LIBRARY

92 COLLEGE ENTOMOLOGY
eggs may be deposited from two to four times a year. The young outwardly
differ from the adults only by the smaller size, variation in color, and absence
of wings although many forms are wingless throughout their entire existence.
After five to eight ecdyses the adult stage is reached. There is usually only one
generation a year, but certain tropical species have two. Reasons for migrations
are not clearly known but it appears that only certain types of individuals
within a species known as the "swarming phase" make these great flights while
those which do not migrate are called the "solitary phase." The most important
migratory locusts are:
EURASIA, NORTHERN AFRICA, OCEANIA
The desert locust, 5'chistocerca gregaria ForsldU (5'. peregrina Olivier, S. tatarica
Linnreus), has a yellow, nonmigratory phase and a pinkish, migratory phase,
both marked with small dusky patches on the tegmina. It is 2 in. or over in
length. It breeds in sand hills with sparse vegetation and is believed to be the
locust oiten mentioned in ancient writings as causing the plagues of Egypt,
northern Africa, Arabia, Persia, Afghanistan, northern India, and the islands
of the Mediterranean. It flies long distances and has been found 1,200 miles at
sea. In 1881 in Cyprus 1,600,000,000 egg cases, or 1,300 tons of eggs, were destroyed,
and in 1883 it was estimated that nearly four times as many eggs were
deposited in the soil of the island. In the Sudan in 1930, 1,100 tons of poison
baits were used to stay its ravages.
The migratory locust, Locusta migratoria Linmeus (L. migratorioides Reiche
and Fairmaire, L. danica Linmeus), is yellowish or grayish-green and about
2 in. long. It occurs in most of Europe, Africa, Asia, Oceania, northern Australia,
New Zealand, and Madagascar. It breeds in dry grassy places next to
jungles and swamps, in burnt-off places, and in other areas of sparse vegetation
and is often a very serious pest. The Bombay locust, Cyrtacanthacris succincta
(Linnreus) (Acrydium), is a reddish species similar to the migratory locust which
often occurs in immense swarms in India.
The Moroccan locust, Dociostaurus moroccanus Thunberg, is pale grayishbrown
with black spots and averages about 1 in. in length. It occurs throughout
the Mediterranean region and ranges east into northern Persia and Turkestan.
It breeds in hilly or mountainous regions.
The Italian locust, Calliptamus italicus (Linnreus), is dark brown, yellowishbrown,
or grayish, often with small gray or brown spots on the tegmina, and is
about 1 in. long. It breeds extensively in sage-brush steppes and in the loose
dry soils of areas of sparse vegetation and occurs within about the same range
as the Moroccan locust. .
SOUTH AFRICA
The brown locust, Locustana pardalina (Walker), is yellowish-gray with
small brownish spots on the tegmina, and nearly 2 in. long. It breeds in the
desert grass lands of interior South Africa and may migrate to the coasts.
There may be two or more generations a year.