1916] Thoracic and Cervical Sclerites of Insects 61 



Packard, '80, in his figures of Corydalis shows the episternum 

 extending from the coxa to the wing process. He also includes 

 the trochantin and precoxal bridge as part of the episternum. 

 Crampton, '09, considered the episternum as extending from 

 the coxal process to the pleural wing process. Snodgrass, '09, 

 regarded the anepisternum (upper portion of episternum) in 

 Corydalis, as the entire episternum (Fig. 10, esp). The epister- 

 num, however, extends from the coxal process to the pleural 

 wing process, as is very clearly illustrated in Periplaneta. Most 

 writers fail to take this fact into consideration and consequently 

 the resulting misinterpretation and confusion. 



In Dictyophora and Dissosteira the sternum, episternum and 

 precoxale are closely united. This condition is more or less 

 pronounced in the various insect orders. In the pro-, meso- and 

 metathorax of Forficula (Fig. 8, pCi, pco, pCs) and in the meso- 

 thorax of Grylliis, (Fig. 7, PC2) the precoxale becomes split up 

 and is not fused with the sternum. In the prothorax of Gryllus, 

 however, the episternum, precoxale and sternum are closely 

 united (Fig. 7, pci, esi, vsi). 



Audouin, '24, termed the anterior plate of the pleuron the 

 episternum. This term is still in use and accepted by everyone. 

 When the episternum is subdivided it is necessary to use other 

 terms to designate the subdivisions, as previously discussed 

 in the case of Tabanus, Mantispa, Chrysopa, etc. Burmeister, 

 '32, termed the episternum the " parapleura. " Packard, '80, 

 called the upper portion the sur- and supra-episternum and the 

 lower portion the sub- and infra-episternum, using the former 

 and also the latter terms interchangeably. Packard studied 

 a large number of insects and used the terms, "pleurites" and 

 "sternites, " in his terminology. Although his homologies of 

 the sclerites are incorrect in many cases, his ternimology has 

 many good points. His work on the whole is very good and 

 has not been accorded sufficient attention. Amans, '85, 

 termed the episternum the " antepleuron. " Jordan, '02, applied 

 the terms "para-sternum" and "episternum" to the anepister- 

 num (upper portion of episternum). The term "parasternum" 

 he also applies to the basalar plate. The sternopleurite (lower 

 portion of episternum fused with a part of the sternum), he 

 terms " hyposternum. " He confuses his own terms by mis- 

 interpreting the sclerites in different papilionids. In Forficula, 



