2l8 DAVENPORT ACADEMY OF SCIENCES. 



even three of the transverse veins, (when the upper surface 

 becomes somewhat uneven) but never, as far as observed, across 

 the midrib. The horizontal diameter ranges between 3-1 1""- 

 (those growing singly being usually much the largest) and 

 between 1.6-3.4™"- in height. The form is quite flat or but 

 slightly convex above, with the circumference usually sharply 

 defined and sunken below the plane of the leaf, which forms 

 around it a somewhat elevated and quite sharp edge or rim. 

 The disk may be raised button-like above the plane of the leaf. 

 Sometimes the upper surface is slightly uneven or concave; or 

 there may be a slightly convex, central elevation, with a dimpled 

 depression on one side of it. Beneath it is much more prominent 

 and convex, resembling somewhat that of c. -septum, except 

 that its nipple is extremely short and conical, with the orifice 

 round and completely closed in the younger ones, with indica- 

 tions that it will split when mature into 5-8 short bracts, which 

 are closely covered at the tip and inner side with minute, white, 

 silken hairs. The surface above is perfectly smooth, whilst the 

 under side is sparsely beset with short, pale yellowish, radiating 

 hairs and yellow papillae which characterize the under side of 

 the leaves. 



It is seen to be slightly transparent, if held between the light, 

 especially around its margin. Its walls are rather thick and 

 hard, especially at the base. The color above and beneath is of 

 a somewhat paler green than the surrounding surface of the leaf, 

 occasionally faintly tinted with red at the centre and polished 

 above. 



Each gall contains, by the middle of May, besides the single 

 stem-mother, large numbers of eggs, larvae and young pupae, 

 covering closely its inner walls, each with the end of the body 

 directed toward the centre, as if they were standing on their 

 heads. Some individuals acquire wings by about the 20th, while 

 the majority do not reach this condition till the end of the month 

 or the first week in June. 



Stem -MOTHER. — I,ength when fully developed about i™™-; 

 greatest diameter about o.s""'- Elongate-pyriform, the older, or 

 those which are nearly empty of eggs, are more or less broadly 

 ovoid, ce-cS"""- in length and 0.4-0.7"""- in diameter. Color 



