Metrichia mastelleri Harris and Flint, 2016

Harris, Steven C. & Oliver S. Flint, Jr., 2016, New species of microcaddisflies (Trichoptera: Hydroptilidae) from the western United States, Canada, Mexico and Belize, Insecta Mundi 2016 (499), pp. 1-22 : 6-7

Metrichia mastelleri Harris and Flint , new species

Fig. 11 - 13

This species is placed in the genus Metrichia on the basis of its having abdominal pouches and characters typical of the genus, unmodified head and antennae, 5 segmented maxillary palps, with the first two segments small, simple tenth tergum, button-like cerci, and a phallus having large hooks, but lacking complex medial structures. The new species differs from other members of the genus in the presence of very short inferior appendages, although some species of Metrichia , such as M. yalla (Flint) and M. sencilla Harris and Armitage , also have relatively short inferior appendages, and in the bifid dorsolateral processes. The posterior pair of internal glands each has a large sclerotized spike, which is also seen in M. rawlinsi (Flint and Sykora) . Based on the presence of internal glands between abdominal segments V and VI and the pair of medial phallic hooks, M. mastelleri should tentatively be placed in the nigritta group of Flint (1972).

Male. Length 3.2 mm. Head without modification, 3 ocelli; antennae simple with 18 segments. Body brown in alcohol, mesoscutellum with medial furrow, metascutellum triangular; wings appearing to have lightly sclerotized, setose bands, veins few and reduced; legs with spinal formula of 1,3, 4, spine on foreleg small and apex of fore femur produced into small lobe. Abdominal segment V with pair of internal sacs posterodorsally, cluster of stout setae ventrally. Segment VI with small, inconspicuous internal sacs posterodorsally, each bearing a thick, sclerotized spine and band of stout setae. Segments VII annular, short ventromesal process on posterior margin. Segment VIII in lateral view wide dorsally, narrowing ventrally; dorsally annular, ventrally deeply incised. Segment IX in lateral view tapering posterodorsally and fused with tergum X, tapering posteroventrally to acute apex, tapering anteroventrally to rounded apex; in dorsal view ovate, slightly incised on posterior margin; dorsally fused with tergum X. Preanal appendages (cerci) in lateral view ovate, narrow basally, widening distally; in dorsal view button-like and setose. Dorsolateral process elongate and narrow, slightly curving ventrad to narrow apex; in ventral view bifid with narrow arms, left arm with thin ventral lobe apically. Segment X elongate and rectangular in lateral view, membranous distally; in dorsal view wide basally, narrowing to emarginated apex. Inferior appendages in lateral view very short, narrow basally, widening distally to truncate apex; in ventral view widening posteriorly to truncate apex, curved on outer margins. Phallus tubular in dorsal view, wide basally, narrowing mesally and distally, pair of sclerotized hooks mesally, elongate tube encasing the ejaculatory duct apically; in lateral view wide basally and in mid-section bearing pair of sclerotized hooks, narrowing distally, apex an elongate thin tube.

Type material. Holotype, male - United States, Arizona, Yavapai County, Fossil Creek , 7.5 km (air) NW Strawberry, N34 o 25.4’, W111 o 34.4’, 13 May 2002, O. Flint, Jr. and E. Masteller ( NMNH).

Etymology. We take great pleasure in naming this species for our colleague Edwin C. Masteller, who along with the junior author collected this species, in recognition of his many contributions to the study of caddisflies in North America.

Notes. As the genus Metrichia is rare in North America, with only two species known M. nigritta (Banks) and M. arizonensis (Flint) ( Rasmussen and Morse 2014) , both of which occur in the southwest, we have provided drawings of the body of the adult male as well as the genitalia.

New records and range extensions

Neotrichia mobilensis Harris , which was previously known from only Alabama and Texas ( Rasmussen and Morse 2014), was collected in Mexico as follows: Veracruz, Tamuin, 13 April 1975, J. Bueno, 2 males (NMNH).

Mayatrichia tuscaloosa Harris and Sykora , previously known from a single specimen collected in Alabama, was collected in Texas and Mexico as follows: Texas, Travis County, Bull Creek at Saint Edwards Park, N30.405826, W97.793553, 9 July 2014, L. Pulliam 1 male (UNT) and Mexico, Neuvo Leon, 18 mi W Linares, 12 September 1976, blacklight, J. Powell and J. Chemsak, 2 males (UCB). As this species was originally described from a single specimen, we have provided new illustrations ( Fig. 14 ).

Figures

Figure 11. Metrichia mastelleri, n. sp. Adult male. A. Head and thorax, dorsal view; B. Maxillary palp, ventral view; C. Abdominal segments V and VI, dorsal view.

Figure 14. Mayatrichia tuscaloosa Harris and Sykora. Male genitalia. A. Lateral view; B. Ventral view; C. Dorsal view; D. Phallus, lateral.