352 AMERICAN MICRO- LEPIDOPTERA. 



at the anterior end and by two diverging threads at the posterior 

 end. When the imago emerges the pupa case is thrust through the 

 upper epidermis. 



Cremastobombycia ambrosiella Chambers. 



Plate XXIV, Fig. 18. 

 Lithocolletis ambrosiella Chambers, Can. Ent., iii, 127, 1871. Cin. Quart. Jn. Sci., 



ii, 100, 1875. Frey and Boll, Stett. ent. Zeit., xxxvii, 221, 1876 ; xxxix, 



267, 1878. Walsingham, Ins. Life, ii, 54, 1889. Dyar, Bull. 52, U. S. 



Nat. Mus., 1902, No. 6321. 

 Syn. amcena Frey and Boll, Stett. ent. Zeit., xxxix, 269, 1878. Dyar, Bull. 52, U. 



S. Nat. Mus., 1902, No. 6285. 



Antennge gray, annulate with dark brown. Face and palpi whitish, sometimes 

 with a deep blue-gray metallic lustre. 



Thorax and forewings reddish saffron. A fine white line on each side of the 

 thorax is continuous with a short basal streak broadening toward the end, where 

 it is faintly dark margined. At the basal fourth is an oblique white costal 

 streak, dark margined externally. Very rarely there is a minute white spot on 

 the dorsal margin, with a few black scales behind it. About the middle is a 

 white fascia, sometimes angulated, margined with black behind and with a 

 slightly darker shade before. At the beginning of the cilia there is a white cos- 

 tal streak and a slightly oblique dorsal one opposite, both dark margined behind 

 and faintly so before. Just before the apex is a curved white streak, sometimes 

 attaining the dorsal margin, with a few dark scales behind it in the apex of the 

 wing. Cilia of the wing color, grayish toward thetornus. Expanse 5.5-6.5 mm. 

 Hindwings gray, cilia with a fulvous tinge. Abdomen gray, somewhat metal- 

 lic, tuft tinged with ocherous. Legs fuscous, tarsi white, broadly annulate with 

 black. 



Widely distributed in the east, also occurring as far south and 

 west as Texas (Boll). The larvae mine the leaves of Ambrosia trifida 

 L. and Ambrosia artemisiaefolia (L.) Britton, and of Verbesina alter- 

 nifolia (L.) Britton (Actinomeris squarrosa Nutt.). The mine is very 

 small, placed upon the under suface, and is not visisble on the upper- 

 side as an inflated swelling, as is that of ignota. The dense white 

 fusiform cocoon, suspended hammock-like in the mine, has a smooth 

 surface, lacking entirely the longitudinal ridges characteristic of that 

 of ignota. 



Easily distinguished from ignota in its early stages, the imagoes 

 may be distinguished from that species by the broad white basal 

 streak, which in the form described by Frey and Boll as amcena, 

 attains the dorsal margin ; by the absence of the brilliant silvery 

 lustre of the white markings. Amcena lacks the dark margins pres- 

 ent on the type of ambrosiella. Bred specimens show great varia- 

 tion in the distinctness of these margins. 



