THE JUMPING PLANT-LICE OE PSYLLID^ OF THE NEW WORLD. 13 



and more reduced than in Apsylla. The trochantin is larger and 

 articulates with the coxa in front and well below the upper end. 

 Along this margin of the episterum next to the trochantin inside 

 there is a ridge, which extends upward along the corresponding 

 margin of the epimeron and articulates with the coxa at its upper- 

 most point and passes on downward behind the coxa to unite with 

 the corresponding process from the other side and with the sternum, 

 as described for Apsylla. 



The metacoxa is similar to that of Apsylla, except that it is much 

 larger and the posterior thickening is more marked and conspicuous, 

 while the anterior part is thinner. Stough went widely astray in 

 his interpretation of the metathorax. The thickened posterior part 

 of the metacoxa he called the epimeron and the remainder he called 

 the coxa. The pleurites he did not attempt to explain or show, 

 except his supposed epimeron. 



The sternum of the metathorax is, in the generalized Apsylla, 

 rather similar to that of the mesothorax, but much smaller. It is a 

 narrow, though easily visible, sclerite between the meso- and meta- 

 coxse with a narrow projection extending back between the metacoxee 

 and mostly covered by them so that it is scarcely visible from directly 

 beneath. This narrow process articulates with the two prolongations 

 from the two epimera which project downward behind the coxse. 



The metafurcx arise from the posterior part of the sternum ventrad, 

 near the point from where the posterior prolongation begins. They 

 are about one-half larger than the mesofurcse and of similar shape 

 and form, except that the apices are more flattened out and broad- 

 ened (fig, 12). The lateral apodemes are small but distinct, and 

 show plainly the position of the pleural suture (figs. 2, 12). 



In Psylla, and practically all the genera except Apsylla, the 

 sternum and metafurcse are very much more complicated. The 

 sternum is scarcely visible from beneath, except a small sclerite at 

 the lower end of each metepisternum. This extends upward (shown 

 in fig. 1 by dotted lines) between the meso- and metacoxEe, and is 

 visible only by dissection, being concealed by the coxae (figs. 10, 11). 

 The posterior prolongation is, therefore, a little farther up from the 

 venter and is larger and longer because the metacoxae are larger 

 and it must reach to the posterior margin of the latter. At the 

 posterior margin of the coxae the sternum articulates with the pro- 

 longations of the epimera in exactly the same manner as in Apsylla. 



The metafurcae are not simple and small, as in Apsylla, but are 

 exceedingly long and complicated (figs. 10, 11) in their structure and 

 articulations with the other parts of the body. The two main forks 

 of the furcae pass upward arcuately to the dorsum of the metathorax 

 and extend backward to beyond the posterior margin of the post- 

 scutellum, projecting into the base of the abdomen. About half 



