594 



AN INTRODUCTION TO ENTOMOLOGY 



In this family the mandibles of the adult are vestigial; the maxillee 

 are formed for sucking, each maxilla forming half of a long sucking- 

 tube, as in higher Lepidoptera. The females lack a bursa copulatrix 

 but have a piercing ovipositor. An easily observed recognition 

 character is the fact that the subcosta of the fore wings is forked near 

 its apex (Fig. 720). The jugal lobe of the fore wing extends back 

 above the base of the hind wing and is clasped over an elevated part 

 of the hind wing, thus being of the type described as a fibula (see 

 page 62). 



Our best-known representative of this family is Mnemonica 

 auricyanea. The structure and transformations of this species have 



Sc, Sc, Ri 



2d A 1st A 



Fig. 720. — Wings of Mnemonica. 



been described by Busck and Boving ('14). The adult has a wing- 

 expanse of from 1 2 to 1 4 mm. The larva mines in the leaves of chestnut, 

 oak, and chinquapin in early spring, making a large, bulgy blotch 

 mine; it completes its growth within a week or ten days, and goes 

 into the ground to transform, where it spins a tough cocoon; the 

 change to pupa takes place in the following winter; the adult emerges 

 in April. The pupa has long, arm-like toothed mandibles, with which 

 it cuts the tough cocoon and with which it digs its way up to the 

 surface of the ground. This species is found in the East. 



Family HEPIALID^ 

 The Swifts or the MacrojugatCB 

 The members of this family are of medium or large size. 



