Pyrgus orcus (Stoll, 1780)

Carneiro, Mielke, Olaf H. H. & M, Mirna, 2013, Thorax and abdomen morphology of some Neotropical Hesperiidae (Lepidoptera), Insecta Mundi 2013 (327), pp. 1-47 : 12-14

Pyrgus orcus (Stoll, 1780)

Cervix and Prothorax. Cervix as in Urbanus teleus ( Fig. 3 ). The prothorax similar to that of Urbanus teleus , being different only in its smaller size (which is proportional to the entire size of the individual), and by the crease on the first third of the posterior extension of the dorsal plate of the pronotum, which is not as evident and does not present distinct sclerotization ( Fig. 7). The anterior portions of the parapatagia are more defined from the adjacent membrane and slightly narrower, proportionally ( Fig. 3 ). The posterior part of the spine I is distinctly wider forming a triangular plate with the anterior apex curved towards the inside of the body, as in the other species.

Mesothorax. Among all the species observed, Pyrgus orcus has shown to be the slimmest, presenting a certain lateral flattening in males ( Fig. 15 ). In females, this characteristic is less evident. The prescutum II is reduced in its width. The scutum II and the scutellum II are more melanized, which makes it difficult to visualize some of the structures. The median-lateral sulcus of the scutum II is less prominent, or sometimes inconspicuous.

The notal processes II are similar to those in Urbanus teleus , with the exception of the first one, which despite its proportional size and shape, is laterally directed, in contraposition to the body cavity ( Fig. 19 ). The subtegula is relatively smaller in length, and as in Urbanus teleus , reaches its posterior margin on the anterior margin of the basalare II. The subalare II does not present a thin posterior projection.

The tegulae, which are relatively larger, present a more prominent dorsal-anterior margin than in the previous species, and are located along the sides of the subtegular sclerites, which are slightly reduced ( Fig. 23 ).

The anepisternum II is delimited by an anepisternal suture II, with the same size, as in Pyrrhopyge charybdis ( Fig. 52 ). Ventrally, the katepisternum II is partially blended to the basisternum II, as observed in Urbanus teleus , as its coxal suture is similar to it and the marginopleural suture II is equally incomplete. Posteriorly to the basisternum II, there are the ventral articulations of the coxa II, which are also located after the discrimen II ( Fig. 11 ).

The epimeron II is not different in shape from the previously mentioned species. However, present a distinct suture in the anterior portion towards the integumental crease, which could represent a probable differentiation from a preepimeron, thus being denominated preepimeral suture II ( Fig. 19 ).

Metathorax. Similar to Urbanus teleus , it possesses the same differences in the internal crest, the marginopleural suture III and the paraepisternum III. The spot on the epimeron III was not visualized in any of the specimens observed ( Fig. 27 ). Males present a pair of cuneiform glandular pouches carved in the internal margin, which originate in a narrow membranous band between the epimeron III and the meron III. They are glandular structures associated to a brush of odoriferous bristles located on the tibiae ( Barth 1960). Laterally, it is possible to observe that the meron III is reduced in width by the development of the eucoxa III. The basicostal suture is equally developed, as in the previous species.

Legs. The legs are smaller, due to the reduced size of the individuals of this species ( Fig. 31 ). The femur I presents a smaller relative length, around 1.5 times the length of the tibia I. The coxa II presents a basicostal suture II not contiguous to the pleural suture II, intermingled with the pre-coxal suture II by a distance twice greater than the one observed in Urbanus teleus ( Fig. 7). In the posterior pair, the basicostal suture II is reduced, observed only through a slightly curved sulcus, posteriorly dislocated and discontinuous from the pleural suture III. The triangular sclerite is observed, in this case, as it is in Urbanus teleus , present in the meron II and absent in the meron III. The arolium is trifurcated, with two sharp dorsal projections and the ventral truncated as those found in the other species ( Fig. 60 ). The tarsal claw presents a ventral projection in the shape of a spine.

Wings. Both males and females present similar variation in wingspan length, with approximately 25 mm. The forewings are widened and triangular, with the discal cell a little longer than half the costal margin ( Fig. 35 ). Between the C and the Sc, there is a group of differentiated bristles, located on a tegumental crease, denominated costal folds ( Barth 1960), a secondary sexual character of males in certain Hesperiidae (Pyrginae) .

The dcs vein is difficult to visualize because of its transparency, which is similar to dcm and dci, and there is no significant sexual differentiation in the distance of the insertion of M 1 with R 4 +R 5. The discal cell is 1/5 smaller in length than the anal margin, or around half the length of the costal margin.

The 3A vein is twice the length in males than in females, and both do not extend past half the length of the CuA until its first bifurcation. In this species, it is possible to observe a small continuous projection of the 3A toward the external margin.

The hind wings present distinctly elongated scales on the costal margin ( Fig. 47 ). The M 2 vein is thin, occurring from the middle of M 1 and M 3, inserted in the junction between dcs and dci. There is sexual dimorphism in the m-cu and in the humeral vein, as in Urbanus teleus .

Abdomen. It is fusiform and laterally flattened (females present a smaller degree of flattening) ( Fig. 70 and 71 ). The tergal lobe is weakly sclerotized, similar to a lobe detached from the membrane and located on the first spiracle. All the bars that circle the spiracular opening of the first abdominal segment are similar to those in Urbanus teleus . The first tergum is distinctly developed, located above the tergopleural bar. The sterna are strongly reduced to small ventral plates, and devoid of the lateral-dorsal extensions which are well developed in Pyrrhopyge charybdis charybdis , or reduced in Urbanus teleus . There are no ventral prominences in the sterna in Pyrgus orcus .

The last pregenital segments do not present a membranous recess in both sexes ( Fig. 82 to 85). The eighth tergum in males is reduced to a triangular plate with bristles concentrating on its small apical angle. The sternum is reduced laterally and anterior-posteriorly, forming a small ventral square plate, with little sclerotization. In females, the tergum has an inverted trapezoidal shape, while the sternum is anterior-posteriorly elongated.

Male Genitalia. The tegument longer, covering over half the extension of the valva, and presenting slightly sclerotized lateral-ventral projections that connect median-ventrally to the gnathos ( Fig. 94 ). The uncus is cordiform, full of dorsal bristles, parted in the middle by a membranous fenestra visible in dorsal view ( Fig. 100 ). Ventrally, there is only one median line separating the two symmetrical structures located posteriorly to the triangular membranous orifice, which is contiguous to the rectangular opening observed between the tegument and the gnathos. The gnathos is spatula-shaped, highly sclerotized, full of setae on its surface, and is inserted on the ventral surface of the anal duct. Under the gnathos rest a triangular structure, also connected to the tergum by two thin dorsal projections which are inserted next to the ventral projections of the tegument. This sclerite is denominated fultura superior and was not found in other species studied. The fultura inferior has the same V-shape format of that in Urbanus teleus , although shorter and with an oblique inferior edge ( Fig. 104 ).

The saccus is slim, anteriorly extended, reaching 1/3 of the length of the ninth segment and does not present dorsal-anterior projections. Dorsal projections of the saccus and ventral projections of the tegument are similarly blended, forming a single annular piece. The valva is similarly developed, presenting a strongly sclerotized but reduced harpe, full of bristles on its anterior margin ( Fig. 95 ). The ampulla, as described to Palearctic species of Pygrus ( De Jong 1972), is not present. The sacculus is less prominent, though it presents long thorns on its posterior end. The costa is manifested as a tegumental crease of the dorsal margin of the valva, covered by bristles over all its extension, without membranous spots on its surface.

The aedoeagus follows the same shape pattern presented in Urbanus teleus , only slightly thicker ( Fig. 108 ). Anteriorly, the aedoeagus’ coecum is thin and does not present a considerable arch. The ejaculatory bulb is oval, without tubular shape next to the aedoeagus opening. In the posterior end, a group of small spines is ventrally observed on the right side, next to the orifice of the vesica, opposite to a single well developed and strongly sclerotized spine. Ventrally, there is another small spine on the left side, which is almost inconspicuous.

Female Genitalia. The sterigma forms a single semi-cylindrical plate ( Fig. 112 ). In ventral view, its trapezoidal aspect can be observed, where it has at its center an area with little sclerotization next to a glandular organ which is adhered to its anterior margin, whose function is yet unknown. It is directly coupled to the eighth tergum, which is well developed, semi-cylindrical and posteriorly shelters the anal papilla. The ostium bursa appears median-ventrally sheltered in a ventral concavity of the postvaginal lamella.

The bursa presents a terminal dilatation, anteriorly to the vertex found in the middle of its length ( Fig. 116 ). The spermatophore is composed of a globular terminal dilatation (sheltered by the dilatation in the body of the bursa), next to a thin and cylindrical anterior projection. The spermatophore is distinctly less sclerotized than that of the previous species. Anal papillae, which are slightly reduced in volume, present the same appearance as the previous species, provided with thin posterior apophyses that are distinctly longer than the ones found in Urbanus teleus .

Figures

Figures 1-4. Lateral view of cervical sclerite and prothorax. 1) Pyrrhopyge charybdis charybdis; 2) Urbanus teleus; 3) Pyrgus orcus; 4) Synapte silius.

Figures 13-16. Dorsal view of mesothorax and metathorax. 13) Pyrrhopyge charybdis charybdis; 14) Urbanus teleus; 15) Pyrgus orcus; 16) Synapte silius.

Figures 17-20. Lateral view of mesothorax. 17) Pyrrhopyge charybdis charybdis; 18) Urbanus teleus; 19) Pyrgus orcus; 20) Synapte silius.

Figures 21-24. Lateral view of internal surface of tegula. 21) Pyrrhopyge charybdis charybdis; 22) Urbanus teleus; 23) Pyrgus orcus; 24) Synapte silius.

Figures 50- 57. Lateral view of anepisternum II (Fig. 50 to 53) and coxopleural articulation II (Fig. 54 to 57). 50, 54) Pyrrhopyge charybdis charybdis; 51, 55) Urbanus teleus; 52, 56) Pyrgus orcus; 53, 57) Synapte silius.

Figures 9-12. Ventral view of cervix and thorax. 9) Pyrrhopyge charybdis charybdis; 10) Urbanus teleus; 11) Pyrgus orcus; 12) Synapte silius.

Figures 25-28. Lateral view of metathorax. 25) Pyrrhopyge charybdis charybdis; 26) Urbanus teleus; 27) Pyrgus orcus; 28) Synapte silius.

Figures 29-32: Internal surface of prothoracic, mesothoracic and metathoracic legs (left to right). 29) Pyrrhopyge charybdis charybdis; 30) Urbanus teleus*; 31) Pyrgus orcus; 32) Synapte silius*. *External surface illustrated.

Figures 58- 65. Lateral view of last tarsomere and pretarsum I (Fig. 58 to 61), and trochantin I (Fig. 62 to 65). 58, 62) Pyrrhopyge charybdis charybdis; 59, 63) Urbanus teleus; 60, 64) Pyrgus orcus; 61, 65) Synapte silius. a: trochantin I.

Figures 33-36. Dorsal view of clarified mesothoracic and metathoracic wings of males (left) and females (right). 33) Pyrrhopyge charybdis charybdis; 34) Urbanus teleus; 35) Pyrgus orcus; 36) Synapte silius.

Figures 42- 49. Details of wing-coupling mechanism viewed on ventral mesothoracic wingbase (left) and dorsal metathoracic wingbase (right). 42, 43) Pyrrhopyge charybdis charybdis; 44, 45) Urbanus teleus; 46, 47) Pyrgus orcus; 48, 49) Synapte silius.

Figures 70-73. Lateral view of male (Fig. 70, 72) and female (Fig. 71, 73) abdomens. 70, 71) Pyrgus orcus; 72, 73) Synapte silius.

Figures 74-89. Dorsal view from last tergum (two left columns) and ventral view from sternum (two right columns): 74 to 77) Pyrrhopyge charybdis charybdis; 78 to 81) Urbanus teleus; 82 to 85) Pyrgus orcus; 86 to 89) Synapte silius.

Figures 90-97. Lateral view of external surface of male genitalia (left), and internal surface of valvae (right). 90, 91) Pyrrhopyge charybdis charybdis; 92, 93) Urbanus teleus; 94, 95) Pyrgus orcus; 96, 97) Synapte silius.

Figures 98-105. Dorsal (left) and ventral (right) view of ninth and tenth tergum of male genitalia. 98) Pyrrhopyge charybdis charybdis; 99) Urbanus teleus; 100) Pyrgus orcus; 101) Synapte silius. 102-105. Posterior view of fultura inferior. 102) Pyrrhopyge charybdis charybdis; 103) Urbanus teleus; 104) Pyrgus orcus; 105) Synapte silius.

Figures 106-109. Different views of the penis: left lateral, right lateral, ventral and dorsal views (top to bottom). 106) Pyrrhopyge charybdis charybdis; 107) Urbanus teleus; 108) Pyrgus orcus; 109) Synapte silius.

Figures 110-113. Lateral view of eighth, ninth and tenth segments which form the female genitalia 110) Pyrrhopyge charybdis charybdis; 111) Urbanus teleus; 112) Pyrgus orcus; 113) Synapte silius.

Figures 114-117. Ventral view of female genitalia. 114) Pyrrhopyge charybdis charybdis; 115) Urbanus teleus; 116) Pyrgus orcus; 117) Synapte silius.