342 Annals Entomological Society of America [Vol. VI, 



ordinary methods of dissection. If the wing is carefully 

 removed, however, the relationships of the main tracheae 

 need not be disturbed. Some emphasis has also been placed 

 on the fact that in some families the tracheae of the wing pads 

 arise from a single basal trachea, whereas in certain other 

 families the radio-medial group of tracheae arises from a cephalic 

 body trachea while the cubito-anal group arises from a caudal 

 body trachea. In certain cases this character has been used 

 to indicate that one family is more primitive structurally 

 than another. That such a position is untenable is clearly 

 shown in at least two genera of the Fulgoridae in which I was 

 so fortunate as to secure enough of the body tracheee as to 

 determine this point. In Thionia (Figs. 27, 28) the tracheae 

 of the fore wing pad arise from a single body trachea while the 

 tracheae of the hind wing pad arise from a cephalic and a caudal 

 body trachea. In Amphiscepa (Figs. 5, 6), on the other 

 hand, the tracheae of the fore wing arise from two body trachese 

 whereas the tracheae of the hind wing arise from a single body 

 trachea. 



THE FORE WING. 



Unlike the fore wings of the Jassidae, the fore wings of the 

 Fulgoridae are exceedingly variable. As is well known, the 

 adults of many Fulgoridce occur in two forms, a long-winged 

 or macropterous form, and a short-winged or brachypterojis form. 

 This is especially true of certain genera. While the problem 

 of the origin and significance of this variation is an exceedingly 

 interesting one, it has not been taken into consideration in 

 this paper, and as a rule, only macropterous forms have been 

 considered with the exception of a few cases where the brachyp- 

 teroiis forms are the usual ones. 



The wings of the Fulgoridae show two marked forms of 

 specialization from the hypothetical type, the one by the ad- 

 dition of accessory branches to the main veins and the other 

 by the reduction of the number of branches of the main veins. 

 The one may be known as specialization by addition, and the 

 other as specialization by reduction. An almost perfect 

 series can be traced from the one extreme to the other. Forms 

 like Ormenis (Fig. 13), show as great specialization by addition 

 as is found in any insect of any order, while forms like Briich- 

 omorpha (Fig. 33), show a great deal of specialization by re- 



