Higher Systematics of the Pentatomoidea 41
Burrower bug nymphs live within or near the surface of the soil, feeding on the roots or fallen seeds
of their hosts. They are typically oligophagous or polyphagous, feeding on the plants near the site where
they hatched from the eggs. As with most terrestrial Heteroptera, cydnids go through five nymphal
instars. The majority of cydnid species seems to be polyphagous with several plant families reported
as hosts (Timonin 1958, Becker 1967a, Mayorga and Cervantes 2001, Riis et al. 2005a,b, Chapin et al.
2006, Schwertner and Nardi 2015). On occasion, the bugs are reported as agricultural pests (Gallo et al.
2002, Riis et al. 2005a,b, Schwertner and Nardi 2015).
Some species, and some individuals within other species, are brachypterous and, thus, are unable to
fly. Those that can fly seem to take wing mostly for dispersal, but flying could also be for colonization
of new areas, location of food, and finding new mates (Willis and Roth 1962, Oliveira and Malaguido
2004, Nardi et al. 2008). Little is known about cydnid reproductive behavior. Soil-dwelling species mate
in the soil (Willis and Roth 1962, Nardi 2005). Similar to other Heteroptera, it appears that copulation
in the Cydnidae is mediated by chemicals and sound communication (Gogala et al. 1974, Gogala 1984,
Čokl et al. 2006, Pluot-Sigwalt 2008).
As expected from a group whose members live primarily on or near the ground, there are several
fossil genera and species known. Also, at least three family-level names have been proposed within
the Cydnidae. For example, Pinto and Ornellas (1974) erected two fossil families, the Pricecoridae
for Pricecoris beckerae Pinto and Ornellas and the Latiscutellidae for Latiscutella santosi Pinto
and Ornellas. Additionally, Popov (1986) proposed the subfamily Clavicorinae for two fossil gen-
era, Clavicoris Popov and Cretacoris Popov. Later, Popov and Pinto (2000) placed all three of these
family-groups as junior synonyms of the Amnestinae. Within the subfamily Amnestinae, there are
six genera and nine fossil species (Pinto and Ornellas 1974, Popov 1986, Thomas 1988, 1994a, Yao
et al. 2007); within the subfamily Cydninae, there are three genera and 41 fossil species (Heer 1853;
Oustalet 1874; Novák 1877; Scudder 1878, 1890; Förster 1891; Cockerell 1909; Henriksen 1922; Piton
1933; Théobald 1937; Statz and Wagner 1950; Jordan 1967; Kinzelbach 1970; Popov 1986, 2007;
Schaefer and Crepet 1986; Thomas 1994a); and within the Sehirinae, there are five fossil species (Statz
and Wagner 1950, Vršanský et al. 2015). There are currently six genera and 25 fossil species that have
not been placed to subfamily. Another fossil genus and species, Ovalocoris parvis Jordan, was origi-
nally described in the Lygaeidae but later (Popov 2007) transferred to the Cydnidae. Additionally,
there are three fossil species that were originally placed in the Cydnidae that have now been placed
elsewhere. That is, Cydnopsis affinis Jordan and C. ventralis Jordan have both been transferred to the
nepomorphan family Aphelocheiridae (Popov 2007), and the third species, Cydnopsis nigromembra-
nacea Jordan (1967) has been transferred to the Coleoptera (Popov 2007).
2.2.4.1 Key to the Subfamilies of Cydnidae (modified from Schuh and Slater 1995)
1 Clavi reaching beyond and meeting in a straight line beyond apex of scutellum, forming cla-
val commissure (Figure 2.3C); New World (except one species introduced into Old World)
(Figure 2.15F) .....................................................................................................Amnestinae
1’ Claval commissure absent ..................................................................................................... 2
2(1) Fore tibiae falcate or cultrate, much produced beyond tarsal insertion, therefore tarsi
appearing to arise at middle of tibial length (except in Cephalocteus where tarsus is inserted
apically or subapically) (Figures 2.3D, E); posterior tibiae strongly broadened; worldwide
(Figures 2.15G, H) ........................................................................................Cephalocteinae
2’ Fore tibiae not cultrate, tarsi arising at or near apices of tibiae (Figures 2.1E, G) .............. 3
3(2) A submarginal row of setigerous punctures present along each lateral pronotal margin
(Figure 2.3F); diameter of tarsal segment II subequal to diameters of tarsal segments I and
III (Figure 2.1E); worldwide (Figures 2.15J, K; 2.25B) .......................................Cydninae
3’ Pronotum lacking submarginal row of setigerous punctures along lateral margins; diameter
of tarsal segment II distinctly narrower than diameters of tarsal segments I and III (Figures
2.1G, H) ................................................................................................................................. 4