Stylojndce. 1 1 



maturity ; involving a corresponding detention for their 

 associated dependents: which, after their long pro- 

 tracted larval condition as aforesaid, must, from the same 

 inevitable necessity, produce their young the self-savte 

 year in which they themselves complete their transforma- 

 tions, in order that (like the Stylopides) their brood may 

 obtain access to the future larva-cells of their non-hyber- 

 nating foster-parents. 



These very distinct groups must necessarily be divided 

 into different subfamilies, readily distinguished from each 

 other ; the true Xenides (nurtured by the social wasjjs) 

 having- the two exarticulate branches of the antennse 

 tapering, sinuous, and divergent; whereas in the others, 

 which I would distinguish as Fseudoxenides, they are 

 compressed, forcipate, and recumbent. 



This latter group, however, as thus separated from the 

 true Xenides, comprises in itself the fosterlings of two 

 very dissimilar tribes; namely, of the Eumenidce, and 

 other solitary wasps on the one hand, and of the 8pliegidce^ 

 with their fossorial allies, on the other. When, therefore, 

 we find, in other instances, different genera, and different 

 species, of the same nurturing tribe, maintaining exclusive 

 associations with their respective foster-dependents, how 

 much the more might not the same principles be held to 

 apply to the dependents of different tribes, not indeed 

 so utterly irreconcilable with each other, as to preclude 

 all possible intercommunion of race between such sub- 

 sidiary groups from adventitious circumstances ? 



It remains, therefore, to be seen, how far the lines of 

 demarcation which separate these fostering tribes may 

 be more or less ostensibly reflected in their foster- 

 progeny. 



But, amid the -numerous instances in which the esuvite 

 of male Stylopidce, or their derelict females, have been 

 met with among the different genera of Fossores, Latr. 

 (as tabulated in the sequel), the European Xenos Spheci- 

 darum, and the Brazilian Xenos Westiuoodii, described and 

 figured in our Transactions by Mr. Templeton (/;) , have 

 alone been detected hitherto in the winged form; to 

 which I am now enabled to add a third species obtained 

 on several occasions (both males and females) from one 

 of the European Nyssonidee. 



(h) Second series ; Vol. III. p. 51. 



