66 
The spinasternite ss bears the spina, or unpaired internal apo- 
physis. It is present in many Orthoptera, in the prothoracic region, but 
is usually small and indistinct, and in some insects, fuses with the ster- 
nite in front of it — in others, it fuses with the sternite behind it (e. g 
in Corydalis). 
There is considerable doubt as to whether the spinasternite is the 
first sternite of the segment following it, or the last sternite of the one 
in front of it, since it is united with the segment behind it, in the meso- 
thorax of such insects as Corydalis; and even in the Orthoptera, it is 
much nearer to the segment behind it than to the one in front. The 
musculature would admit of either interpretation, but since it is usually 
attributed to the segment in front it will be treated as the posterior most 
sternite in the present paper. The terminology here applied to the ster- 
nites, being purely descriptive, would apply equally well in either case. 
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