70 Invasive Stink Bugs and Related Species (Pentatomoidea)
Myrocheini; and Paramecocoris Stål, as a replacement name for the preoccupied genus Paramecus
Fieber, usually is placed in the Caystrini. The remaining Australian genera often have been included in
this tribe, but Gross (1975b) placed them in their own group (the Menestheus group), and this will be
discussed under that heading. At present, this tribe contains eight genera and 19 species (Table 2.3), but
this is likely to change drastically in the near future.
Aeptus species tend to be small to medium in size, elongate to pear-shaped (Figures 2.12B, 2.28B). The
juga extend well beyond the apex of the tylus, the lateral margins are sharply edged and not reflexed, and
the length of the head is usually longer than the median length of the pronotum. The eyes and ocelli are
reduced. The first antennal segment does not reach the apex of the head, and the antenniferous tubercles
are small, not visible from above. The rostrum reaches to or beyond the hind coxae, the second segment
is longer than the last two segments together. The prosternum is bordered by a pair of erect lobes in front
of the fore coxae. The hemelytra, in Aeptus species, are usually brachypterous with the coria somewhat
squarish; the scutellum is more spatulate, reaching beyond the coria (Figures 2.12B, 2.28B). The thoracic
sterna are sulcate without median carinae; the scent efferent system and evaporatoria are quite reduced.
The abdominal venter is unarmed basally. The male pygophore is robust with the apical margin deeply
insinuated, and the ventral surface is depressed medially. The parameres are long and slender with numer-
ous hairs apically. In the female, the spermathecal bulb is simple, ball-shaped, and lacks diverticula.
Linnavuori (1982) indicated that this tribe was probably related to Dymantis (now considered a member
of the Myrocheini), and speculated that Aeptus might belong in the Myrocheini (see Section 2.2.10.7.29).
He further indicated that its members occur on grasses in mesic and moist habitats. Our initial studies
indicate that one of a couple scenarios may be possible, depending on whether one is a lumper or a split-
ter. On one hand, it appears that the Australian genera often placed in this tribe may not be closely related
to the type genus Aeptus and may need a new tribe of their own. On the other hand, the Australian “aep-
tine” genera show a marked resemblance to African genera now placed in the tribe Diploxyini, which in
turn may be con-tribal with Aeptus. Finally, there are at least another three genera currently placed in
the Carpocorini that may belong with these genera. Two of these genera occur in India (Bonacialus and
Gulielmus), and one is South American in distribution (Poriptus Stål). All three have the mesosternum
distinctly sulcate without a medial carina, which should preclude their membership in the Carpocorini;
they are also elongate, slender with the juga longer than the tylus, and at least Poriptus is known to feed
on grasses (similar to other “aeptines” whose host plants are known).
2.2.10.7.4 Aeschrocorini Distant, 1902
Distant (1902) originally proposed the Aeschrocoraria to hold two genera, Aeschrocoris Bergroth and
Scylax Distant. This tribe was not mentioned again until Cachan (1952) added Aeschrus Spinola and his
new genus, Chraesus. This tribe is still relatively small, tentatively containing eight genera (Oriental
Region: Aeschrocoris [Figure 2.28C], Scylax; Afrotropical Region: Aeschrus, Chraesus, Geomorpha
Bergroth, Risbecella Schouteden, Tyom a Spinola [Figure 2.19C], and Tyom ana Miller) and 20 species
(Table 2.3). Most of the included genera are dark brown to blackish with a strongly gibbose body vari-
ously outfitted with tubercles, spines, and/or other elevations. The head is somewhat elongate, and the
juga may or may not extend beyond the apex of the tylus. The thoracic sterna are sulcate, usually lacking
a medial carina. The ostiolar rugae are small and auriculate; and the evaporative area is also reduced.
The scutellum is spatulate to subtriangular and, in some cases, the coria do not reach the apex of the scu-
tellum. The hemelytral membranes are often reticulate (except in Tyom ana). The first visible abdominal
sternite usually has a deep medial depression, which often is delimited by an elevated lobe on each side.
The position of the spiracles is unusual in that they are situated more lateral than in most pentatomines,
located just below the connexival margin and with a distinct tubercle between each pair of spiracles
(a similar condition is found in the South American genus Caonabo Rolston, but that genus has the tho-
racic sterna carinate medially).
The male pygophore usually has a small genital opening; the parameres are long and slender,
sometimes enlarged apically, and sometimes bilobed. According to Linnavuori (1982), the penis-
filum in Tyom ana is of the usual pentatomine type, but in Aeschrus, it is quite distinctive with the
theca broad and flattened, and the vesica is rather long and coiled. The female spermathecal bulb