198 
THE STUDY OF INSECTS. 
the insect from which the wings were taken should be kept with the 
slide. It is our practice to remove always the wings from the right 
side, and then to mount the slide in the collection at the right of the 
insect from which the wings were taken. Uniformity in this respect 
adds greatly to the appearance of the collection. 
ni * - The student should 
study his larger speci- 
mens first, leaving the 
5 smaller ones till he has 
acquired skill in this 
work. 
There are a few spe¬ 
cial terms used in de¬ 
scribing the wings of 
the Lepidoptera which 
should be learned:— 
Frenulum .—In most 
moths there is a strong 
spine or a bunch of 
bristles borne by the 
hind wing at the hume¬ 
ral angle (Fig. 237, /); 
Fig. 237-—'Wings of Thyridopteryx ephetneraformis. this is the frenulum. 
Its use is to insure the acting together of the two wings of one 
side. Except in the Microlepidoptera the frenulum of the male 
consists of a single strong spine; 
that of the female of two or 
more bristles.* 
Jugum .—In one suborder, 
including only a few rare moths, 
there exists, instead of a fren- 
;ulum, a lobe borne near the 
base of the inner margin of the 
fore wing (Fig. 238, j ); this 
is the jugum. See sub-order 
Jugatae. 
Discal Cell .—Near the cen¬ 
tre of the basal part of the 
wing there is a large cell lying 
Vila VII, 
Fig. 238.—Wings of Hcpialusgracilis. 
between veins III and VII (Fig. 239, d.c .); this is the discal cell. 
In the more generalized Lepidoptera this cell is divided into two 
parts by the base of vein V (Fig. 239, hind wing); in such cases the 
