60 AfinaJs Entomological Society of America [Vol. IX, 



resulted in a confused terminology. Packard, '80, termed the 

 upper region of the episternum, the " sur- and supra-episternum.' 

 Hammond, '81, called it the "parapteron. " Brauer, '82, 

 and several other workers called it the episternum, while 

 Snodgrass, '09, included a portion of the pteropleurite (upper 

 region of the epimeron) and the upper region of the episternum 

 together, as the episternum. Lowne, '90, termed it the lateral 

 plate of the " mesosternum, " Petri, '99, the " antepleura, " 

 borrowing Amans '85, term for the entire episternum, (ante- 

 pleuron). Osten-Sacken, '84, termed it the " mesopleura, " 

 which is inappropriate, because it is not the entire mesopleuron. 

 Crampton, '08, called it the " hyper-episternum " and later, 

 Crampton, '09, the "anepisternum. " I shall adopt for it 

 the term anepisternum. In Chrysopa, Mantispa, etc., (Fig. 13, 

 esp, ptp) the terms anepisternum and also pteropleurite have 

 been used for the upper portions of the episternum and epi- 

 meron, since these regions are homologous with those found in 

 Diptera (Fig. 11, esp, ptp). 



In the meso- and metathorax of Periplaneta the episternum 

 consists of one sclerite, which is fused with the precoxal bridge or 

 precoxale (Crampton, '14) (Fig. 3, es, ess). The trochantin is 

 partially attached to the episternum in the prothorax (Fig, 

 3, tni). The episternum, together with the epimeron form a 

 deep hollow pocket by the infolding of the integument, which 

 bears internally the pleural process. The episternum in the 

 earwig consists of a single sclerite (Fig. 8, esi). 



In Capnia the prothoracic episternum consists of one piece 

 (Fig. 4, esi). The meso- and metathoracic episternum is divided 

 by a suture into an upper and lower portion (Fig. 4, esp, pltn) 

 giving a condition comparable to that found in Chrysopa 

 (Fig. 13, esp, pltn). Here also we have the beginning of a 

 condition similar to that found in Tahanus (Fig. 11, esp, stp). 

 The fusion of the sternum with the lower portion of the epister- 

 num, precoxale, etc., suggests the probable formation of the 

 stern opleurite (Figs. 1, 2 and 11, stp). 



In Corydalis the condition of the episternum in the meso- 

 thorax is similar to that found in Capnia and Tabanus. (Fig. 

 10, esp, stp). The suture dividing the episternum becomes 

 more pronounced and takes the form of a deep cleft. The 

 precoxale, sternum and episternum become more closely fused. 



