242 



PSYCHE. 



[April 1S92. 



placed as to cover much of the leaf sur- 

 face. They develop on both surfaces 

 but in the specimens examined are 

 rather more common on the upper side. 

 This was collected at Blue Ridge, 

 Virginia, July 22, 1891, by Professor 

 A. B. Seymour. 



4. On the leaves of Acer spicatum. 

 Small felt-like patches of a whitish or 

 pale yellow color scattered over the 

 under side of the leaf. Growths on 

 leaves before me measure from 1.5 mm. 

 to 3 mm. in diameter. The growths 

 consist of rather long, tangled and dis- 

 torted hairs, being quite different from 

 anything else described in this paper. 

 The examples examined are probably 

 all young. Some of the older ones are 

 slightly brown rather than yellow, and 

 probably when aged would have been 

 decidedly brown in color. 



Temple, N. H., June iS, 18SS, 

 (from Prof. A. B. Seymour). 



5. On the leaves of Acer glabrnm. 

 An Erineum forming large patches 

 chiefly at the tips of the lobes and on 

 the upper side of the leaf. Growing 

 upon the veins as well as elsewhere. 

 On some young leaves before me, thickly 

 sprinkled also over the under surface. 

 This is the handsomest Erineum exam- 

 ined by me. The younger parts of 

 growths are bright purple in color; 

 older parts of growths become of a very 

 dark purple. The deformed hairs are 

 rather large, and are provided with long 

 stalks. The color, manner of growth, 

 and character of the deformed hairs will 

 serve to distinguish this Erineum from 

 the livid growth (No. S) which appears 



on the upper surface of leaves of A. 

 saccharimim. 



Glenwood Springs, Col., (collected 

 by R. E. Blount; communicated by 

 Prof. A. B. Seymour). 



6. On the leaves of Acer sacchari- 

 mim. A slender fusiform gall which 

 projects from the upper surface of the 

 leaf. Walls thin, and smooth inside 

 and out. Length about 4.5 mm. ; 

 greatest diameter 1 mm. Opening as 

 usual on the under side of the leaf. 



Central Illinois, common ; Temple, 

 N. H., (from Prof. A. B. Seymour). 



7. On the leaves of Acer sacchari- 

 mim. An Erineum forming patches 

 along veins on the under side of the 

 leaf. The patches are made up of great 

 numbers of minute mushroom-shaped 

 hairs with very short pedicels ; some- 

 times nearly sessile. The hairs and the 

 patches which they form resemble those 

 occurring on the under side of the leaves 

 of A. dasycarpum, but the hairs on the 

 latter, as far as examined, were pro- 

 vided with longer stalks, and were not 

 so much inflated at the extremity. The 

 patches in A. saccharimim, too, show 

 a tendency to develop along the main 

 ribs, whereas in A. dasycarpum they 

 are more scattered, often occurring 

 singly at the tips of lobes. They may 

 notwithstanding these differences prove 

 to be caused by the attacks of one and 

 the same mite. All of the examples 

 which I have seen were rather old and 

 were of a deep brown color, in one case 

 almost black. Individual patches meas- 

 ure as much as 10 mm. in diame- 

 ter. 



