262 ENTOMOLOGICAL NEWS ! XXXl'i, '21 



is merely another instance of the many misinterpretations of 

 the parts of insects current in entomological literature, which 

 owe their origin to the fact that entomologists in general have 

 not been willing to take the time to examine thoroughly a few 

 of the commoner Crustacea, before attempting to determine the 

 correct interpretation of the parts in insects. 



Walker, 1919 (Annals Ent. Soc. America, Vol. 12, p. 287) 

 maintains that I am mistaken in homologizing the exopodites 

 or paraprocessi, r.r, of Fig. 11 with the styli borne on the 

 abdominal segments of Machilidae, etc., but the styli are clearly 

 the homologues of the exopodites of crustacean appendages, 

 and the structures labeled ex in Figs. 11 and 12 are also clearly 

 homologous with the exopodites of crustacean appendages, so 

 that Walker's objection is not valid in this instance, since things 

 homologous with the same thing are homologous with each 

 other, and the appendages r.r of Fig. 11, being homologous 

 with the exopodites of crustacean limbs, are also homologous 

 with the styli of J\Iaclii!is, etc., as Walker would have seen had 

 he made a study of Crustacea as well as insects. We may 

 carry the comparison of parts still further, and state that all 

 representatives of the exopodites of a crustacean limb, such as 

 the "paraprocessi" labeled r.r in Figs. 11 and 12, or the styli 

 (labeled .? in Fig. 2) borne on the valves of the ovipositor of 

 certain insects, or the gonopods (outer claspers) of certain 

 male insects, or the styli borne on the abdominal segments of 

 Thysanura, etc., are at least serially homologous ( homo- 

 dynamous), while all structures representing the endopodites 

 of a crustacean limb, such as the cerci labeled en in Figs. 12, 

 11, etc., or the inner valves of the ovipositor, labeled /r in Fig. 

 2, or the penis valves of certain male insects, are likewise 

 serially homologous, and the same is true of the basal plate 

 labeled pr in Figs. 11, 12 etc., or the dorsal (and ventral) 

 valves of the ovipositor labeled TV in Fig. 2, or the so-called 

 "coxites" of the genitalia (gonopods) of male insects, all of 

 which are apparently homologous with the protopodite, pr, of 

 the crustacean shown in Fig. 14. This matter will be more 

 fully discussed in a paper dealing with the genitalia of insects 

 in general, however, and need not be further discussed here. 



