Macrostemum digramma (McLachlan 1871), 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

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Macrostemum digramma (McLachlan 1871)


Macrostemum digramma (McLachlan 1871)  

Figs. 8 View FIGURE 8 A –E

Macronema digramma McLachlan 1871: 131   [type locality: Brazil, Minas Gerais; BMNH; ♂]; Ulmer 1907 a: 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 View FIGURE 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 View FIGURE 8 B); in dorsal view, with posterior margin bearing small medial truncate keel and long setae bordering right and left margins ( Fig. 8 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 8 B). Phallus arched; in lateral view, apex slightly angled ( Fig. 8 View FIGURE 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 View FIGURE 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, 23 º 20 ’ 46.01 ’’S, 44 º 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 1 ª ordem, 22 º 25 ’00.5’’S, 42 º 36 ’ 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, 22 º 26 ’ 41.3 ’’S, 42 º 56 ’ 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, 22 º 26 ’ 41.3 ’’S, 42 º 56 ’ 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).