Macrostemum digramma (McLachlan 1871)

França, Diogo, Paprocki, Henrique & Calor, Adolfo R., 2013, The genus Macrostemum Kolenati 1859 (Trichoptera: Hydropsychidae) in the Neotropical Region: Description of two new species, taxonomic notes, distributional records and key to males, Zootaxa 3716 (3), pp. 301-335 : 316

Macrostemum digramma (McLachlan 1871)

Figs. 8 A–E

Macronema digramma McLachlan 1871: 131 [type locality: Brazil, Minas Gerais; BMNH; ♂]; Ulmer 1907a: 80 [wings; ♂]. Macrostemum digramma (McLachlan 1871) ; Flint et al. 1999: 68 [taxonomic notes; distribution]; Paprocki et al. 2004: 8 [distribution]; Dumas et al. 2009: 358 [distribution]; Calor 2011: 321 [distribution].

The male genitalia of this species are similar to those of Macrostemum brasiliense but may be diagnosed by the anterior margin of abdominal segment IX, which is nearly straight in lateral view, and the phallotremal sclerite with its anterior margin only slightly concave in ventral view. Furthermore, the forewings of M. digramma are predominantly black with only two narrow, longitudinal, hyaline spots on the medial area.

Synopsis. Adults in alcohol. Forewing mean length 12.7 mm (10.53–13.87 mm, n=17). Head brown, with or without yellow spot behind eyes. Compound eyes brown. Scapes brown, with ferruginous setae. Maxillary palps yellow, with ferruginous and yellow setae. Prothorax brown, with or without yellow spot on pleural region. Meso- and metathorax brown or yellowish-brown. Legs brownish-yellow. Tibial spur formula 2,4,4. Forewings mostly dark, each with only two longitudinal hyaline narrow spots on medial area; discoidal cell present; radial sector normal ( Fig. 8 A).

Male genitalia. Abdominal segment IX, in lateral view, with anterior margins nearly straight; posterior margins sinuous, deeply notched above middle, bordered by long setae above and below notch ( Fig. 8 B); in dorsal view, with posterior margin bearing small medial truncate keel and long setae bordering right and left margins ( Fig. 8 E). Segment X, in dorsal view, bilobed, each lobe apically rounded and with subapical wart; pair of subdorsal longitudinal rows of small setae from midlength to each wart ( Fig. 8 E); in lateral view, triangular with blunt apex, with irregular row of small ventrolateral setae in apical half in addition to subdorsal row of short setae and warts ( Fig. 8 B). Inferior appendages uniformly wide and covered uniformly by small setae; each with basal segment approximately 2.5 times length of apical segment; apical segment strongly upcurved ( Fig. 8 B). Phallus arched; in lateral view, apex slightly angled ( Fig. 8 C); in ventral view, phallotremal sclerite bearing pair of spine-like anterodorsal processes, anterior margin slightly concave, posterior margin bearing pair of rounded prominences ( Fig. 8 D); phallotrema rounded, concave, apically positioned on posterodorsal surface of phallus.

Material examined. BRAZIL: São Paulo: E.B. Paranapiacaba, 4.xi.1963, 1 male (alcohol; MZSP); Ubatuba, pé da Serra do Mar, Rio da Fazenda, 23º 20’ 46.01’’S, 44º 50’ 59.61’’W, 52 m, 19.iv.2004, J.L. Nessimian & A.A. Huamantico leg., 1 male (alcohol, DZRJ 1734); Rio de Janeiro: Cachoeiras de Macacu, Parque Estadual Três Picos, Mata do Jequitibá, riacho de 1ª ordem, 22º25’00.5’’S, 42º36’28.2’’W, 328 m, 7.v.2006, A.P.M. Santos, L.L. Dumas, J.L. Nessimian leg., 1 male (alcohol; DZRJ 3428); Rio de Janeiro, Parque Nacional da Tijuca, trilha ACM, 10.x.1992, L.F.M. Dorvillé leg., 2 males (alcohol; DZRJ 1213); Teresópolis, Rio Paquequer, represa, 22º26’41.3’’S, 42º56’31.9’’W, 13.x.1996, J.L. Nessimian leg., 5 males (alcohol; DZRJ 1371); same data except, A.A. Huamantico leg., 5 males (alcohol; DZRJ 1393); same data except, 23.xi.1991, J.L. Nessimian leg., 7 males (alcohol; DZRJ 1395); same data except, 15.ii.1991, L.F.M. Dorvillé, E.R. Silva, J.L. Nessimian leg., 1 male (alcohol, DZRJ 1396); same data except, 11.iv.1992, E.R. Callil leg., 1 male (alcohol, DZRJ 1397); same data except, Venda Nova, 23.ix.1991, E.R. Silva & J.L. Nessimian leg., 1 male (alcohol; DZRJ 1390); same data except, Vale da Revolta, 22º26’41.3’’S, 42º56’31.9’’W, 29.xii.1991, E.R. da Silva leg., 1 male (alcohol; DZRJ 1391); same data except, 19.x.1991, M.E. Felix leg., 2 males (alcohol; DZRJ 1392).

Distribution. Brazil (MG, RJ, SP).

Figures

FIGURE 8. Macrostemum digramma (McLachlan 1871). A, right fore- and hind wings, dorsal view; B – E, male genitalia: B, left lateral view; C, phallus, left lateral view; D, apex of phallus, ventral view; E, terga IX and X, dorsal view.