Recently I came across a flying insect about 21/2 inches long, its abdomen was three-quarters black and the rest yellow. Its main feature was a stick-like appendage protruding from it tail. John Minihan, Union Hall, Co Cork
Please identify the enclosed insect. Is the rear protrusion a sting or an ovipositor? John J. Walsh, Moate, Co Westmeath
The answer to both queries is the horntail, also called the wood wasp, which is a 4 cm-long sawfly and not a wasp. The female has a long ovipositor in a yellow sheath which she uses like a drill to bore holes in conifer trees, in which she lays her eggs. The larvae take two or three years to mature before they emerge as winged adult. The male is rarely seen as he usually flies above the canopy of conifers.
Edited by Michael Viney, who welcomes observations sent to him at Thallabawn, Carrowniskey PO, Westport, Co Mayo. e-mail: viney@anu.ie. Observations sent by e-mail should be accompanied by postal address as location is sometimes important to identification or behaviour.