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TEXT-BOOK OF ENTOMOLOGY 



rni 



(Ascalaphomerus, Macronema, Rhyacophila, Hydropsyche, Am phi- 

 psyche, Smicridea, and Ganonema) the lower pair are 2-jointed like 

 those of Ephemeridse. The number of abdominal segments in the 

 adult Trichoptera is nine, and McLachlan states that the genital 



armature consists of three pairs of 

 appendages, i.e. a superior, inferior, 

 and intermediate pair, besides the 

 suranal plate (vestige of a tenth seg- 

 ment) and the penis. Judging by his 

 figures, these three pairs of append- 

 ages arise from the last or ninth uro- 

 mere, and the upper pair seem to be 

 the homologue of the cercopoda of 

 ephemerids. It needs still to be 

 FIG. iyy. End of abdomen of embryo ascertained whether the intermediate 



of Mantis: r, rhabdopod; o, cercopod; sp, 



suranal plate; si, stigma on sth segment, pair is a separate set, or merely sub- 



After Heymons. . . , , 



divisions of the upper or lower, and 



whether one of the latter may not arise from the penultimate seg- 

 ment, because we should not expect that the last segment should 

 bear more than one pair of appendages, as we find to be the case 

 in arthropods in general, and in the Neuroptera. from which the 

 Trichoptera may have originated. 



In most larvae of the Trichoptera, especially the Rhyacophilidse 

 and Hydropsychidse, the last abdominal segment bears a pair of 

 2-jointed legs (cerco- 

 poda), ending in either 

 one or two claws, which 

 under various forms, 

 sometimes forming long 

 processes, persist in the 

 pupa ; and there appears 

 to be a suranal plate, the 

 vestige of the tenth uro- 

 mere. In the pupa, 

 judging by Klapalek's 

 figure of Leptocerus 

 (24 8)!) , 25), a pair of lat- 

 eral spines arise which 

 may in the imago form one of the pairs of appendages or styles. 

 In the pupa of (Ecetis furva his figure 28 9 shows two pairs of 

 1-jointed appendages arising from the last segment; whether the 

 long dorsal or upper styles arise from the vestige of a more distal 



FIG. 200. End of abdomen of Periplanela americana, 

 tf, side view: c. cercopod: '. stilus: />. penis: t. titillator ; 

 d, "bird's head" (clasper?); , " oblong plate "; IX XI, 

 terminal segments: X. suranal plate: XI, llth sternite. 

 After Pevtoureau. 



