Glossary and parts
This is a glossary of Water Bug parts especially used in the identification key.
Abdomen. Primarily used for breathing, digestion, excretion and reproduction, it is the third main body function after the head and thorax and underneath the wings and hemelytra.
Abdominal teeth. These can be found on those underside of the abdomen near the rear end and are used to identify male Gerris odontogaster.
Antennae. There are two of these attached at the top of the head and are used for sensing their environment. In water bugs Nepamorpha have short ones hidden under the head and Gerramorpha have larger more visible ones usually longer than the head
Bristle. These are short stiff hairs that can appear on an insects body and can functional and used as sensors, for cleaning, etc.
Claspers. A pair of appendages at the end and under the abdomen that are used to hold the female in place during copulation.
Clavus. The oblong scleritis at the base of the inferior margin of the hemelytra. This is used in the identification of Sigara sp.
Claw. The claws are the final segment of the leg after the tarsi. The comparative length is used in some identification
Connexivum. This is the edge of the abdomen that contains the connection between the tergite and sternite. For Velia sp. this creates two raised ridges and has different colourations.
Coxae. These are the first leg segments that are attached to the body. In Gerris costae these can be visible from above.
Eyes. All water bugs have 2 compound eyes located on the head.
Face. The area between the base of the antennae, the mouthparts and between the eyes. In Sigara sp. this feature could have facial depressions or a keel.
Femur. The thickest most muscular part of the leg attached to the coxa.
Forewing. The pair of wings that are closest to the head.
Head. Of the three main body parts (Head, thorax and abdomen) the head is the front segment.
Hemelytra. This is the bugs outer wing casing. It is usually leathery at the base (rather than a hard beetle case) with a softer membrane near the rear end flaps over the two so that it forms an X on the upper surface.
Keel. A projecting ridge that resembles a "ship's keel". For Arctocorixa sp. this is a raised line on the pronotum.
Legs. Water bugs always have six legs joined to the body by the coxae and each made up of a femur, tibia and tarsus. They can be modified to hold prey, walk on water or swim faster and these modifications are used in the identification.
Membrane. The membrane is the end of the wing case that is leathery but much softer than the harder base. It also frequently opens out at the tip that then flaps over the other wing case.
Ocelli. These are simple eyes that are used for movement detection and positioned on top of the head between the compount eyes in Hebrus.sp
Palae. These are modified tarsi. In corixidae males, the modifications to the front foot are are flattened and scooped like a shovel in order to enhance propulsion and swimming. There are pegs on the inner side of these that can be used for identification of species.
Pronotum. This is the plate like structure that covers all or some of the thorax. In Microvelia sp the thorax has three plates, including the Prontum but also the mesonotum and metanotum.
Rostrum. A beak like stabbing mouthpart that all bugs possess. This is very prominent in most aquatic bugs but in corixidae this forms part of the face.
Scutellum. The central plate at the back of the pronotum and normally between the bases of the hemelytra. It is usually triangular, but sometimes parallel sided and enlarged. It totally covers the wings in some species.
Strigil. A black, toothed plate on the sixth abdominal segment on most male corixidae. It is thought to be concerned with grasping during mating.
Spine like tail. This is situated at the rear end of Water Scorpion and Water Stick Insect but is actually a siphon or breathing tube allowing the bug to collect oxygen from the surface.
Swimming hairs. These are present on the hind legs of species that appear to aid swimming. They are used as an identification feature in some corixid's and can be dark or pale. The can also disguise the colour of the leg parts and need to be moved out of the way when identifying.
Thorax. The part of the body that lies between the head and the abdomen. It has three parts prothorax, mesothorax and metathorax.
Tibia. The leg segment between the tarsus and femur.
Tarsus T1, T2, T3, T4 and T5. These are the end segments of the leg, what you could call the "foot". There are a maximum of five sgments that make this up and they are numbered from the leg which is T1 to the final segment which is T5.
Tubercule. Small raised "lumps". These can be scattered across the body surface however for Gerris gibbifer this is just one raised lump between the mid legs on the underside. The colouration can change and be lighter too.
Vertex. This is the upper surface of the head not including the compound eyes.
Waterproof hairs. These are usually silvery hairs that are found on surface bugs and can trap air. They can aid bugs bouyancy on the surface or as an air source. Whether they are present or the shape of patches is an identification feature and they can be more prominent and visible when the bugs are dry.
Wings. The wings of bugs are transparent, veined and found under the wing cases on top of the abdomen. Not all bugs or life stages have wings and in most species there can be winged and non winged versions of the bugs that then need to be identified using different features.
Xiphus. This is a triangular part between the front and mid coxae. In corixidae this can be pointed or blunt.
Abdomen. Primarily used for breathing, digestion, excretion and reproduction, it is the third main body function after the head and thorax and underneath the wings and hemelytra.
Abdominal teeth. These can be found on those underside of the abdomen near the rear end and are used to identify male Gerris odontogaster.
Antennae. There are two of these attached at the top of the head and are used for sensing their environment. In water bugs Nepamorpha have short ones hidden under the head and Gerramorpha have larger more visible ones usually longer than the head
Bristle. These are short stiff hairs that can appear on an insects body and can functional and used as sensors, for cleaning, etc.
Claspers. A pair of appendages at the end and under the abdomen that are used to hold the female in place during copulation.
Clavus. The oblong scleritis at the base of the inferior margin of the hemelytra. This is used in the identification of Sigara sp.
Claw. The claws are the final segment of the leg after the tarsi. The comparative length is used in some identification
Connexivum. This is the edge of the abdomen that contains the connection between the tergite and sternite. For Velia sp. this creates two raised ridges and has different colourations.
Coxae. These are the first leg segments that are attached to the body. In Gerris costae these can be visible from above.
Eyes. All water bugs have 2 compound eyes located on the head.
Face. The area between the base of the antennae, the mouthparts and between the eyes. In Sigara sp. this feature could have facial depressions or a keel.
Femur. The thickest most muscular part of the leg attached to the coxa.
Forewing. The pair of wings that are closest to the head.
Head. Of the three main body parts (Head, thorax and abdomen) the head is the front segment.
Hemelytra. This is the bugs outer wing casing. It is usually leathery at the base (rather than a hard beetle case) with a softer membrane near the rear end flaps over the two so that it forms an X on the upper surface.
Keel. A projecting ridge that resembles a "ship's keel". For Arctocorixa sp. this is a raised line on the pronotum.
Legs. Water bugs always have six legs joined to the body by the coxae and each made up of a femur, tibia and tarsus. They can be modified to hold prey, walk on water or swim faster and these modifications are used in the identification.
Membrane. The membrane is the end of the wing case that is leathery but much softer than the harder base. It also frequently opens out at the tip that then flaps over the other wing case.
Ocelli. These are simple eyes that are used for movement detection and positioned on top of the head between the compount eyes in Hebrus.sp
Palae. These are modified tarsi. In corixidae males, the modifications to the front foot are are flattened and scooped like a shovel in order to enhance propulsion and swimming. There are pegs on the inner side of these that can be used for identification of species.
Pronotum. This is the plate like structure that covers all or some of the thorax. In Microvelia sp the thorax has three plates, including the Prontum but also the mesonotum and metanotum.
Rostrum. A beak like stabbing mouthpart that all bugs possess. This is very prominent in most aquatic bugs but in corixidae this forms part of the face.
Scutellum. The central plate at the back of the pronotum and normally between the bases of the hemelytra. It is usually triangular, but sometimes parallel sided and enlarged. It totally covers the wings in some species.
Strigil. A black, toothed plate on the sixth abdominal segment on most male corixidae. It is thought to be concerned with grasping during mating.
Spine like tail. This is situated at the rear end of Water Scorpion and Water Stick Insect but is actually a siphon or breathing tube allowing the bug to collect oxygen from the surface.
Swimming hairs. These are present on the hind legs of species that appear to aid swimming. They are used as an identification feature in some corixid's and can be dark or pale. The can also disguise the colour of the leg parts and need to be moved out of the way when identifying.
Thorax. The part of the body that lies between the head and the abdomen. It has three parts prothorax, mesothorax and metathorax.
Tibia. The leg segment between the tarsus and femur.
Tarsus T1, T2, T3, T4 and T5. These are the end segments of the leg, what you could call the "foot". There are a maximum of five sgments that make this up and they are numbered from the leg which is T1 to the final segment which is T5.
Tubercule. Small raised "lumps". These can be scattered across the body surface however for Gerris gibbifer this is just one raised lump between the mid legs on the underside. The colouration can change and be lighter too.
Vertex. This is the upper surface of the head not including the compound eyes.
Waterproof hairs. These are usually silvery hairs that are found on surface bugs and can trap air. They can aid bugs bouyancy on the surface or as an air source. Whether they are present or the shape of patches is an identification feature and they can be more prominent and visible when the bugs are dry.
Wings. The wings of bugs are transparent, veined and found under the wing cases on top of the abdomen. Not all bugs or life stages have wings and in most species there can be winged and non winged versions of the bugs that then need to be identified using different features.
Xiphus. This is a triangular part between the front and mid coxae. In corixidae this can be pointed or blunt.
