LIBRARY

HEMIPTERA 337
and reaches the greatest development in the north temperate zone. The
members are singularly scarce in the tropics although many species have been
described from southern Asia, particularly from Formosa and Java. There
yet remains much to be done in collecting and studying them in other equatorial
regions.
The family is composed of a considerable number of subfamilies, tribes, and
subtribes, and no less than 150 genera and nearly 2,000 species. Lack of space
prevents the inclusion of more than a few representative species.
Members of the genus Cinara Curtis are large brownish or greenish hairy
species which generally feed upon coniferous trees. The important species
occurring in both Europe and North America are C. pinicala (Kalt.) on Pinus
and Larix; C. pice;e (Walker) ( == vanduzei Swain) on Picea and Abies; C.juniperi
(DeGeer) on Juniperus; and C. tujafilina (Del Guercio) on Thuja, Cupressus,
and Retinispara.
Lachniella castata (Zetterstedt) is smaller but otherwise similar to species of
Cinara. It is common in Europe on Pinus, Picea, and Abies.
The large willow aphid, Pierochlarus salignus (Gmelin), is one of the largest
species, attaining a length of 5 mm. It is brown with a large, conspicuous
triangular tubercle on the middle dorsum just in front of the short cornicies.
It is common on willow, rare on poplars, and occasionally on apple, apricot.
and peach and occurs throughout parts of Europe, Africa. Asia, and North
America.
Stamaphis quercus (Linn.), infesting oaks, maples, poplars, and willows in
Europe, is remarkable for the very long rostrum which may be nearly twice
the length of the body.
Euceraphis betul;e (Linn.) and Calaphis betuhecalens (Kalt.) occur on birch
in Europe and North America. Phyllaphis jagi (Linn.) is a white woolly
species on beech with the same wide range.
Drepanosiphum platanoides (Schrank), a large green species, is common
on maple in Europe and North America. It is very active on bright, hot days.
Species of the genus Myzocallis Passerini are mostly small and yellow with
or without clouded wings and dorsal abdominal tubercles. M. ononidis (Kalt.)
(== trifolii Monell) occurs on Onanis and Trifolium in Europe, northern Asia,
and North America. M. tilia! (Linn.) occurs on linden wherever grown in
Europe, Asia, and North America. M. coryli (Goeze) infests Corylus, Carpinus,
Quercus and Primula in Europe and Corylus in North America. M. castanicala
Baker feeds on Carya, Castanea, Quercus, and related plants in Europe, Asia.
NQrth America, and New Zealand.
Three common species of Peripltyllus Van der Hoven: P. aceris (Linn.),
P. negundinis (Thomas), and P. testUdinatus (Thornton) are dark-green or
blackish species infesting maples. They occur in Europe and North America,
excepting P. negundinis (Thomas) which occurs only in North America.
Laing, reported by Tillyard from New Zealand, was never published unless the description bY'
the latter is sufficient to establish the species. Many species have been introduced into both
areas through commerce.