622 EXTERNAL ANATOMY OF INSECTS. 
this last Area is marked out from the Intermediate by a 
marginal notch, which is not present in Phasma, but is 
found in both sections of the Hemiptera. In Locusta 
the notch is between the Costal and Intermediate Areas: 
in Phasma the nervures of the Intermediate Area are 
branches of the externo-medial, while those of the Anal, 
as they do in all the Orthoptera, diverge from the base 
of the wing: in many, as in Prerophylla, the part of the 
wing lately alluded to, that is longer than the fegmen, 
and of the same substance, points out the limit of the 
Costal Area; and in others this part terminates in a 
segment of a circle and is differently reticulated at the 
apex from the Intermediate : in the Homopterous Hemz- 
ptera and the Libellulina, in which the areas at first seem 
indistinct, they may generally be easily traced by follow- 
ing them from the axes. The separation of the Costal 
from the Intermediate in the remaining Orders seems 
less easy on account of the branching of the nervures ; 
in the rest of the Neuroptera and the Lepidoptera, if the 
posterior branches of the postcostal nervure are not in- 
cluded, you will have a narrow Postcostal Area, which in 
most cases forms an angle, more or less prominent, in 
Corydalis almost a right angle, with the Intermediate: 
in Hemerobius and affinities this part is distinguished by 
areolets formed by ¢ransverse nervures, while those of 
the rest of the wing are longitudinal*; but if the posterior 
branches are included, the Costal Area will be more 
ample: a similar observation applies to the Hymenoptera 
and. Diptera ; in these, in all cases, the areolets adjoining 
the anterior margin, which follow the stigma, should be 
regarded as belonging to the Area in question®. In 
@ Prate X. Fic. 7. 2h. 7. ke’. > Thid. Fic. 8. 9. 12. a*. 
