Subfamily Nemobiinae - Ground Crickets

Pygmy Field Crickets

Moved from family Trigonidiidae at BugGuide on 31 January 2008. Placement in family Gryllidae follows the classification used in the Orthoptera Species File here; see Taxonomy Proposals forum topic on "Orthoptera" here.

"Nemobiinae are characterised by the presence of prominent bristles on the vertex and frons and the absence of dorsal spines on the hind basitarsus." -Sam W. Heads

Most similar are Field Crickets and kin of subfamily Gryllinae, and Bush Crickets or "Trigs" of subfamily Trigonidiinae.

Ground Crickets are small (adults under 1/2 inch long), have 3 or usually 4 pairs of long movable pairs of spines above the tip (not counting longer spurs at tip). These Crickets have the body, notably the thorax, covered in bristles. The ovipositor varies from long straight and needle-like to short, curved up and sword-like.

Field Crickets are much larger (adults, except Striped Crickets, usually over 1/2 inch long), have 4 or usually more pairs of non-movable spines above the tip of the hind femur (not counting longer movable spurs at tip). They may be somewhat fuzzy looking, but are not covered with bristles. The ovipositor is long, slender, needle-like, and slightly but distinctly swollen at the tip. The face is wide, with the antennae far apart at the base.

Trigs are about the same size, but more slender with a smaller more angular head, distinctly narrower thorax, longer legs, and they live in vegetation instead of on the ground (most Ground and Field Crickets are ground dwellers). They have three pairs of long movable spines on the hind tibiae, are not as bristly. The ovipositor is relatively short, curves up, and is rather sword-like. The maxillary palpi (appendages on the side of the mouth) are distinctly more swollen and distinctly club-like (also swollen, but less so in Field and Ground Crickets).

Other groups of Crickets differ distinctly in shape, may have scaly bodies, and/or the hind tibiae have rows of many bristles between or instead of shorter spines.

Anomalous Crickets, Subfamily Pentacentrinae, with only one North American species in Texas and Oklahoma is similar to the Trigs in having three pairs of tibial spurs and long slender legs, but a wide face and thorax more like Ground Crickets. These have a long slender ovipositor more like Field Crickets and some Ground Crickets. They are pale yellowish in color with blackish eyes, antenna bases, and ovipositor tip and tegmina darker than the rest of body and legs. They might be confused with Allonemobius, but that genus has four pairs of tibial spurs, shorter stockier legs, and is not colored in the same way.

Species of Ground Crickets are often varied in appearance within the same species and different species can look very similar. The easiest way to tell species apart involve knowing when and where they came from (which narrows the choices), being able to examine the specimen in hand for various details of structure, and hearing the songs they make. Since the last two are usually not possible from a photograph posted to BugGuide, it is necessarily the case that identifications are often tentative and really just educated guesses. Sometimes it is even difficult to tell to which genus a specimen belongs.

To tell which genus these belong to, it helps (when possible) to have views of the under side as well as the upper side, and if possible these should show the hind legs clearly. In females a clear view of the ovipositor (the sword-like egg laying appendage) at the tip of the abdomen is often a great help. Also, it helps to note the size (and be clear what is being measured - usually length is given as the measure of the face to the end of the abdomen, not including all the appendages such as legs, antennae, cerci, and ovipositors).

Allonemobius - 11 species

Eunemobius - 3 species

Neonemobius - 6 species

Pictonemobius - 4 species, FL and adjoining states

Hygronemobius - 1 species, FL

classification plus common names reference, synonyms, included taxa, and literature citations (Orthoptera Species File)