Cerodontha (Poemyza) inconspicua (Malloch)

Eiseman, Charles S. & Lonsdale, Owen, 2018, New state and host records for Agromyzidae (Diptera) in the United States, with the description of thirty new species, Zootaxa 4479 (1), pp. 1-156 : 45

Cerodontha (Poemyza) inconspicua (Malloch)

( Figs. 29 , 132 )

Material examined. MISSOURI: Franklin Co., Gray Summit , Shaw Nature Reserve , 1.vii.2015, em. 30.iv– 15.v.2016, C.S. Eiseman, ex Elymus virginicus , #CSE2434, CNC634783–634785 (2♂ 1♀) .

Hosts. Poaceae : Elymus * virginicus L. Malloch (1913) , Frick (1959) and Spencer (1969) recorded the host of the holotype as an unspecified Agropyron , but Spencer & Steyskal (1986) stated that it was A. repens , a synonym of Elymus repens (L.) Gould. If this is specified on the label, it is unclear why it was omitted by both Malloch and Frick. Boucher & Wheeler (2001) noted that other grasses likely serve as hosts.

Leaf mine. ( Fig. 132 ) The single photographed example began with two eggs inserted near the leaf margin. The larvae at first mined apically, forming gradually widening linear mines that eventually merged. They reversed direction several times, ultimately forming a whitish blotch that occupied the full width of the leaf. It was nearly full-depth, appearing partly pale green and partly whitish on the lower surface. The black frass was mostly in small grains, initially forming two rows but later more irregularly scattered.

Puparium. ( Fig. 29 ) Spencer & Steyskal (1986) state that the puparium is black, but it was brown to reddishbrown in all of our specimens. As illustrated by Frick (1959) and described by Spencer & Steyskal, the posterior spiracles are on widely separated projections. In the mine described above, the two puparia were already formed near the center of the mine at the time of collection. Other larvae, which were elongate and white with a faint bluegreen tinge, emerged a few days later and pupated externally. Adults were reared from both internal and external puparia.

Distribution. USA: CA, CO, *MO, NC, UT; Canada: AB, YT ( Boucher & Wheeler 2001). Spencer (1969) reported other specimens from AB, BC, MB, ON, and QC, but Spencer & Steyskal (1986) suggested that these, along with others from Finland and Poland, represent another undescribed species in the Cerodontha (Poemyza) atra complex (“superspecies”).

Comments. Our rearing suggests this species may be univoltine. The label for the holotype from Colorado, which is apparently the only previous reared specimen, includes just one date (28 July 1910), which might be either the collection date or the emergence date ( Malloch 1913).

Figures

FIGURE 22–29. Figure 22: Cerodontha (Butomomyza) angulata (Loew), empty puparium. Figure 23: Cerodontha (Butomomyza) sp. 1., empty puparia (left one parasitized by a braconid wasp). Figure 24: C. (Dizygomyza) edithae spec. nov., adult male. Figures 25–26: C. (D.) feldmani spec. nov.; 25: adult male; 26: empty puparium. Figure 27: C. (D.) morosa (Meigen), empty puparium. Figure 28: C. (Poemyza) incisa (Meigen), puparium. Figure 29: C. (P.) inconspicua (Malloch), puparia.

FIGURES 124–132. leaf mines; 124: Cerodontha (Butomomyza) angulata (Loew) in Dichanthelium clandestinum (puparium on leaf surface at lower left); 125: C. (B.) angulata in Carex sp.; 126: C. (C.) dorsalis (Loew) in Triticosecale sp.; 127: C. (Dizygomyza) edithae spec. nov. in Iris versicolor (puparium at left); 128: C. (D.) feldmani spec. nov. in Carex flaccosperma (puparium at far left; other dark spot is a dead larva); 129: C. (D.) cf. iraeos (Robineau-Desvoidy) in Iris cristata (brown puparium to right of black frass spot); 130: C. (D.) morosa (Meigen) in Carex leptonervia (puparium at right); 131: C. (Poemyza) incisa (Meigen) in Cinna arundinacea (transmitted light, with two puparia); 132: C. (P.) inconspicua (Malloch) in Elymus virginicus (transmitted light, with two puparia).