Insects' mouthparts

[SU_reptile]

Hi everyone. I am preparing comparison of mouthparts and I have some doubts.
I can't find the role of labial palps in orthopteroid (chewing) and sucking type and the role of maxillary palps in the licking one.
Moreover, I have two books that bear opposite opinions on origin of praementum, mentum, submentum and hypopharynx. In the first one there is written that praementum only bears glossae, paraglossae and labial palps, mentum is homologous to stipes, submentum homologous to cardo and hypopharynx arose from merging the sterna of labial segments. However the second one claims that praementum is homologous to stipes, mentum is homologous to cardo and submentum is that merged sternum.
Do you have any idea which consensus is closer to the truth