Napomyza Westwood, 1840
Spencer, 1990 (p. 37) divided the genus into two groups, the ranunculella- and the lateralis-group. In the former group, the plesiomorphic condition of two distinct terminal tubules of distiphallus is still present. However, the concept of the genus is still a matter of debate: Zlobin, 1994 created another genus concept and transferred the second group with distinct terminal tubules to Genus Phytomyza. This, however, will have no implications for the species treated here. Further revisionary work has to be done to clarify the status of Napomyza and the allied taxa Genus Phytomyza and Genus Chromatomyia.
On this CD-ROM only members of the lateralis-group are included.
Diagnosis (only applicable to the species on this CD-ROM (lateralis-group):
Distiphallus thin and elongated, not obviously bifid; sclerotization of mesophallus reduced, not forming a cylinder; 'paramesophalli' (paraphalli, side sclerites of basiphallus) well-developed (Griffiths unpubl.). Crossvein m-m present but strongly shifted towards the wing base (wing N lateralis.pct).
Additional characters found in other genera as well:
Orbital setulae proclinate; costa extending only to R4-5 (as in Phytomyza and Chromatomyia). Body with extensive yellow sections, but dark scutellum.
Immature stages
Larvae live in leaf petioles, leaf veins, stems, roots, flower heads or seeds. Napomyza cichorii can be found within the basal sections of leaves and leaf veins of lettuce. The pre-imaginal stages of Napomyza in cultivated plants can be distinguished from other stem and seed miners by the combination of the following characters.
1. Pupariation within the host plant
2. Puparium white or light brown, thickest part just behind the third segment, the segments behind are tapering Nap cichorii puparium.pct.
3. Dorsal wing of cephalopharyngeal skeleton simple (not consisting of conspicuous upper and lower parts as in Agromyzinae (cf. agr-phy-larva.pct).
4. On each posterior spiracle always more than three bulbs.
5. Larval mandibles enlarged, right mandible larger than left.
6. Mandibular complex with long and narrow lateral sclerite Nap lateralis ceph.pct.
Remark
The Napomyza species are difficult to identify; even the genitalia of different species can be extremely similar. Whenever possible, larger series of specimens should be compared.
Bionomics
As already mentioned, Napomyza larvae are mainly stem and seed miners of various plants.