2 26 DAVENPORT ACADEMY OF SCIENCES. 



here considered is identical with that described by him under the 

 above name. 



The first notes upon the species were made in 1872 when it was 

 found in Missouri on the leaves of the Bitter-nut Hickory, 

 {Hicoria amara'). This is one of the most widespread and 

 common of the Hickory galls in the Mississippi Valley, and was 

 frequently sent by correspondents for identification. The galls 

 begin to form the latter part of May and are then almost globular, 

 though somewhat more prominent above than beneath, with a 

 scarcely noticeable nipple on the under side, densely covered with 

 yellowish pubescence. Their color is a deep purplish -brown, 

 contrasting prettily with the light green color of the young leaves ; 

 their surface above and beneath is more or less roughened or 

 granulated, and the appearance reminding one strongly of the 

 galls of Cecidomya q.-pilulcB of the oak. 



By the first week in June the galls are fully grown, but only 

 contain the stem-mother, her eggs and larvae. By the middle of 

 the month the winged female prevails, with but few pupae and 

 still fewer larvae, while in many cases the galls have opened and 

 migration has actively begun. 



The transverse diameter of the matured gall varies from 

 2_yram. j^jj^ tjjgi^ vertical diameter from 2-5"""- Many of them 

 are almost globular, and, as a rule, more prominent above than 

 beneath. Occasionally, however, they are more prominent 

 beneath. In the majority, especially the larger galls, the under 

 side is considerably sunken beneath the surface of the leaf and 

 much less conical and usually much paler than when younger. 

 The color above is a dull, dark purplish brown, sometimes, how- 

 ever, with only a brownish shade, or entirely of a dull greenish- 

 yellow. The surface above, and sometimes slightly beneath, is 

 densely and quite coarsely rugose and more or less distinctly 

 pubescent, especially beneath, and covered with a more or less 

 noticeable sticky or viscid excretion. The orifice is more densely 

 pubescent than the rest of the gall, and splits, when mature, into 

 4-8 short bracts. The walls of the galls are rather stout, leathery 

 and flexible. At full growth the inside is almost pure white, 

 but by the time the insects are ready to leave, the color is brown 

 all through. Generally these galls grow singly, though there 



