Liriomyza Mik, 1894
A large genus with more than 300 (Spencer, 1986) described species, including some of the most serious pest species (L trifolii mine 2b.pct).
The stridulation organ between the tergites and sternites (figs: Li trifolii strid.pct, Li trifolii strid2.pct, Li trifolii strid3.pct) together with a scraper on the hind femur (Li trifolii tibia.pct) can be considered as the only apomorphic external character. However, this character is sometimes hardly visible especially in dry material and may require high magnification. For further details about stridulation organs in Agromyzidae (see von Tschirnhaus, 1972).
Zlobin, 1997 reported a very useful character of the male genitalia: The string-like basal part of the gonites is reduced or missing.
Liriomyza is closely related with the Genus Calycomyza but the latter can be recognized by the shape of the epandrium and the unique larval cephalopharyngeal skeleton.
Adults, external
The known economically important Liriomyza can be characterized by their yellow coloration on frons and scutellum (L trifolii adult3.pct). The character that should be checked for identification should be the presence of a stridulation mechanism. Finally the genitalia should be dissected. For species identification this work has to be done anyway. This feature also occurs in some other genera and there are also some economically not important Liriomyza with either the coloration at the frons or the scutellum lacking. The discal cell is present but normally smaller than in several other genera.
Male terminalia
Hypandrium long rounded below with thin hypandrial frame. Hypandrial apodeme absent. Epandrium normally short from side view, apically with a distinct sharp point (Lir chenopodii epandrium2.pct). Below the cerci the two wings of epandrium with a distinct inner wall ending before the tip. Surstyli normally present, always below the more or less pointed tip of epandrium and well separated from it (Lir xanthocera ep.pct). The surstyli normally with one or more spines or hairs at apex. Their number can vary among and within species. Gonites rather small, situated behind the surstyli, basal part reduced. Aedeagus with narrow and normally rather short basiphallus and normally with weakly sclerotized apical appendix. Distiphallus with basal bubble and a distal part of various forms, usually two terminal tubules visible. Apical part of the aedeagus often separated from the basal part by a hyaline intermediate section (Lir huidobrensis aedeagus.pct, Lir huidobrensis3 aedeagus.pct).
Ejaculatory apodeme can be of different size and shape, with sclerotized basal part.
Immature stages
There are no larval characters to identify any Liriomyza species unambiguously and easily. The following features may help to distinguish Liriomyza from leaf-mining Phytomyza and Chromatomyia species: Puparia almost always outside the mine, often yellow or light brown (L bryoniae puparia.pct). Larvae and puparia often only with three apical bulbs on each posterior spiracle (never in Chromatomyia and Phytomyza). Of these the hind bulb is somewhat elongated. Next to the spiracles often a spiracular sense organ can be found (Li pusilla p spiracle.pct). Bulbs of anterior spiracles are normally situated in one single row (unlike in Chromatomyia, rare in Phytomyza). Subspiracular processes below the posterior spiracles are widespread (missing in Chromatomyia and Phytomyza). The following pictures show SEM micrographs of the facial mask (Lir bryoniae Larva SEM1.pct) and the larval mouthhooks of a typical larva (Lir bryoniae Larva SEM2.pct). The larval mouthhooks are, alternating and of equal size. Cephalopharyngeal mostly without any peculiarities (Li bryoniae ceph.pct).
Bionomics
Most species, especially those causing any damage on crops, are leaf miner (L trifolii mine.pct). However, there are some seed feeding species and species mining in the "stems" of horsetails. The type species Liriomyza urophorina feeds on the stems of Lilium. Pupariation normally takes place outside the mine. Parrella, 1987 reviewed the biology of the economical important Liriomyza species.
Economical importance
There are many species causing serious damage on various pests, of these some truly polyphagous species introduced in almost all zoogeographical regions. They belong to the most serious pests within the agromyzid leaf miners (Minkenberg and van Lenteren, 1986, Parrella, 1987).