410 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.51. 



by 0.26 mm., but varying considerably. Margin with minute irreg- 

 ular incisions and devoid of all hairs or bristles excepting a cephalo- 

 lateral pair, one large caudal pair, and a smaller caudo-lateral pair. 

 There is a slight constriction in the region corresponding to the tra- 

 cheal pores of the pupa case, and sometimes there are a number of 

 regular tootlilike projections therein. The vasiform orifice is rounded 

 cordate, the operculum similar in shape, with the exception that the 

 lateral margins are somewhat constricted. The liugula is not visible. 

 The dorsum is covered with numerous granular markings. 



TMrd instar. — Color similar to that of the second instar; shape 

 oval; size 0.59 by 0.432 mm. Margin with minute indentations and 

 with three pairs of bristle-like hairs similar to those of the second 

 instar. In this instar the three tracheal folds are evident and are 

 marked within with a large number of minute circular transparent 

 areas similar to those present in the folds of the pupa case. The 

 vasiform orifice is similar in shape to that of the second instar. 



Pupa case. — On the leaf the pupa cases are yellowish in color, 

 sometimes slightly brownish. They are devoid of either dorsal or 

 lateral secretion, are lighter toward the margin than on the median 

 dorsal area, and the entire case when in certain lights often shows 

 very beautiful hues and iridescent colors. The cases are placed upon 

 the leaf without any definite arrangement as to the veins, but are 

 nearly always situated on the under surface. There is a very nar- 

 row, acute, dorsal keel extending down the middle of the thorax 

 and joining the transverse suture, which divides it from the abdomen. 

 On the central dorsal area, that part immediately above the body 

 of the developing adult, the segments of the body are distinctly 

 marked, somewhat rounded, and the entire surface perfectly smooth 

 and highly polished. The lateral area of the dorsal disk, however, 

 is very minutely and irregularly striate, in some cases giving almost 

 the appearance of minute punctures. The thoracic tracheal breath- 

 ing folds are raised above the surrounding area, and the operculum 

 and caudal tracheal areas are usually slightly elevated. On the 

 submarginal area the striations which show considerable irregularity 

 on the dorsal area become more even, extending in from the margin. 

 The marginal area is somewhat rounded, being curved downward 

 slightly to meet the margin, which is considerably nearer the leaf 

 than the highest point of the case. In some specimens the median 

 area of the case collapses as the insect within dies, owing to drying 

 upon the leaf. These are generally paler in color than those which 

 have not shrunken. 



Under the microscope (pi. 64, fig. 1) the color is pale yellowish, 

 almost transparent on the margins and often somewhat darker on the 

 median area, owing to the color of the viscera. In shape the case 

 is subeUiptical, tending toward oval in some specimens, and often 



