348 AMERICAN MICRO-LEPIDOPTERA. 



"The larva mines the upper surface of the leaves of oaks in September, and 

 doubtless also in tbe summer months. The mine is a linear tract, sometimes 

 curved or wavy, gradually increasing in breadth from the beginning to the end, 

 or, as the larva increases in length, with the frass deposited on each side of the 

 tract, and marking its outline by two black lines. The position of the larva 

 within the mine is likewise a peculiar one, as it is always placed transversely to 

 its course, and hence the deposition of the frass on the sides, and the gradual 

 increase in breadth, as the larva grows in length. Its head is blackish-brown ; 

 the body pale greenish, with pale brown dorsal maculae, darker on their edges. 

 It undergoes transformation in the end of the mine, preparing a circular cell or 

 slightly silk-lined cavity, and leaves the last larval cast outside of it. The fall 

 brood of larvse become imagoes about the middle of May." 



The above is Clemens' complete description of the species. 



The very characteristic mine can- 

 not be mistaken for that of any other 

 species. The mine is often branched, 

 the larva returning toward the begin- 

 ning of the mine, and starting out 

 anew in another direction. 



In the apex of the wing, there is 

 sometimes a minute white spot, with a 



Mine of L. tubiferella. 111 i i i i - mi i 



few black scales behind it. I he alar 

 expanse is 8 mm. 



PORPHYROSELA,* new subgenus. 



Porphyrosela differs from the typical Lithocolletis in the follow- 

 ing characteristics : forewings somewhat more acuminate, vein 11 of 

 the forewings absent (Plate XX, Fig. 8) ; basal joint of the antennae 

 without a pecten ; hind tibise without hairs. 



The subgenus is represented only by the following species : 



Porphyrosela desmodiella Clemens. 



Plate XXIV, Figs. 14, 15. 



Lithocolletis desmodiella Clemens, Proc. Acad. Nat. Sci. Phil., 220, 1859. Tin. No. 

 Am., 65, 68, 1872. Chambers, Can. Ent., iii, 127, 162, 1871. Jn. Cin. 

 Soc. Nat. Hist., ii, 189, 1879. Frey and Boll, Stett. ent. Zeit., xxxvii, 

 227, 1876. Walsingham, Trans. Am. Ent. Soc., x, 202, 1882. Busck, 

 Proc. Ent. Soc. Wash., v, 187, 1903. Dyar, Bull. 52, U. S. Nat. Mus., 

 1902, No. 6303. 

 Syn. gregariella Murtfeldt, Can. Ent., xiii, 245, 1881 ; xv, 139, 1883. Walsingham, 



Proc. Zool. Soc. Lond., 146, 1897. 



"Antennae dark brown, tipped with a silvery hue. Front whitish, with a ruby 

 colored lustre; frontal tuft dark brown. Thorax with a splendent ruby hue. 



* From ir6p<t>vpo<s, purple; and creAas, signifying sheen. 



