LEPIDOPTERA 613 



Family PSYCHID^ 

 The Bag-Worm Moths 



The bag-worm moths are so called on account of the silken sacs 

 made by the larvae, in which they live and in which they change to 

 pupse. In our more conspicuous and best-known species 

 the sac is covered either with little twigs (Fig. 748) or, 

 in the case of a species that feeds on cedar or arbor-vitae, 

 with bits of leaves of these plants. When the larva is 

 full-grown it fastens its sac to a twig or other object 

 and transforms within it. 



In the adult state the two sexes differ greatly. The 

 female is wingless, and in some genera the eyes, an- 

 tennee, mouth-parts, and legs are vestigial or wanting, 

 the body being quite maggot-like. At the caudal end , 

 of the body there is a tuft of hair-like scales which are 

 mixed with the eggs. In most species the female does 

 not leave the sac before oviposition but deposits her 

 eggs within it. 



The male moths are winged; they are small or of Fig- 748. — ^Bag 

 moderate size. The wings are thinly scaled and in oi Otkettcus 

 some species nearly naked; when clothed with scales " ^^' 

 they are usually of a smoky color without markings. The venation 



of the wings varies 

 I? 3^ J^ greatly within the 



'^'^"^'^^^ ~ family. Figure 749 

 represents the vena- 

 tion of our most com- 

 mon species. 



Only about twenty 

 species are known from 

 our fauna, of which the 

 following are most 

 likely to be obsen^ed. 

 Abbot's bag-worm, 

 Otkettcus abboti. — This 

 species occurs in the 

 more southern part of 

 our country. The lar- 

 va makes a bag with 

 sticks attached to it 

 crosswise (Fig. 748). 

 The adult male is 

 sable brown, with a 

 vitreous bar at the ex- 

 tremity of the discal 

 cell of the fore wings ; the narrow external edging of the wings is pale; 

 the expanse of the wings is 33 mm. 



Fig. 749. — Wings of Thyridopteryx ephemercB- 

 formis. 



