1920] Crampton — Genitalia of Male Hymenoptera and Other Insects 41 



" g " and " h ") of the trichopterous larva shown in Fig. 6(Plate III) . 

 The basal plate "p" of Fig. 6 (Plate III) has been provisionally 

 homologized with the styli-bearing plate "p" of Fig. 11 (Plate IV) 

 but this may prove to be incorrect. While it is quite probable 

 that the gonopods "s" of the adult Trichopteron shown in Fig. 15 

 (Plate IV) are homodynamous, or serially homologous, with the 

 gonopods labeled "s" in Fig. 6 (Plate III) of a larval Trichop- 

 teron, in the sense that the legs of the mesothorax are serially 

 homologous (homodynamous) with those of the metathorax, the 

 two structures in question may not be absolutely homologous, 

 since the gonopods or styli labeled "s" in the larval Trichopteron 

 (Fig. 6, Plate III) are apparently borne on the te7ith segment, as 

 is also true of the styli in certain larval sawflies, while the gonopods 

 of the adults may not belong to the tenth segment. The question 

 naturally arises as to whether the styli borne on the tenth segment 

 of the larval Trichopteron ("s" of Fig. 6, Plate III) form the 

 gonopods "s" of the adult (Fig. 15, Plate III) or whether they 

 represent the penis valves which unite to form the phallus of the 

 adult. The observations of Wheeler, 1893, who maintains that 

 the penis valves are appendages of the tenth segment, would lend 

 weight to the latter view; but it is much simpler to refer to both 

 styli "s" of larvae (Fig. 6, Plate III) and gonopods "s" of 

 adult insects (Fig. 15, Plate IV) as gonopods or gonostyles 

 regardless of the segment to which they belong; and for the sake 

 of convenience, this method has been adopted in the present 

 discussion. 



The dorsal region "ep" of the Lepidopteron shown in Fig. 13, 

 represents either a posterior prolongation of the ninth tergite, or 

 the fusion product of the tenth tergite with the ninth. The 

 lateral lobes "sg" are probably homologous with the copulatory 

 lobes "sg" of Fig. 21, or the lateral lobes "sg" of the Trichopteron 

 shown in Fig. 15. The structure labeled "pv" in the Lepidopteron 

 (Fig. 13) is the phallus or sedeagus, and the filament "b" possibly 

 represents the coiled filament "b" of Fig. 21. The harpago "h" 

 of the Lepidopteron is possibly the terminal segment of the gonopod, 

 whose basal portion has united with the ninth abdominal segment; 

 or the harpago "h" may represent the whole gonopod "s" of Fig. 

 15, although the former explanation is the more probable one. 

 The dorsal structure "ep" of the Lepidopteron (Fig. 13) is some- 



