PROC. ENT. SOC. WASH., VOL. 21, XO. 6, JUXE, 1919 l.'u 



putium has come to have a definite and universally accepted 

 meaning among the dermapterists, who apply this term to that 

 portion of the penis within which the "glans" is retracted, and 

 since the other application of the designation praeputium to the 

 basal segments of the gonopods by a few of the workers on the 

 sawfly group is not recognized as a valid usage in any glossary, 

 textbook, or general work, I prefer to give the term praeputium 

 its general and widely accepted application namely to restrict 

 its application to the above-mentioned parts of the penes of the 

 Dermaptera, for which it is unusually appropriate. Similarly, 

 the designation "manubrium" cannot be applied to the parapenes 

 "pa" (Fig. i), as is done by a few students of the sawfly group 

 without creating unnecessary confusion, since the term manu- 

 brium has come to have a definitely established and widely ac- 

 cepted application to the base of the spring in Collembola, and 

 any attempt to apply it to other structures, such as the projecting 

 portion of the mesosternum of the Elateridae, or to the adbominal 

 sterna of certain earwigs, etc., should be abandoned if we are 

 ever to have any uniform terminology applicable to all of the 

 orders of insects as students of wing-venation are attempting 

 to establish. 



In a male of the roach Periplaneta americana (shown in Fig. 

 77 of a paper by Crampton, 19183), it may be seen that the pair 

 of appendages borne on the plate situated below the anus, are the 

 styli, while the cerci are situated above the anal opening. Simi- 

 larly, in the ephemerid shown in Fig. 58 of the present paper, the 

 segmented appendages "s" borne on a plate situated below the 

 anal opening are arthrostyles, or segmented styli, while the*cerci 

 "c" are situated above the anal opening. Since the segmented 

 appendages borne on the plate situated below the anal opening 

 "a" of the larva of Neurotoma shown in Fig. 44 occupy a situa- 

 tion similar to that of the segemented appendages "s" of the ephe- 

 merid shown in Fig. 58, I would homologize the segmented ven- 

 tral appendages of the Neurotoma larva ("s" of Fig. 44) with the 

 arthrostyli or segmented styli "s" of the ephemerid shown in 

 Fig. 58. On the other hand, the small cornicles labeled "c" in 

 Figs. 43 and 47 of the larvae of Pteronidea and Treinex are located 

 above the anal opening "a" and are probably homologous with 

 the cerci "c" of lower insects (Fig. 58, etc.). MacGillivray, 1913, 

 would call both the structures labeled "c" in Figs. 43 and 47, 

 and those labeled "s" in Figs. 44 and 48, "anal cerci." That the 

 two types of structures are not the same may be readily seen by 

 comparing together the larva of Cephus and that of Trcmcx 

 (Figs. 47 and 48). In both of these wood-boring larvae, as well 

 as that of Sirex and similar forms, there occurs of postcornus 



