Cuticular parts of the spermatheca and associated vaginal structures (chiefly the ring sclerites of the parietovaginal glands) have been examined and compared in 190 cydnid species representing 65 genera and all five subfamilies currently recognized in the family (Amnestinae, Cephalocteinae, Cydninae, Garsauriinae, Sehirinae). Four species belonging to genera formerly included within the Cydnidae (Dismegistus, Parastrachia, Thaumastella, Thyreocoris) were also examined. Morphology of the three main parts of the spermatheca [seminal receptacle (distal bulb), intermediate part (pump apparatus), spermathecal duct] is described. Four main types of spermathecae can be recognized from the distal receptacle and the intermediate part: the amaurocorine type (in Sehirinae: Amaurocorini), amnestine type (in Amnestinae), garsauriine type (in Garsauriinae), and "cydnoid" type (in Cephalocteinae + Cydninae: Cydnini, Geotomini + Sehirinae: Sehirini). No synapomorphy of these types was found which suggests that the currently conceived Cydnidae are not monophyletic. Moreover, out of these four types only the "cydnoid" is typically pentatomoidean due to the presence of an intermediate part usually well delimited by two flanges and having always an unsclerotized flexible zone as well as two internal cuticular structures (septum and fretum) partly obstructing the lumen. The simple tubular amaurocorine type is unusual and aberrant within all Pentatomoidea. The amnestine and garsauriine types display some similarities with taxa outside the Pentatomoidea, especially with some lygaeoid or coreoid spermathecae, mainly in the structure of the intermediate part not delimited proximally (absence of flanges) and devoid of the flexible zone. Within the "cydnoid" type, six spermathecal facies can be characterized principally according to the shape of both the apical reservoir along with the intermediate part, and the differentiations of the spermathecal duct. It has been impossible to find any synapomorphy for all species and for the six facies belonging to the "cydnoid" type of spermatheca. We suggest that the Cydnidae as defined presently are probably a polyphyletic group; moreover its main "cydnoid" branch, called by us Cydnidae sensu stricto (Cephalocteinae + Cydninae + Sehirinae: Sehirini) seems to be relatively recent among the Pentatomoidea. Nishadana and Nishocoris are transferred from Garsauriinae back to Cydninae: Cydnini and the tribe Amaurocorini (Sehirinae) is upgraded to a separate subfamily Amaurocorinae stat. nov. Moreover, we regard the Geotomini and the Sehirini both as non-monophyletic and we indicate that by appending them sensu lato (Geotomini "s. l.", Sehirini "s. l.")

Parastrachiidae is a small stinkbug family containing only one genus and two species, Parastrachia japonensis (Scott) (Hemiptera: Heteroptera: Pentatomoidea) and Parastrachia nagaensis Distant. The geographic distribution of the genus has been poorly studied. Niche conservatism refers to that idea that closely related species are more ecologically similar than would be expected, whereas niche divergence predicts they occupy distinct niche spaces. The existence of only two species within one genus suggests niche conservatism or differentiation might exist among them. Herein, the distribution of the genus was mapped, potential distributions were predicted using ecological niche modeling, and climate spaces occupied by the two species were identified and compared. Our outlined map supports the general spreading route proposed by Schaefer et al. The potential distributions suggest that the genus’ range could extend beyond its presently known distribution, and further investigation into this area could aid in their conservation, particularly P. nagaensis. The niche space inferred by ecological niche modeling suggests the two species do not occupy identical habitat, but the differences between their models could simply be due to the differential availability of habitat in the different regions that they occupy.

The “cydnoid” complex of pentatomoid families, including Cydnidae, Parastrachiidae, Thaumastellidae, and Thyreocoridae, is morphologically defined by the presence of an array of more or less flattened stout setae (called coxal combs), situated on the distal margin of coxae. These structures, suggested to prevent the coxal-trochanteral articulation from injuries caused by particles of soil, sand or dust, by their nature and function are unknown elsewhere in the Heteroptera. As such, coxal combs were regarded as a synapomorphy of this group of families, and enabled the definition of it as a monophylum. In this study, the monophyly of the “cydnoid” complex of families is tested for the first time, based on the combined analysis of nuclear ribosomal DNA sequences (28S rDNA D3 region, and 18S rDNA). Combined analyses of both genes are performed using Bayesian methods with the covarion option in MrBayes 3.2.0. Non-monophyly of the entire “cydnoid” complex of families, and independent origins of their coxal combs is suggested. The family Thaumastellidae is demonstrated not to be part of this complex as previously proposed. Challenging the existing classification system, the use of the name “cydnoid” complex is indicated as unwarranted, and therefore it should no longer be applied to this group of families.

Insects can cause a variety of dermatologic problems usually presenting with inflammatory skin lesions. Cydnidae insects (family, Cydnidae; order, Hemiptera; su

Coxal combs are described for 26 species of 21 genera, representing all currently recognized subfamilies and their tribes within the Cydnidae sensu lato (i.e., Amnestinae; Amaurocorinae; Garsauriinae; Cephalocteinae: Cephalocteini and Scaptocorini; Cydninae: Cydnini and Geotomini s. lato; Sehirinae: Sehirini s. lato). In addition, Thyreocoris scarabaeoides Linnaeus, 1758, and Strombosoma impictum Amyot et Serville, 1843 (Thyreocoridae); Thaumastella aradoides Horváth, 1896 (Thaumastellidae); and Parastrachia japonensis (Scott, 1880), P. nagaensis Distant, 1908, Dismegistus binotatus (Westwood, 1837), and D. fimbriatus (Thunberg, 1783) (currently placed within Parastrachiidae), have also been studied. 22 species were investigated using SEM techniques for the first time. Three basic types of setae, making up the coxal comb, were recognized during the study, i.e., stout setae, gutter-like setae, and scale-like setae. Two main types of the coxal combs are described, i.e., (1) the coxal comb composed of an irregular row of long, apically sharpened, stout setae (Cydnidae: Cephalocteinae: Scaptocorini; and Parastrachiidae), and (2) the coxal comb composed of a regularly aligned row of gutter-like or scale-like setae (all other subfamilies and tribes of the Cydnidae s. lato, Thaumastellidae, and Thyreocoridae). Functional, taxonomic, and phylogenetic significance of the coxal combs is also briefly discussed.