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194 COLLEGE ENTOMOLOGY
As they cannot fly, they are distributed largely by personal contact or from the
nests and roosts to the young and to other species. As they are able to live but a
short time away from a warm,blooded host. it is not clear how some species
have become so widely distributed among the different hosts.
The elongated eggs or nits are glued singly on the hairs or feathers of the
host, and the young appear much the same as the adults. They breed under
palpus,--····,'_,· "" ....... _ .. .
FIG. 70. Large poultry louse, Menopon stramineum Nit2;sch. A, dorsal aspect;
B, ventral aspect.
very favorable conditions, having a fairly uniform heat from the body of the
host to make them comfortable under most climatic conditions. The broods
are overlapping, and there are several to many generations a year.
The chief damage to the host is through constant irritation. The species
affecting sheep and goats are responsible for a considerable financial loss,
since they partially cut or weaken fiber of the wool, thus reducing its length and
quality.
According to Tillyard, no fossils of this order have yet been discovered.
The members of the order MALLOPHAGA have a very wide distribution
because of the great range of many of the hosts, especially birds, upon which
they live. Beier (1!}36) lists 2,000 described species, there being no less than
500 species in Germany alone. Muesebeck (1937) estimates that there are
2.500 described species.