328 Mr. F. Walker's Descriptions of Aphides. 



with which I am acquainted, I do not see how it can be placed 

 in any other genus. 



Grammitis blechnoides (nob.) ; fronde coriacea, utrinque attenuata, 

 profunde pinnatifida, soris lineari-oblongis, subobliquis, numerosis. 



Fronds numerous, from a creeping rhizoma which is densely 

 covered with pale reddish brown scales, lanceolate, coriaceous, 

 glabrous, seven to nine inches high, attenuated at each extremity, 

 pinnatifid almost if not quite to the rachis, the segments alter- 

 nate, entire, linear, obtuse, about half an inch long in the widest 

 part of the frond, diminishing gradually in size below until they 

 disappear a few lines from the rhizoma. Veins simple, internal. 

 Sori oblong or linear- oblong, slightly oblique, arranged in a line 

 on each side between the midrib and the margin, somewhat sunk 

 in the thick substance of the frond. 



EXPLANATION OF PLATE XVIII. 



Fig. 1. Grammitis blechnoides, natural size. 



Fig. 2. One of the segments, a portion of its substance removed to show the 



venation. 

 Fig. 3. Sori. 

 Fig. 4. Capsules. 

 Fig. 5. Seeds. — Figs. 2-5 magnified. 



XXXVI. — Descriptions of Aphides. By Francis Walker, 



F.L.S. 



[Continued from p. 260.] 



Fourth Group. 



The chief peculiarity of the only species in this group is the 

 abundance of cottony filaments which emanate from its body, 

 and it resembles the preceding Aphis in the shortness of its nec- 

 taries and of the seventh joint of its feelers. 



6. Aphis Fagi, Linn. 



Aphis Fagi, Linn. Syst. Nat. ii. 735. 23; Faun. Suec. 994; 

 Geoff. Ins. i. 497. 12 ; Reaum. Ins. iii. t. 26. f. 1 ; Fabr. Ent. 

 Syst. iv. 214. 24; Syst. Rhyn. 297. 24; Burm. Handb. der 

 Ent. ii. 92. 2. 



Lachnus Fagi, Kalt. Mon. Pflan. i. 147. 1. 



The viviparous wingless female. This appears on Fagus sylva- 

 tica, the beech, before the end of April ; as soon as it is hatched 

 from the egg it resorts to the veins of the young leaves, and is 

 then pale green or yellow, very small, long, narrow, slightly con- 

 vex, nearly linear, or somewhat increasing in breadth towards the 

 tip of the abdomen ; its sides are covered with white filaments : 

 the feelers are filiform or slightly setaceous, dark green, paler at 



