32 Psyche [February 



ing parallel to the margin (but at some distance from it) in the 

 fore wing. The nature of the thoracic sclerites of the Homop- 

 tera would lend further weight to the view that the ancestors 

 of the Homoptera were very like those of the Neuroptera, and 

 the fact that many insects descended from the common Neurop- 

 teroid stem, such as the Mecoptera (and even the Siphonaptera) 

 exhibit very similar tendencies in the specialization of their 

 mouth-parts (which tend to lose the ligula, while the labial palpi 

 become approximated and unite to some extent, and the maxil- 

 lae become much elongate and somewhat stilet-like) would suggest 

 that they and the Homoptera inherited these tendencies from 

 a common ancestry. Furthermore, the fore wings of certain 

 primitive Trichoptera and Mecoptera, which were derived from 

 a common Neuropteroid stem, show undoubted affinities with 

 certain types of Homopterous fore wings, and lend further 

 weight to the supposition that the ancestors of the Homoptera 

 resembled those of the Neuropteroid insects in many respects. 

 Thus, the Trichopterous fore wing shown in Fig. 27 is remarkably 

 like that of the Homopteron shown in Fig. 29, especially in the 

 character of the anal and cubital veins; and the other veins of the 

 wing are also of much the same type in the two wings under con- 

 sideration. All of these facts, which indicate that the ancestors 

 of the Homoptera and Neuroptera were very closely related, 

 are in harmony with the fact that the Homoptera and Psocids 

 are also very closely related, since the Psocids themselves are 

 clearly related to the Neuroptera, and their line of development 

 apparently merges with that of the Neuroptera near its point 

 of origin, thereby involving the line of develpoment of the 

 Homoptera with that of the Neuroptera through their mutual 

 relationship to the Psocids, as well as through the more direct 

 affinities of the Homoptera themselves with the Neuropteroid 

 insects. I have therefore maintained that the ancestors of the 

 Homoptera were intermediate between those of the Psocids and 

 those of the Neuroptera, and the present study of the fore wing 

 venation would uphold the correctness of this view. 



If one compares the wing of a Neuropteron such as the one 

 shown in Fig. 34, with the wing of a Protoblattid such as the one 



