46 Invasive Stink Bugs and Related Species (Pentatomoidea)
but not all, of the dorsum but usually reaching to near the apex of the abdomen; it is much shorter and
more triangular in L. grossi. The margins of the head, pronotum, and basal areas of the coria, in both
species, are laminately produced, giving the insect the appearance of a small tortoise beetle or scale. The
pronotum is relatively large with the anterior angles reaching beyond the anterior margin of the compound
eyes. The ocelli are quite small and widely separated. The antennae are relatively short, four-segmented.
They have two-segmented tarsi, which has been used to link them with the Acanthosomatidae. Similarly,
the females have a pair of small disclike organs located on abdominal sternite VI just anterior to and
laterad of the external genitalia; again, these have been considered to be homologous to the Pendergrast’s
organs in the Acanthosomatidae; China (1955) speculated that they may help specimens adhere to the
substrate. The two species possess a pair of small, transversely arrayed trichobothria (initial studies by
China 1955 indicated that there was only a single trichobothrium on each segment; this was later cor-
rected by China 1963) with the ental trichobothrium of each pair in line with the spiracular line. The
female spermathecal duct lacks a dilation and a sclerotized rod; the spermathecal bulb is ball-shaped,
without diverticula; Schuh and Slater (1995) indicated that L. haustorifera lacks flanges near the bulb,
but they indicated such a flange is present near the spermathecal bulb in L. grossi.
Little is known about the biology of lestoniids. They have only been found near the growing tips of
trees of the genus Callitris Ventenat (Cupressaceae) in mostly arid conditions, where they resemble small
scales or tortoise beetles (Gross 1975b, Cassis and Gross 2002).
2.2.7 Megarididae McAtee and Malloch, 1928
Members of the Megarididae are rare in collections, probably due to their small size (less than 5 mm),
and their secretive habits. It is also a small family in number of taxa, including a single extant genus
(i.e., Megaris) and currently 18 species (Table 2.2), all occurring in the Neotropics (McDonald 1979). A
second genus with one species (Minysporops dominicanus Poinar and Heiss) has been described from
Dominican amber (Poinar and Heiss 2013). This group was not recognized as a family-level taxon until
McAtee and Malloch (1928) proposed the subfamily Megaridinae within the Pentatomidae; they also
provided a key to species known at that time. Kormilev (1954) elevated it to family status, a position that
nearly all recent workers have recognized.
Members of this family, in general appearance, are quite similar to the Canopidae and some members
of the Plataspidae, only much smaller (Figure 2.16E). Diagnostic characters (Schuh and Slater 1995,
Schwertner and Grazia 2015) include the rounded shape, the convex dorsum, the flattened venter, and
the usual shiny black color, occasionally with reddish spots or markings. The anterolateral margins of
the head and pronotum are carinate; the bucculae are undeveloped. The antennae are four-segmented,
with many long setae that are about the same length as the diameter of the antennal segment in females,
and much longer in males. The scutellum is enlarged and nearly covers the abdominal dorsum (Figure
2.16E). Similar to the Canopidae, the forewings are longer than the abdomen, but they have a thin, weak
area at about the middle of the costa, thus allowing the wings to fold up underneath the scutellum. The
wing membrane lacks veins or has a single longitudinal vein. The tibiae lack spines or bristles; the tarsi
are two-segmented. The coxal combs are absent. The female spermathecal duct lacks a dilation and
sclerotized rod.
In the study by Grazia et al. (2008), the Megarididae are placed near the Plataspidae in their morpho-
logical studies. They did indicate that this placement was inconclusive because it was based heavily on
the similar shape and structure of the scutellum. They stated that “body shape alone is misleading with
regard to the establishment of phylogenetic affinities.” Unfortunately, they were not able to obtain fresh
material to do DNA studies, so the phylogenetic placement of this family within the Pentatomoidea
remains unclear.
The biology and ecology of the megaridids are poorly known. It is believed that all species are exclu-
sively phytophagous. Megaris puertoricensis Barber and M. semiamicta McAtee and Malloch have been
recorded feeding on flowers of Eugenia L. species (Myrtaceae) (Schuh and Slater 1995). More recently, a
specimen of an unknown species of Megaris was collected in a light trap placed inside a plot of cultivated
species of Eucalyptus L’Héritier de Brutelle (Myrtaceae) in the state of São Paulo, Brazil (Cristiano F.
Schwertner, unpublished data).