82 Invasive Stink Bugs and Related Species (Pentatomoidea)
2.2.10.7.18 Diemeniini Kirkaldy, 1909
Bergroth (1905) first proposed the Platycoraria, based on the genus Platycoris Guérin-Méneville, for this
group. There was some confusion, however, surrounding the publication dates of Guérin-Méneville’s
paper. In 1831, two of the plates (the text was not published until 1838) were published out of order, which
affected the type species for Platycoris (see Dupuis 1952 for more details). The result is that Platycoris is
actually a member of the Halyini, not the Diemeniini; Bergroth’s Platycoraria is based on a misidentified
type genus and, therefore, a junior synonym of Halyini. Kirkaldy (1909) proposed Diemeniini to replace
Platycorini, based on the genus Diemenia Spinola.
This tribe includes 14 genera, of which 12 are endemic to Australia; Oncocoris Mayr (Figure 2.21C)
is mostly distributed in Australia, but a few species are found in New Guinea and the Solomon Islands;^
Caridophthalmus Assmann (Figures 2.12D, 2.21B) also has species in Australia, but its center of diver-
sity is Papua New Guinea. There are about 55 described species in the tribe (Table 2.3). This group
has been associated with the Halyini by Dallas (1851) and Stål (1876). As might be expected, due to
the presence of abdominal stridulatory structures in both tribes, the Diemeniini occasionally has been
lumped with the Mecideini. Gross (1975b) indicated that he found, especially in the structure of the male
genitalia, that the Diemeniini may have some relationship with the Halyini, but he further stated that the
Diemeniini is not identical with the Halyini, and that both were distinct from the Mecideini.
Members of this tribe are small to medium in size (5-14 mm), and exhibit several different forms and col-
ors; in fact, the variability might make one question whether they all belong in the same tribe or not (Figures
2.21B, 2.29I). The single, unifying character is that all included genera have a distinct, lunately shaped,
stridulatory area located on each side of the abdominal venter. Only one other pentatomid genus (Mecidea,
presently in the Mecideini) has a similar stridulatory area, but the included species are quite elongate, slen-
der, and pale, and they occur in dry, arid areas outside of the Australian region. There is another genus
(Neomazium, presently placed in the Carpocorini) that has a stridulatory mechanism on the abdominal ven-
ter, but this mechanism is placed along the margins of the abdomen and is not homologous with that found
in the Diemeniini. The antennae may be four- or five-segmented. Often, the juga are produced beyond the
tylus, and the lateral margins are usually reflexed, often with a small process in front of each eye. According
to Gross (1975b), the male genitalia are quite variable with the parameres either Y-shaped (Diemenia and
Caridophthalmus), thin and elongate (Aplerotus Dallas), or flattened or plate-like (Kalkadoona Distant and
Oncocoris). The spermathecal bulb is simple, ball-shaped, without finger-like diverticula.
Both Kalkadoona and Oncocoris (Figure 2.21C) have the prosternum, mesosternum, and metaster-
num medially carinate; and the ostiolar rugae are relatively elongate and straight. As mentioned above,
Caridophthalmus (Figures 2.12D, 2.21B) is the only diemeniine genus with greater diversity outside of
Australia (but most species remain undescribed). The species also differ significantly from the Australian
members of this tribe. The stridulatory ridges in Caridophthalmus are more widely spaced and some-
what obtuse. In fact, one might question whether they are actually involved in stridulation except that
there are stridulatory pegs on the inner surface of the hind femora. Additionally, members of this genus
have the surface of the head distinctly horizontal, facing forward, and the dorsal surface is armed with
various distinct spines (Figures 2.12D, 2.21B). It is possible that once a thorough phylogenetic analysis
is completed, this genus will be placed in its own tribe. There are some general similarities between this
genus and the newly described Pentamyrmex Rider and Brailovsky, an ant-mimic genus for which a new
tribe, Pentamyrmecini, has been erected (see discussion under Pentamyrmecini, Section 2.2.10.7.33).
Relatively recent revisions have been provided for Diemenia (Ahmad and Kamaluddin 1989a) and
Oncocoris (McDonald and Edwards 1978).
2.2.10.7.19 Diplostirini Distant, 1902
This is a small tribe, containing two monotypic genera (Table 2.3); they are confined to India and
the Orient. Distant (1902) originally based this tribe on the distinctly concave posterior margin of the
pronotum (conversely, the basal margin of the scutellum is distinctly convex). In fact, the two included
genera have little in common, except for the general elongate shape, and there is little doubt that they are
not closely related. The only species of the genus Diplostira Dallas, D. valida Dallas (Figure 2.29J),
is quite large (body length about 25 mm) and has the base of the abdominal venter obtusely spined;