STATK HORTICULTURAL SOCIETY. 141 



It will be seen by reference to this table, that according to this 

 arrangement the Plant-lice are divided into three families — Psyllidce, 

 Aphidce and Aleurodidcc — but some authorities, especially those of recent 

 date, are disposed to include the last in Aphidce, thus dividing the group 

 into but two families. 



As this paper is only preliminary to a more extended article on these 

 insects in my next report, I vvill not devote any further space at present 

 to the discussion of the arrangement and classification. I will also, for 

 the same reason, occasionally mention some species which I am at present 

 unable to describe, and some which I have no positive evidence are found 

 in this State. This is done for the purpose of calling attention to them, 

 with the hope that those who read this paper may give a little more than 

 usual attention to these insects during the coming summer, and send me 

 such as they think are new, or not fully described herein. In other 

 words, it is intended not only for the benefit of our horticulturists, but 

 also as an aid to all those, who may desire to do so, in studying these 

 singular and important insects ; and to call forth as many facts as possible 

 in reference to them, for my next report. 



In order to prevent repetition, I will defer the further account of 

 their history, character and habits, giving those applicable to the different 

 families in their proper connection. 



PsYLLiD.i;. (Jumping Plant-hce.) 



As but few species of this family belonging to our American fauna 

 have, as yet, been described, although doubtless many are to be found 

 here, I will give the family and generic characters with a little more 

 particularity than I should otherwise do. 



They are similar in appearance to the ordinary plant-lice, but the 

 head is broader and resembles, somewhat closely, the head of a little leaf- 

 hopper; it is short and generally triangular in front, and usually deeply 

 cleft in the middle of the front; the eyes are lateral and prominent; 

 and, in addition to these true eyes, they are furnished with three ocelli, 

 or little simple eyes, placed on the top of the head in a triangular form, 

 one close to the inside of each eye and one on the middle of the front 

 where the cleft or notch commences. The antennee, which are rather 

 long, slender and thread-like, present' the most prominent characteristic 

 for distinguishing the family, in the two little bristles with which each 

 is always furnished at the tip ; they are usually ten-jointed, though in 

 some species there are but nine or even eight, and, if I am not mis- 

 taken, in one American species there are eleven; the basal joint is usually 

 thick, and in one genus the second joint is greatly dilated. The beak is 

 short and three-jointed, arising almost between the fore-legs. The hind 

 margin of the sternum or breast usually terminates on each side with a 

 little spine. The wings, which occur in both sexes, are four in number, 

 and when at rest are placed over the abdomen in the form of a very steep 

 roof; the front pair have a strong mid-rib or mid-vein running through 

 the middle and dividing near the center into three principal branches, 

 each of which is usually further divided into two branches; the veins of 



