HEMIPTEHRA-HETEROPTERA. 
INTRODUCTION. 
Tue Hemiprera, or bugs, may be known by their haustel- 
late mouths, incomplete metamorphoses, and four wings, 
In the Heteroptera the anterior pair of wings, or elytra, 
are of a more or less coriaceous texture, except towards the 
apex, which is generally membranous, the posterior pair are 
membranous and fold up under the elytra; both elytra and 
posterior wings are often undeveloped. The pronotum in 
the Heteroptera is very large, and produced backwards as 
in the Coleoptera, as is also the scutellum, except in a 
few genera; the membranous apices of the elytra in the 
developed forms overlap, so that the suture is not straight 
as in the Coleoptera. Developed and undeveloped speci- 
mens of the same species often occur together, and in 
some the developed form is exceedingly scarce; in the 
undeveloped forms the elytra are generally shortened, 
and the membrane either curtailed or entirely absent, 
and the posterior wings abortive; there is also in some 
genera an intermediate or brachypterous condition, in 
which the posterior wings are shortened and the membrane 
comparatively slightly modified; in the brachypterous and 
apterous forms the pronotum is less developed poste- 
riorly, and this modification has been the canse of the erec- 
tion of many new species which are now correctly referred 
to their developed forms. In variability of shape the 
B 
