4 INTRODUCTION. 



(5) the 5-jointed tarsus bearing a pair of ungues and the pulvillus. 

 The fore tibiae bear on their inner side a process which is usually 

 small, but large and "arising from the fernoro-tibial joint in many 

 Psychids and a few other forms. The mid tibia? usually have a 

 terminal pair of spurs, the hind tibia? medial and terminal pairs, 

 the inner spur of each pair being often much longer than the outer 

 spur. The spurs are as a rule least developed in the higher groups 

 of moths, more developed in the lower Noctuidce and Geometridce, 

 longer still in the Microlepidoptera (Tinceidce, Pyralidce, &c), and 

 reaching the extreme of development in the Pterophoridce. The 

 legs often bear tufts of scales or hairs, developed as scent or sensory 

 organs, and the hind legs are often extremely aborted and modified 

 as sensory organs, especially in the Hepialidce and in the subfamily 

 Acidaliince of the Geometridce. 



The wings consist of membrane more or less covered with scales 

 or hairs, which have their bases inserted in series of pits, and over- 

 lap one another like tiles. The membrane is traversed by systems 



B — 



Fig. 4. — A. Fore wing ; B. Hind wing. 



cm. Costal margin. era. Costal nervure, vein ] 2 of fore wing, 8 of hind wing. 



o.m. Outer margin. s.ra. Subcostal nervure. 



i.m. Inner margin. m.n. Median nervure. 



a.a. Apex. 1 a, b, c. Three branches of internal nervure. 



o.a. Outer angle. 2, 3, 4. Three branches of median nervure. 



c. Discoidal cell. 5. Lower radial. 



d. Discocellulars. 6. Upper radial. 



7, 8, 9, 10, 11. Five subcostal branches of fore wing. 

 7. Subcostal nervure of hind wing. 



of veins, which are. tubular structures containing blood-vessels, 

 nerves, and trachea?. 



The fore wing typically has 12 veins — the internal nervure 

 with from one to three branches (1 a, b, c), 1 a generally forming a 



