Higher Systematics of the Pentatomoidea 71
in Tyom a is elongate basally, rounded apically, with three medium-length, somewhat robust, diver-
ticula arising from near the apex of the bulb; the spermathecal duct below the proximal flange is
not swollen.
We have examined specimens of Aeschrocoris, Aeschrus, Geomorpha, Risbecella, Scylax, and Tyom a.
At present, we believe that Aeschrocoris, Geomorpha, and Tyom a all belong to a single tribe. Aeschrus,
as noted by Linnavuori (1982), is quite different, and may not belong in this tribe. It looks superficially
similar in general appearance to the members of this tribe, but the spiracles are not located laterally, the
pronotum has a distinct rounded flap extending posteriorly on each side over the base of each corium,
and the scutellum is expanded laterally beyond the apex of the frenum on each side, also covering part
of each corium. It appears that Chraesus and Risbecella are also members of this tribe; Tyom ana is
highly similar to and is probably a junior synonym of Risbecella. We also have serious doubts about
including Scylax in this tribe. In Scylax, the characters of the head, sternum, and scutellum are similar to
those described above for Aeschrus, but the general habitus of the animal is markedly different (dorsum
weakly convex, integument relatively smooth); the hemelytral membrane is not reticulate; the base of the
abdominal venter is neither grooved nor spinose; the spiracles are in a more typical position, not located
laterad; and there are no tubercles between the spiracles.
Linnavuori (1982) indicated that there were similarities between this group and the Diploxys group
(= Diploxyini); that is, they have a similar body form, humeral spines on the pronotum, apical spines on
the femora, posterolateral angles of the last abdominal segment often spinose, and a similar structure of
the thoracic sterna. Hassan et al. (2016) provided a review of the Indian species of Aeschrocoris.
Other than a few host plant records, there is little biological information available for members of
this tribe. Linnavuori (1982) recorded Aeschrus inaequalis Spinola from Croton zambesicus Müller
Argoviensis (Euphorbiaceae) and Tyoma verrucosa Montandon from eggplant (Solanaceae). Also, Tyom a
cryptorhyncha (Germar) has been recorded from cowpea (Fabaceae) (Phelps and Oosthuizen 1958).
2.2.10.7.5 Agaeini Cachan, 1952
This is a monotypic tribe, containing only the genus Agaeus Dallas (Figure 2.28D). Members of this
tribe occur in Madagascar, Africa, through the Indian subcontinent, China, into southeast Asia. Recently,
Agaeus has been divided into two genera with the erection of a new genus, Jostenicoris Arnold for the
Afrotropical species (Arnold 2011a). However, as Arnold (2011a) failed to mention any single differen-
tiating character for his new genus, Jostenicoris is unavailable (Kment 2013). Agaeus currently contains
eleven species (Table 2.3), and it has had a chaotic taxonomic history. Stål (1865) treated this genus
between Afrania Stål and Stenozygum Fieber, both of which are now in the Strachiini, thus indicating
that Stål may have believed Agaeus also belonged in the Strachiini. Cachan (1952) erected the Agaeini
based on his study of Madagascan material. Linnavuori (1982) included this genus in the Eurydemini
(= Strachiini). More recently, Azim (2002) placed this genus in the Halyini, a placement supported by
Memon et al.’s (2011) phylogenetic study of the South Asian halyines, but their methodology has been
criticized (Barão et al. 2012).
Members of this genus are medium to relatively large in size; they are generally dark (sometimes red-
dish) in coloration with pale yellowish to orangish stripes or mottled areas forming distinct patterns on
the dorsum (Figure 2.28D). The head is somewhat elongate triangular with the lateral margins narrowly
reflexed; the tylus is longer than the juga. The rostrum extends well onto the abdomen; the abdominal
venter may be shallowly to distinctly sulcate medially. The anterolateral pronotal margins are distinctly
reflexed. The thoracic sterna are not sulcate, the mesosternum has a medial carina, and the metasternum
is flattened. The ostiole is quite small, lying mesad between the middle leg and hind leg; the ostiolar
rugae are reduced to a short, rod-like, shiny area, each narrowly surrounded by the much reduced,
V-shaped evaporatoria (very similar to that seen in the Strachiini). The scutellum is triangular in shape
with the coria reaching well beyond the scutellar apex. The abdominal venter is unarmed basally. The
male parameres are rather robust, hatchet-shaped, often with a large, distinct tooth near the base of the
parameral stem. The female basal plates in some species are relatively small, well separated, with a large
medial plate between them.
The elongate head with the tylus somewhat longer than the juga, and the medially sulcate abdominal
venter might ally this genus with the Halyini. The much reduced ostiolar apparatus could indicate a