Gestroiella Montandon, 1897: 371

Dan, Polhemus, John, Polhemus & Sites, Robert, 2008, A Revision Of The Indochinese Genera Cheirochela And Gestroiella Heteroptera Naucoridae And A Review Of The Tribe Cheirochelini, Raffles Bulletin of Zoology 56 (2), pp. 255-279 : 267

Gestroiella Montandon, 1897: 371 .

the shapes of the male parameres. In this regard, they present problems similar to the Neotropical genus Cryphocricos , of which Usinger (1947) wrote “...specimens exhibit relatively few characters which are useful to the taxonomist. The colouration is rather uniform, the male genitalia are quite similar throughout and such differences as are seen in the female genital plates are quite variable. As in some other Naucorid groups, each species has distinctive facies but the differences are illusive or difficult to describe, e. g. degree of convexity or curvature of pronotal or other margins.”

One internal character that seems to be consistently useful for species separation is the shape of the medial process of the male genital capsule ( Fig. 30 ), which projects posteriorly between the parameres. The tip of this process may be prolonged to varying degrees, and simple or bifurcate. The male parameres also show some degree of difference between species ( Fig. 26–28 ), although this is more a matter of degree, along the lines of the foregoing quote from Usinger. The distribution of posteromedial hair tufts on the female abdominal sternites, which initially seemed useful for species separation, has proven variable within individual species as more material has become available. The key below therefore relies on body size; the male medial process, and geographic distribution.

Figures

Figs. 26–30. Gestroiella species, male genitalia, structural details: 26, G. insignis, paramere; 27, G. limnocoroides, paramere; 28, G. siamensis, paramere; 29, G. limnocoroides, phallotheca; 30, G. siamensis, dorsomedial process of genital capsule.