I thought I would share the specimen with you and took photos of two Nepidae to give a sense of scale: an unidentified Laccotrephes sp. from Arabia, and a smaller native Nepa cinerea specimen from the British Collection.

Left, unidentified 'toe biter' (Belostomatidae); Middle, Laccotrephes sp. (Nepidae) collected in Arabia; Right, Nepa cinerea (Nepidae) a British specimen. © The Natural History Museum

As you can see, the Belostomatid dwarfs them both! My supervisor tells me that the biggest Hemiptera are the Belostomatidae and some Pomponia cicada species. Our water scorpion is a relatively small member of the Nepidae, but the unidentified Arabian specimen looks remarkably similar.  I chose Laccotrephes sp. because it is part of the accessions, a veritable treasure trove of unidentified speciemens, and because it has nice patterns on the limbs.

Whilst looking for specimens to photograph, I noticed that the majority of siphons (the abodominal air tubes) of the Nepidae had separated into their two component tubes.