental
plants in greenhouses throughout the world. O. urticce (Linn.), the type
species, is common on many hosts in Europe and Asia. .