Chorosoma schillingii

Rohanová, Markéta & Vilímová, Jitka, 2019, Nymphal development of Rhopalus maculatus and Chorosoma schillingii (Hemiptera: Heteroptera: Rhopalidae: Rhopalinae) and development of trichobothrial pattern in Rhopalidae, Zootaxa 4564 (2), pp. 367-390 : 384

Chorosoma schillingii

First instar ( Figs. 29 , 45, 47 , 63–66 ). Sternum 3: median long trichobothrium, middle short trichobothrium, and lateral precursor seta medially in wide V-shaped pattern. Sternum 4: median long trichobothrium, middle short trichobothrium and lateral long trichobothrium medially in transverse line. Sternum 5: median short trichobothrium, middle long trichobothrium, and lateral long trichobothrium laterally in transverse line. Sternum 6: median short trichobothrium, middle long trichobothrium, and lateral long trichobothrium laterally in transverse line. Sternum 7: only two trichobothria present, median short trichobothrium and lateral long trichobothrium laterally in transverse line.

Second instar to adult ( Figs. 30–33 , 67–71 ). Sternum 3: median long trichobothrium, middle long trichobothrium, and lateral short trichobothrium in wide V-shaped pattern. Sterna 4–7: trichobothrial pattern identical to that of 1 st instar.

Variation. Several differences from the general trichobothrial pattern described were recognized. Four trichobothria arranged asymmetrically in a transverse line on only one side of sternum 4 occurred in several Chorosoma schillingii adults. The following unusual arrangement was recognized in several specimens of the 3 rd – 5 th instars and the adults of both species — the trichobothria on one side of the sternum 5 or 6 are not in a straight line but the middle is distinctly more anterior or more posterior than the others. Also, in one specimen of the 1 st instar of C. schillingii , we found a precursor seta on one side of sternum 5 in the position of a median short trichobothrium.

Figures

FIGURES 29–33. Chorosoma schillingii, nymphal instars, (ventral view of abdomen, real chaetotaxy omitted except the right half of abdominal sterna VI–IX; right half of figure = natural left side of body with trichobothrial alveoles illustrated as open circle; left half of figure only with symbols illustrating trichobothrial pattern). (29) 1 st instar. (30) 2 nd instar. (31) 3 rd instar. (32) 4 th instar. (33) 5 th instar. Scale bars: 29–31 = 0.5 mm, 32, 33 = 1.0 mm. Lettering: III–VII, abdominal segments; Sp, spiraculum; solid circle and short seta, precursor seta; open circle and short seta, short trichobothrium; open circle and long seta, long trichobothrium.

FIGURES 45–47. Detailed view of base of long trichobothrium and precursor seta in alveoles, 1 st instar (SEM): (45, 47) Chorosoma schillingii. (46) Rhopalus maculatus. (45) base and alveole of long trichobothrium. (46, 47) alveole and precursor seta. Lettering: Ps, precursor seta; Tl, long trichobothrium.

FIGURES 63–71. Chorosoma schillingii, detail of abdominal trichobothria (ventral view; SEM, real situation, schemes on Figs 29-33). (63–66) 1 st instar. (67–71) 2 nd instar. (63, 64, 67–69) right side of abdominal venter. (65, 66, 70, 71) left side of abdominal venter. (63) sternum 3 and 4. (64, 69) sternum 5. (65, 70) sternum 6. (66, 71) sternum 7. (67) sternum 3. (68) sternum 4. Lettering: Ps, precursor seta; Tl, long trichobothrium; Ts, short trichobothrium.