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. 



The student should 

 study his larger speci- 

 mens first, leaving the 

 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, /); 



FlG. 237. Wings of Thyridopteryx ephemerceformis. 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. 



Jitgum. In one suborder, 

 including only a few rare moths, j 

 there exists, instead of a fren- 

 julum, a lobe borne near the 

 base of the inner margin of the 

 fore wing (Fig. 238,7); 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 



VII2 VII, 



FIG. 238. Wings of Hepialus gracilis. 



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 



