EXTERNAL ANATOMY OF INSECTS. 613 
several of them, a part which I suspect to be analogous 
to that above described in Coleoptera, supposed to re- 
present the phialum of wings. I shall first speak of the 
areas. In some apterous species related to the bed-bug, 
Lygeus brevicoilis®, &c., there is no trace of the usual 
areas, and the membrana is a very narrow strip; in ZL. 
apterus the former are very faintly traced out, but they 
are present in all those that are furnished with wings ; 
whence we may conjecture that they are of the same im- 
portance in flight with the folds observable in those or- 
gans®. The three basal areas may be said most com- 
monly to present three isosceles triangles, the Costal one 
being narrow and curvilinear’, the Intermediate the 
most ample‘, and the Anal one the narrowest and 
shortest £, with its vertex towards the apex of the He- 
melytrum, while in the two former it is at its base. In 
Rhinuchus compressipes the Anal Area is cultriform ; 
and in most of the Hydrocorise it has an angle in the 
middle of its posterior margin. The proportion that 
the membrana or apical area bears to the rest of the 
wing varies in the different tribes. In some, as before 
stated, it is obsolete, in others nearly so; in the majority, 
perhaps, it occupies about a third of the hemelytrum ; in 
R.compressipes, Lygeus cruciatus, &c., fullhalf ; in Alydus 
calcaratus, two-thirds; in Reduvius, nearly three-quarters: , 
* See above, p. 598. : 
> My insect, which nearly resembles the Coleopterous genus Cery- 
Jon Latr., agrees with Latreille’s description in all respects, except 
that it cannot be said to be membrana nulla apical. 
© Chabrier Analyse, &c. 24. 4 Prate X. Fic. 3. b. 
* Ibid. c*. Pv ibids d. 
@ Prare XXVIII. Fie. 23. f”" is the corium and g” the membrana 
of a species of Reduvius. 
