The Basal Sclerites of the Leg in Insects. 13 



the trocliantin is supra-coxal (i. e. above, or dorsal to the coxa) 

 and is therefore not sub- coxal (i. e. below, or ventral to the coxa) 

 in position ! Furthermore, it is extremely doubtful that the trochantin 

 is a basal portion of the leg, as is maintained by those who term 

 it the "subcoxa", and as is implied by the latter designation. On 

 this account, the application of the term "subcoxa" to the trochantin, 

 is not only useless, but misleading. 



Of the varied and heterogeneous collection of sclerites to which 

 Berlese, 1909, applies the designation "subcoxe o trochantini", only 

 the plate which he terms the "subcoxe" in his fig. 197 of Acridium 

 (i. e. the plate labeled sc in Fig. 16, of the present paper) is appro- 

 priately designated, since it is the only one situated ventral to, or 

 below the coxa (i. e. is sub-coxal in position). This sclerite, however, 

 is merely a region of the sternum, and is not at all homologous with 

 the plate which Berlese calls the "subcoxe o trochantini" of the 

 meso- and metathorax in his fig. 196 of Gnjllus (i. e. a plate homo- 

 logous with the plate designated as 1st in Figs. 3 and 19, of the 

 present paper). Furthermore, the plate which Berlese terms the 

 "subcoxe trochantini" in his fig. 185 of the thorax of Cicada 

 (i. e. in of Figs. 10 and 12 of the present paper) is not homologous 

 with either of the above mentioned sclerites. It is apparent that 

 the term subcoxa cannot be applied to all of these diff'erent sclerites 

 without creating confusion, so that it is preferable to restrict the 

 term subcoxa to the episternum, together with the pre-coxal bridge 

 connecting it wùth the sternum, as was done by Heymons, 1889 

 (who introduced the term subcoxa), and to apply the term trochantin 

 only to the sclerite so designated in the present paper. 



Jordan, 1902, considers that the upper marginal region of the 

 coxa, cm (Fig. 6) in certain Trichoptera, represents the trochantin. 

 The trochantin, however, is included in the region designated as 

 ptn in Fig. 6, since this region includes the projection articulating 

 with the coxa, while the marginal region cm of Fig. 6, is merely 

 the upper portion of the veracoxa, vc, and is homologous with the 

 sclerite designated as cm in Figs. 9, 8, 3, 2, etc. 



The composite region ptn of Fig. 8 (of Conjdalis) is designated 

 as the trochantin alone by Snodgrass, 1909, who is consequently 

 forced to assume that the small plate aes (Fig. 8) represents the 

 entire episternum {es, of Figs. 1, 2, 3, etc.). It has already been 

 shown, however, that the homologue of the episternum always extends 

 from the top to the bottom of the pleural plate, so that the sclerite 



