THE ARTHROPODA 



97 



same general characters, but are progressively reduced in size 

 till the last of the series is no larger than a single endite of the 

 first postgenital limb. 



In the rarely found males of Apus the genital limb does not 



Fig. 22 



Appendages of the right side of Apus cancriformis. I. The two-jointed first 

 antenna. //. The second antenna, in the specimen figured it is exceptionally 

 composed of two joints. V. The second maxilla, showing the excretory pore, 

 ex. VI. The first thoracic limb. XVI, The oostegopod or genital limb of the 

 female. XVII. The first abdominal or postgenital limb. 7, the first endite or 

 gnathobase ; 3,3, 4,^, 6, the remaining five endites ; sa, sub-apical lobe ; Br, 

 bract; Fl, flabellum. For further description see text. Figs. V., VI., XVI., 

 and XVII. are reversed ; in their natural position the endites would be below, 

 the exites uppermost. 



differ from those immediately contiguous to it, but in the 

 female it is modified to form a receptacle for the eggs, and is 



II. G 



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