STRUCTURE AND DEVELOPMENT OF EMBIA TEXANA. 



103 



in the adult. Owing to this double venation, which, judging 

 from the figures, occurs also in a number of the other species, 

 there has been much confusion in homologizing the veins with 

 those of other insects. On applying the ontogenetic method of 

 Messrs. Comstock and Needham, which fortunately the possession 

 of nymphs of two species enables us to do, it will be seen that 

 the interpretation given by these gentlemen of one of Wood- 

 Mason's figures is nearly correct. It might be suggested, how- 

 ever, that the cross-veins are not to be regarded as branches of 



FIG. 2. a, wing of adult ; b, wing of nymph ; c, wing of Embia Uhrichi. 



the radius, but as additional veins, for their position is very un- 

 stable, and moreover, in the nymph they are indicated merely by 

 a sinuosity on the radius, very much as in Psocus? from which 

 type they do not materially disagree. Texana has the simplest 

 type of true neuration of any of the species of this family, the 

 veins being reduced to those thickenings mentioned before. Fig- 

 ures of its nymph-wing, which is also identical with that of maitri- 

 anica, and of the adult wing of Uhrichi (copied from Saussure) 2 

 are given for comparison. In the latter species the neuration 

 reaches its highest degree of complexity. 



If before the final moult wing-formation does not take place, 

 the adult stage is attained in a wingless condition. These wing- 

 less males are more frequently met with in the nests than the 

 winged form, though never more than one was to be found in a 



1 Vide, American Naturalist, XXXII., p. 241, Figs. II and 12. 



2 Mitt. d. Schweiz. entom. GeselL, 1896, PI. Fig. I. 



