The Life-History and Anatomy of Moths 
The fore and hind wings in some of the primitive forms are 
not connected with each other in the operation of flight. In the 
Hepialidce there is a lobe near the base of the primaries which is 
Fig. 12. —Diagram of Wings of a Moth. (After Hampson’s “Moths of 
India,” Vol. I., with modifications.) 
A. Fore Wing. B. Hind Wing. 
c.m. Costal margin. 
o.m. Outer margin. 
i.m. Inner margin. 
a.a. Apex. 
■i. a. Inner angle. 
c. Discoidal cell. 
d. Discocellulars. 
ar. Areole. 
f. Frenulum. 
c.n. Costal nervure, vein 12 of fore wing, 
8 of hind wing. 
s.n. Subcostal nervure. 
m.n. Median nervure. 
1 a, b, c. Three branches of internal nervure. 
2, 3,4. Three branches of median nervure. 
5. Lower radial. 
6. Upper radial. 
7,8,9,10,11. Five subcostal branches of fore wing. 
7. Subcostal nervure of hind wing. 
known as the jugum , but it does not appear to serve the practical 
functions of a yoke. This is illustrated in Figure 13. In the vast 
majority of cases a connection between the fore and hind wings 
is made by means of the frenulum on the hind wing, which hooks 
into the retinaculum upon the fore wing, as illustrated in Figure 14. 
The form of the frenulum is of use in determining the sex of 
specimens, as in the case of the males it consists of a single 
curved, hook-like projection, whereas in the case of the females 
it is split up into a number of bristles. However, in some 
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