I. TRÄGARDH, J.EPIDOPTEROUS LEAF-MINERS. 



43 



The line of demarcation between the hypopharynx and 

 the mentum is not so distinct (compare figs. 59, 60 and 61), 

 nor is the structure so large as in Gracilaria. 



In Lithocolletis (figs. 62 & 63), we find that the cardo of 

 the maxillae is well developed, and projects at a sharp angle 

 above the level of the capsule. Stipes is "well developed, and 

 has the usual pair of small hairs. All that remains of the 

 palpiger, the palpus and lobus externus and internus, are two 

 pairs of hairs, which, however, are placed on the do r sal 

 si de of the labium, as is shown in fig. 63, which represents 

 the labium dissected and viewed from the inner, dorsal side. 



64 



Phyllocnistis suffusellu. 



Fig. 64. Right half of labium and hypopharynx with lateral margin 

 of mandible, ventral aspect. X 386- 



It appears that this is achieved in such a way that the labium 

 has increased laterally, so as to completely cover the palpiger 

 which became atrophied, the oniy structure which bears 

 witness of its previous existence being the two hairs and a 

 pair of longitudinal thickenings of the cuticle. The hypo- 

 pharynx and the mentum have increased still more in size, 

 and are distinctly separated, as in Gracilaria, but in one 

 species there is a pair of lobes, medially, at the anterior 

 margin of the mentum, the interpretation of which is uncertain 

 (basal joint of labial palpi?). Tbe hypopharynx is densely 

 hairy and the lateral angles of the mentum are hook-shaped 

 and curved upvvard, so as to reach the level of the labrum. 



