65 
designates the fusion product of sternites bs and fs as the sternum, 
likewise including the anterior of the two cervical sternites cs, under 
this designation. Berlese, 1906—1909, applies the term sternellum to 
practically all of the sternites (and to the meron in addition) in dif- 
ferent insects. Hopkins 1909, applies the terms presternum, sternum, 
sternellum, and poststernellum to four secondarily-marked-off regions in 
the fusion product of bs and fs, in Dendroctonus. Snodgrass, 1909b, 
applies the designation sternellum to the sternite ss, and usually terms 
the sternite bs, the sternum, while the sclerites which he designates as the 
presternum include the lateral and ventral intersegmentals, together 
with sclerites [st (or /st united with /pl) and the anterior portion of bs. 
It would be possible to apply MacLeay’s terms to the first four 
sternites cs, is, bs, and fs (fig. 1) or to the sternites 7s, bs, fs, and ss, this 
however, would merely add to the already sufficiently disconcerting 
confusion in applying these terms, so that it is preferable to discard 
them entirely (especially since the term sternum should not be applied 
to both the entire sternum, and one of its subdivisions as well) and apply 
purely descriptive terms to the sternites (which are more than four — 
the number postulated by Macleay). 
The two cervical sternites cs are either detached portions 
(“derivatives”) of the presternite és, or owe their origin to the rubbing 
of the head upon the folds of the neck. They are present only in the 
cervical region. Only one is shown in the figure. 
The presternite és is present as a distinct plate in front of all 
three segments of Capnia and Leuctra (Plecoptera), but is usually 
present in front of the prothorax alone in other insects, such as the 
Dermaptera, Embiidae, etc. | 
The basisternite bs (like the basisphenoid of the skull) forms the 
lower portion of the sternum, while its two wings, the laterosternite Ist 
one on either side) extend upward into the pleural region, and may 
form detached plates, as in the Dermaptera. The plate /pl of the pleural 
region and (st of the sternal region become united in a single detached 
plate in the prothorax of the Blattidae, and these two sclerites usually 
unite in other insects, to form a pre-coxal bridge, connecting the sternal 
and pleural regions. A narrow posterior marginal region ac, the ante- 
coxale, is marked off in the posterior region of the plate Ist (in the 
metathorax of the earwig Echinosoma) or in the pre-coxal bridge, in the 
prothorax of the Blattidae. 
The furcasternite fs always bears the furca. It is called the 
antecoxal piece in Coleoptera. The postfurcasternite, s is a well 
developed, detached plate in all three thoracic segments of such insects 
as Capnia; but unites with the other sternites, in higher insects. 
Zoolog. Anzeiger. Bd. XLIV. 9) 
