﻿565. 



PSYLLA FRAXINI. 



Chermcs of the Ash. 



Order Homoptera. Fam. Psyllidse. 



Type of the Genus, Chermes Betulse Alni Linn. 

 PsYLLA Geo/., Lat., Curt. — Chermes Linn., DeG,, Fab., Gmel. 



AntenntB inserted before the eyes, sometimes as long as the body, 

 filiform, 10-jointed, basal joint stout subquadrate, with a few 

 bristles, 2nd small and oblong, remainder very slender, 3rd joint 

 longer than the 4th, the following slightly increasing in length 

 to the 9th joint, which is not longer than the 4th ; 10th joint 

 considerably shorter and terminated by 2 unequal bristles (4). 

 Labrum? elongate-ovate. 



Mandibles and Maxilla long slender setae, curved at the base (1). 

 Labium conducted from the head under the antejiectus and ap- 

 pearing between the coxae of the anterior legs (T 2) ; short stout 

 and triarticulate ; basal joint elongated, 2nd much shorter and 

 slenderer, 3rd suborbicular (2). 

 Head short but broad, deeply notched before (1, the upper side) : eyes 

 lateral, small globose and prominent : ocelli 3, om Me crown very remote. 

 Thorax subglobose. Abdomen short, that of the male furnished 

 towards the apex with a long erect hairy lobe, 2 others forming an 

 arch at the apex, ivith a short oblique process between them (A ^J ) .• 

 ovipositor exseried, rather large and a little curved, composed of an 

 oviduct inclosed by an upper and under valve, and 2 lateral ones 

 united at the base ( ?). Wings deflexed in repose, superior very 

 ample, elongate ovate, with S furcate nervures ; inferior smaller, with 

 very indistinct nervures. Legs short, hinder pair a little longer and 

 formed for leaping ; coxae, posterior with a strong spine beneath : 

 tibiae loith minute spines at the apex, hinder pair the longest, ivith 

 a hook outside at the base: tarsi short and biarticulate : claws hooked; 

 pul villi small (Sf, hind leg, including the coxa). 

 Pupae suborbicular and depressed. 



Fraxini Linn. — Curt. Guide, Gen. 1050. n. 15. 



Yellow, variegated with orange and black: tips of the clypeus, 

 a triangular spot on the crown of the head, an interrupted circle 

 on the thorax and the scutellum (excepting 2 yellow spots), 

 black : abdomen banded with the same colour : superior wings 

 with the nervures ochreous except at the apex, which is margined 

 with brown, forming 3 or 4 irregular spots, basal angle brown 

 with a short black line at its insertion : inferior wings with a 

 brown stripe on the anal angle : centre of the thighs and tips 

 of tarsi and antennae black. 



In the Author's and other Cabinets. 



Psylla is a very numerous genus, which has been but httle 

 attended to. Linnaeus only gives their names, which, hke the 

 Aphides, are for the most part derived from the plants that 

 they inhabit. Many species in their larvae and pupse states 

 are clothed with a white fleecy and cottony substance, and 

 their excrement forms threads or masses of a glutinous and 



