The Basal Sclerites of the Leg in Insects. 9 



region spl of Figs. 11 and 14, as the "anterior portion' of the 

 sternum", and likewise interpret the region aes, of Figs. 11 and 14, 

 as the entire episternum. If we compare together Figs. 14 and 13, 

 however, it is at once apparent that the region aes of Fig. 14 is 

 liomologous with the region designated as aes in the Neuroptera 

 (Figs. 13 and 8); and it has already been shown that the region 

 aes of Figs. 13 and 8 is not the entire episternum, but is merely 

 the upper portion of the episternum which becomes marked off in 

 the roach (Fig. 2, aes) and other lower insects. In the same way, 

 by comparing Figs. 14 and 13 together, it is evident that the 

 region designated as spl in Fig. 14 is homologous with the compound 

 region spl of Fig. 13. In other words, it is the lower portion of 

 the episternum, etc. united with the sternum. The region spl 

 (Figs. 14 and 11) has been called the "sternopleura" by Diptero- 

 logists, and this designation (slightly modified to sternopleurite) 

 should be retained for the region in question. 



In the metatliorax of the beetle Dytiscus, a posterior region m 

 (Fig. 24) is marked off in the coxa. This posterior region, while 

 not strictly homologous with the meron of other insects (i. e. me of 

 all figures), corresponds in a general way to the meral region. 

 AuDouiN, 1824, who introduced the term trochantin, applied this 

 term to the region m of Fig. 24, in his figures of Dytiscus, and 

 AuDouiN likewise states that the trochantin articulates with the 

 epimeron, instead of with the episternum, although in some cases 

 he later correctly identified the true trochantin. Audouin's un- 

 fortunate mistake of applying the term trochantin to the region m 

 (Fig. 24) in Dijtiscus, is doubtless responsible for the incorrect 

 designation of the meron as the "trochantin", by the earlier writers. 



The trochanter. 



The trochanter, tr (of all figures) is always more closely connected 

 with the femur fe , than with the coxa, and is considered by some 

 investigators as a ''constricted-off" portion of the femur. In the 

 Phasmids it is very closely united with the femur, and in the m eta- 

 thorax of the grasshopper (Fig. 16) it is immovably united with the 

 femur, though demarked from it by a distinct suture. It is doubtless 

 due to the fact of its close union with the femur in the metathorax 

 of the grasshopper, that the trochanter of the metathoracic leg was 

 overlooked by the earlier writers, who designated the true coxa ex 



