Monoxia elegans Blake

(Figs. 107–108, 166)

Collected specimens. COLORADO: Chaffee Co., Big Bend State Wildlife Area, 8.vii.2015, C.S. Eiseman, on Atriplex canescens, # CSE1686 (5 adults, MLBM) .

Hosts. * Amaranthaceae: Atriplex canescens (Pursh) Nutt. Blake (1939) listed this as a food plant, along with Beta vulgaris L., Chenopodium L. ( Amaranthaceae), and Sorghum bicolor (L.) Moench ( Poaceae). Probably these were all adult collection records; certainly, Sorghum is not a suitable larval host.

Biology. There are no published accounts of the larvae or leaf mines of Monoxia elegans . We found adults on Atriplex canescens plants with numerous abandoned mines, as well as a few containing dead larvae. Given the similarity of these to other Monoxia mines and larvae we have observed, along with the fact that all the adults we collected were M. elegans, we feel it is safe to attribute the mines to this species. The mines (Figs. 107–108) were full-depth blotches, some quite small and some occupying entire leaves. Frass was sparse, scattered in discrete, irregular pellets 1–4 times as long as wide. We did not find any mines containing pupal exuviae, so we believe that pupation was external, as observed by Eiseman (2014) with M. angularis (LeConte) and with all other Monoxia species we have reared. This is in contrast to Santiago-Blay’s (2004) statement that Monoxia larvae pupate inside their leaf mines.

Notes. Six species of Monoxia LeConte and three species of Yingabruxia Viswajyothi & Clark have been associated with Atriplex, but so far M. elegans is the only one specifically recorded from A. canescens (Clark et al. 2004; Santiago-Blay 2004).