Fenusa

A genus of around fifteen species with a holarctic distribution. In Britain and Ireland the Fenusa are represented by four species in two subgenera. It should be noted that some authors elevate the subgenera to genus level.

The subgenus Fenusa can be characterised within the Fenusini by the following features. The antennae are nine segmented with the third segment longer than the fourth and the pedicel about as long as it is broad. The malar gap is less than the diameter of the front ocellus. The post-genal carina and the prepectus are both absent. In the forewing, the anal cell is complete with a small basal portion. Vein 2r joins RS distal to 3rm. The hind wing venation is simple with no enclosed cells. On the hind legs, the fourth tarsomere is strongly, apically produced beneath the fifth. The tarsal claws are simple. On the fore and middle legs, the tarsi are similar in length to their corresponding tibiae. Larvae feed inside blister mines in the leaves of members of the Betulaceae family and shrubby members of the Rosaceae.

The subgenus Kaliofenusa can be characterised within the Fenusini by the following features. The antennae are eight or nine segmented with the third segment longer than the fourth and the pedicel about as long as it is broad. The malar gap is less than the diameter of the front ocellus. The post-genal carina and the prepectus are both absent. In the forewing, the anal cell is complete with a small basal portion. Vein 2r joins RS before 3rm. The hind wing venation is simple with no enclosed cells. On the hind legs, the fourth tarsomere is strongly, apically produced beneath the fifth. The tarsal claws are simple. On the fore and middle legs, the tarsi are similar in length to their corresponding tibiae. Larvae feed inside blister mines in the leaves of members of the Ulmaceae family. It should be noted that Kaliofenusa species show little difference in morphology or genetics and may be considered as a single species under the name Kaliofenusa pusilla.

Species list:

Fenusa (Fenusa) dohrnii (Tischbein, 1846)

Fenusa (Fenusa) pumila Leach, 1817

Fenusa (Kaliofenusa) altenhoferi Liston, 1993

Fenusa (Kaliofenusa) ulmi (Sundevall, 1847)

References:

Benson, R.B., 1952. Handbooks for the Identification of British Insects. Hymenoptera, Symphyta, Vol 6, Section 2(a-c), Royal Entomological Society, London

Liston A, Knight G, Sheppard D, Broad G, Livermore L (2014) Checklist of British and Irish Hymenoptera - Sawflies, ‘Symphyta’. Biodiversity Data Journal 2: e1168. https://doi.org/10.3897/BDJ.2.e1168

Smith, D. R. 1971: Nearctic Sawflies. III. Heterarthrinae: Adults and larvae (Hymenoptera: Tenthredinidae). - Technical Bulletin, U.S. Department of Agriculture, Washington 1420: 1-84

Smith, D. R. 1976: World genera of the leaf-mining sawfly tribe Fenusini (Hymenoptera: Tenthredinidae). - Entomologica scandinavica, Copenhagen 7: 253-260

Smith, D. R. 1981: Studies of the leaf-mining sawflies of the tribe Fenusini in Asia (Hymenoptera: Tenthredinidae). - Proceedings of the entomological Society of Washington, Washington 83(4): 763-771

Smith, D. R.; Altenhofer, E. 2011: The second record of a sawfly leafminer on Rosa, a new species of Fenusa (Hymenoptera: Tenthredinidae). - Proceedings of the entomological Society of Washington, Washington 113(1): 57-60.