190 DAVENPORT ACADEMY OF SCIENCES. 



SECTION I. 



Phyhoxera cary^-septum (Shinier). 



Plate i., figs. 1-6; Plate ix., fig. 46. 



Dactylospfmra c. -septum Shinier. Trans. Am. Ent. See. , II. , p. 389. 

 Phylloxera c.-septa Riley. 7th Ann. Rep. Nox. & Ben. Ins. of 



Mo., p. 118. 

 Phylloxera c.-septa Thomas. 8th Rep. Nox. & Ben. Ins. of 111., p. 



164. 



The galls of this species, especially those of the more typical 

 form, are the handsomest and largest of this group. Their trans- 

 verse diameter at the plane of the leaf ranges troni 5 to 12™™- and 

 their vertical diameter from 4 to 6"""-. They are quite convex 

 on both sides and generally more conical and more prominently 

 projecting above than beneath, especially so in the smaller speci- 

 mens. All are provided with a nipple on both sides, the upper 

 one stouter and more prominent, with its base more or less sunken 

 below the plane of the gall. Both nipples, particularly the lower 

 one, lean frequently somewhat towards one side. Both openings 

 are either round or oval and fringed by about eight stout or 

 slender filaments. The opening on the under side closes gradually 

 so that the insects are compelled to leave from above. The 

 consistency of the galls is dense, though rather thin, paper-like, 

 and more or less transparent, crisp, and stoutest at the junction 

 with the leaf. The cavity, if cut vertically, appears to be more 

 or less hexagonal at the central portion, more or less pointed 

 towards the nipples, and quite flat at the median circumference, 

 with the exception of a ridge which indicates the former division 

 of the gall into two compartments while young. The color above 

 is variable. Some are of a darker or lighter bright red or pale 

 rose, with a pale greenish margin around the base, while others 

 are pale yellowish green, the nipple more or less brown, sur- 

 rounded at base by a pale reddish ring. The color of the under 

 side corresponds either more or less with that of the upper side 

 or is of the same color as the leaf, or paler. In its younger stage, 

 while still quite small, it is most beautiful and has \(try little 

 resemblance to the fully grown gall. 



