Revision of the Notonectide. 395 
2 (1) Tibi postice tarsique postici non ciliati ; venter 
nec carinatus nec ciliatus; rostrum 5-segmentatum ; 
oculi parvi, vix conspicul : - . PLEINA 
Subfam. NOTONECTIN 2A. 
A Oculi ad basin non contigui; femora postica non 
attingentia hemielytrorum apicem. 
a (b) Pronotum non transversissimum ; als adsunt, wre 
hemielytrorum distincte. 
1 (2) Antennarum segmentum ultimum penultimo multo 
brevius ; tarsi postici unguiculis destituti. 
Notonecta, L. 
2 (1) Antennarum segmentum ultimum penultimo multo 
longius ; tarsi postici unguiculis instructi. 
Anisops, Spin. 
> (a) Pronotum transversissimum ; antennarum segmenta 
ultimum penultimumque subzqualia; tarsi postici 
unguiculis longis instructi. 
1 (2) Hemielytrorum arez distincte ; ale adsunt ; tarsi 
intermedi bisegmentati . : Enithares, Spin. 
2 (1) Hemielytrorum arez null seu subobsoletz ; ale 
desunt; tarsi intermedii unisegmentati. 
Martarega, B. White. 
A A Oculi ad basin contigui ; hemielytrorum are null 
seu indistinctz ; ale nulle ; pronotum transver- 
sissimum, 
1 (2) Femora postica ultra hemielytrorum apicem extensa; 
antennarum segmentum ultimum penultimo multo 
longius ; tarsi postici unguiculis brevissimis in- 
structi . 5 : : . Antipalocoris, Scott. 
2 (1) Femora postica non attingentia hemielytrorum apicem; 
antennarum segmentum ultimum penultimo multo 
brevius; (? tarsi postici unguiculis destituti). 
Signoretiella, Berg. 
I have seen no satisfactory account of the structure of 
the head in this family; and as it is very obscure in the 
mature imago, and can be worked out only from a com- 
parative study of the larval stages, novel but provisional 
terms have been employed in describing it. That por- 
tion of the head which is apparent from a dorsal aspect 
is named the notocephalon ; it 1s more or less constricted 
close to the base, this constriction, here termed the 
