I. TRAGA.RDH, LEPIDOPTEROUS LEAF-MINERS. 



27 



it was only to be expected that those of the tissue-feeders 

 should prove to be the less modified in this respect. 



In Eriocrania (fig. 38) the number of teeth is less than 

 usual, but the remaining three are larger than usual, and the 

 mandibles are dorso-ventrally compressed. The fringes of the 

 median edge have been discussed on pag. 24. 



In Tischeria (fig. 39) they are of nearly the same type, 

 but the ventral tooth is comparatively larger, and placed 

 nearer the middle. 



4A 



Fig. 41. Mandible of Cemiostoma scitella. ventral aspect. X 465. 

 Fig. 42. Mandible and labrum of Ornix guttea, dorsal aspect. X 465. 

 Fig. 43. Mandible of LithocoLletis sp., ventral aspect. X 348. 

 Fig. 44. Labrum, mandibles and top of hypopharynx of Gracilaria 

 syringella, 1st instar, dorsal aspect. X 609. 



In Nepticida (fig. 40) the ventral tooth is small, but placed 

 on a level with the one next to it; the other three are 

 rounded at the top and diminish gradually towards the dorsal 

 edge so that the tips are on a line with one another. 



The most remarkable feature is, however, that the man- 

 dibles are ho ri zon tal and that the three teeth mentioned 

 above are on the same level, whereas the 4th is placed exactly 

 below the external one. 



