AMERICAN PSYLLID.E I (Triozinae) 



D. L. CRAWFORD 



Although the Psylhdae have been quite thoroughly studied in Europe, 

 chiefly by Dr. Franz Low, still the knowledge of the group in America is very 

 scanty. A few papers have been published by E. A. Schwarz and by the late 

 Mr. Riley and others, but no attempt has been made in America to systematic- 

 ally study this most interesting and important group as a whole. The large 

 collection of Psyllidae presented to Pomona College by Prof. C. F. Baker, and 

 also the extensive C. F. Baker collection from the National Museum at Wash- 

 ington are now before me for systematic study. These collections include 

 specimens from the majority of the states, and also from Mexico and Central 

 America. 



In this first paper, I present a provisional key to the genera and species of 

 the subfamily Triozinae, together with the first installment of descriptions of 

 the new species. Although the key is only provisional and will probably be 

 extensively revised before the completion of the work, still I have chosen what 

 seemed to me after very careful comparative study of the two collections to be 

 the best diagnostic characters. It is quite possible that a few of the American 

 species will be found to be identical or closely related to some European forms ; 

 representatives of many of the European species have been placed at my dis- 

 posal, but not enough of them to make a systematic comparison. 



In making the synopsis of genera of the subfamily, I am unable, from Mr. 

 Scott's characterization of his genus Petalolyma, to find any generic differences 

 between that genus and the typical genus Triosa. From the brief and wholly 

 inadequate descriptions of Trioza diospyri Ashmead, T. magnoliae Ashmead 

 and T. pxrifoUac Forbes, it is impossible to include these in the synopsis of 

 species ; it seems quite probable, however, that T. magnoliae is closely related 

 to Paratrioaa arbolensis u. sp. 



In this and subsequent studies, the term facial cones is applied to the 

 conical structures projecting outward or downward from the face ; the term 

 frontal plates is applied to the flat discal area of the upper anterior portion of 

 head, whether that area is raised plate-like or not. 



SYNOPSIS OF TJIE GENERA OF THE SUB-FAMILY TRIOZINjE 

 A. Radius longer than basal portion of subcosta. 



I). Facial cones entirely wanting. Fore femora long and distinctly lirnad- 

 encd Rliinopsylla Riioy. 



BB. Facial cones not entirely wanting. 



C. Labrum very large and distinctly visible below and between facial 

 cones ; facial cones extremely short and very broad and broadly 

 rounded when viewed from in front, with antennae inserted near 

 their base ; cones slightly projecting beyond insertion of antennae. 

 Paratrioza n. gen. 



