THE WINGS OF PSYLLID.E 283 



The second and third aiials of the fore iving. — The second and third anal 

 trachese in the fore wing are well developed and the third anal is frequently 

 two-branched (Fig. 284, 3). 



The costa and the subcosta of the hind wings. — In all of the Jassida^ 

 proper the hind wing is very uniform. No costal or stibcostal tracheae have 

 been disco\'ered although the subcostal vein was well defined in all of the 

 older nymphs studied (Fig. 2 84, q). 



The radius of the hind wing.— The radial trachea of the hind wings is 

 typically two-branched in this family. In a single genus Spanghergiella, 

 the radial trachea is unbranched. No indication of trachea Ri was observed 

 in the hind wing. 



The media of the hind wing. — The medial trachea of the hind wing is two 

 branched in all of the genera examined. 



The cubitus of the hind wing. — The cubital trachea of the hind wing is 

 reduced to an unbranched condition in all of the genera examined. 



The anal tracJiece of the hind wings. — The first anal trachea and the 

 cubital trachea coalesce for a distance as in the fore wing. The second 

 and third anal trachccC are also present in nearly all cases; and the third 

 anal trachea is frequently two-branched. In the adult wing the second 

 anal vein and the anterior branch of the third anal frequently coalesce at 

 the base or anastomose near the middle of their course. 



The basal connections of the trachece of the wings. — The above abstract, 

 which consists largel}- of quotations from the paper by Metcalf, indicates 

 the more important conclusions reached by this writer. A study of his 

 illustrations indicates another conclusion not mentioned by him; this is 

 that in the Jassidae, as in the Membracidge, a transverse basal trachea has 

 not been developed. With one exception, in all of the forms where the 

 basal connections of the tracheae were traced, the costo-radial and the 

 cubito-anal groups of tracheae are not connected by a transverse basal 

 trachea, and the medial trachea is a member of the costo-radial group. 

 Several illustrations of this are on the single plate reproduced here. (Fig. 

 284, 2, 5), and there are many of them on the other plates in Metcalf's 

 paper. 



The one exception to this arrangement of the tracheae indicated by 

 Metcalf's figures is that of the hind wing of Gypona (Fig. 284, 9). As the 

 basal connections of the tracheae are only partly shown in this figtu^e the 

 evidence presented by it is not conclusive. 



{e) THE WINGS OF THE PSYLLID^ 



We are indebted to Miss Patch ('09) for the working out of the homol- 

 ogies of the wing veins of the Psyllidas. The following account is based on 

 her paper. See note on page 291. 



