Hister incognitus Marseul, 1854, 289 [India].
Margarinotus incognitus: Wenzel, 1944: 126; Mazur, 1997: 94 [Taiwan]; Ohara, 1999: 15; Mazur & Zhou, 2001: 74 [China].
Rescription (Ohara, 1999: 15).
Body length, PPL, male, 5.3-7.5 mm, female, 6.4-8.4 mm, PEL, male, 4.9-6.4 mm, female, 5.8-7.1 mm. Width, male, 4.0-5.2 mm, female, 4.8-5.9 mm. Biometric data are given in Table 3. Body oblong-oval, black and shining.
Frontal stria of head (Fig. 7A) complete and well impressed, and interrupted and bent inwards at middle; disk sparsely and finely punctate, the punctures separated by two to four times their diameter.
Marginal pronotal stria (Fig. 7B) complete laterally and broadly interrupted behind head. Outer lateral stria usually present on apical half, and sometimes its basal end extends to basal two-thirds, but not extending beyond end of inner lateral stria. Inner lateral stria complete, straight on apical portion. Disk of pronotum evenly and finely punctate, the punctures sometimes becoming coarser between two lateral striae. Antescutellar area with a longitudinal punctures.
Epipleural fossette feebly excavate and densely covered with large punctures. Marginal elytral stria absent. Marginal epipleural stria complete and with large punctures. External subhumeral stria (Fig. 7B) deeply impressed and abbreviated at basal sixth. Internal subhumeral stria absent. Oblique humeral stria present on basal third. First to 3rd dorsal striae complete and feebly crenate, but the 3rd sometimes obsolete on apical half; basal end of the 2nd feebly bent outwards. Fourth dorsal stria on apical third rudimentary, often absent. Fifth stria represented by a few punctures apically. Sutural stria represented by a few punctures or a fragmental stria on apical fourth. Disk of elytra with subapical depression.
Pygidia (Fig. 8C) finely alutaceous. Propygidium densely covered with coarse punctures, which are separated by half to twice their diameter, with a few moderately sized punctures intermingled. Pygidium more densely punctate than propygidium, the punctures minute at apex.
Prosternal lobe (Fig. 7C, 8E) round at apex, its marginal stria narrowly interrupted at middle. Disk of lobe coarsely punctate, the punctures becoming finer medially. Prosternal keel without carinal stria.
Anterior margin of mesosternum (Fig. 8E) deeply emarginate at middle, its marginal stria complete and subcariniform, and another short stria present behind anterior angle. Disk of mesosternum sparsely covered with fine punctures, which are separated by about five times their diameter. Meso-metasternal suture obtusely angulate at middle. Lateral metasternal stria (Fig. 8F) well impressed and carinate, extending obliquely and posteriorly, and not united with the oblique stria that extends inwards form the middle of metasternal-metepisternal suture. Post-mesocoxal stria extending along the basal margin of mesocoxa and its outer end attaining to middle of metasternal-mesepimeral suture. Intercoxal disk of metasternum sparsely clothed with fine punctures, and feebly depressed along the longitudinal suture. Lateral disk of metasternum densely covered with large and shallow punctures, which become finer posteriorly, and with long hairs.
Intercoxal disk of 1st abdominal sternum with sparse fine punctures; coarse punctures along 1st abdominal stria. First abdominal stria complete and deeply impressed.
Protibia (Fig. 7D, E) with 6 to 8 denticles on outer lateral margin and 3 to 4 small denticles on apical margin. Ventral surface of profemur with posterior marginal stria on apical fourth.
Male genitalia as shown in Fig. 9. Ratio in length of paramera to basal piece of aedeagus 3.86.
Female genitalia as shown in Fig. 7F and G. Spermatheca consisting of 6 small sacs.
Specimens examined.
Type material. Type (Muséum Naturelle, Paris). 1 ex. Sex undetermined, pinned; labeled: 1. 85, Hister incognitus m. ; 2. Muséum Paris, Coll. De Marseul, 2842-90.; 3. Type; 4. 85, Hister incognitus m..
[Proper] Nantou Hsien: Suifeng, alt. 2,400 m (1 female, 2/iv/1986), M. Suwa. Chiai Hsien: Shihou, alt. 2,318 m, Alishan, (10 males and 7 females, 9/iv/1986), M. Ohara; Alishan, alt. 2,3002,500 m (1 male and 4 females, 8/iv/1986), M. Ohara; (1 male, 8/vii/1979), M. Suwa. Hualien Hsien: Tayulin, alt. 2,656 m (1 ex., 14/viii/1989), M. Ohara.
Distribution. Taiwan (Highlands).
Remarks. I have had an opportunity to examine the type specimen of incognitus from India. According to my careful comparison with the type the Taiwanese specimens differ in the following characters: the basal end of outer pronotal lateral stria does not extend to the end of inner one; the fourth dorsal elytral stria present on apical fourth; the marginal stria of the prosternal lobe not broadly interrupted at middle; the anterior margin of the prosternal lobe not strongly projected; the lateral disk of metasternum furnished with hairs; the punctures of the first abdominal sternum becoming coarser laterally. Dr. S. Mazur (personal communication), however, found several geographical forms of the species on the basis of Nepalese, Chinese, Indian and Taiwanese specimens, including the form noted here. As to the structure of the male genitalia, incognitus is also similar to M. striola succicola. The differences observed between the species and striola involve the shape of median armature of median lobe of the male genitalia and the coarse punctures of meso- and metasterna of striola. M. incognitus belongs to the weymarni-group (Ohara, 1989). This species occurs under carrion and human excrement.
Fig. 7. Margarinotus (Ptomister) incognitus (Marseul). A: Head, frontal view. B: Pronotum and left elytron. C: Ventral side of adult, ventral view. D: Left protibia, dorsal view. E: Ditto, ventral view. F: Female genitalia, spermatheca, vagina and bursa copulatrix, lateral view (left side). G: Spermatheca. [A-E: no. 9916, Suihou, Alishan; F, G: no. 9920, Alishan]. (Ohara, 1999).
Fig. 8. Margarinotus (Ptomister) incognitus (Marseul). A: Head and pronotum,
oblique view. B: Left elytron, oblique view. C: Propygidium and pygidium,
caudal view. D: Punctation of pygidium. E: Prosternum, ventral view. F:
Mesosternum, metasternum and epipleura of elytron, ventral view. [A-D: no.
9936, Liukuei; E-F: no. 9934, Shihou]. (Ohara, 1999).
Fig. 9. Margarinotus (Ptomister) incognitus (Marseul). Male genitalia.
A: Aedeagus, dorsal view. B: Ditto, lateral view. C: Ninth and 10th tergites,
dorsal view. D: Ditto, lateral view. E: Ninth sternum (spicule), dorsal
view. F: Eight tergite and sternum, dorsal view. G: Ditto, lateral view.
[no. 9916, Suihou, Alishan]. (Ohara, 1999).