Ancistrocerus gazella is a species of potter wasp. The female of the species collects as many as 20 caterpillars for each nest, which consists of a single cell which is a tube made out of mud. Her larval offspring then feed on these inside the nest, which is sealed with mud. As adults, they eat nectar and aphid honeydew. Males cannot sting, and the sting of a female is not painful. They can be found on windows, foraging for nectar on flowers, or searching out small cracks or holes in which to build a nesting tube.
The species became established in Auckland, New Zealand in 1987, and is now found even in Otago (near the country's southern extremity).
The following is its description is from New Zealand Entomologist, 1989, Val. 12 63
Titled Ancistrocerus gazella (Vespoidea: Eumenidae); the first record
for New Zealand, By J. A. Berry, Entomology Division, DSIR
“ Female: 11-15 mm. Head transverse, black with yellow markings on clypeus, between antennal sockets and a yellow genal spot. Eyes deeply emarginate opposite antennal sockets. Antennae black, slightly clavate; ventral side of scape yellow. Thorax black.with yellow pronotal collar widened at each end. Lateral angles of pronotum sharply pointed.
Tegulae and pleural spot yellow. Mesoscutum black, coarsely punctured; scutellum yellow marked. Metanotum with or without yellow markings. Abdomen black with yellow bands on tergites 1-5, that on TI rectangularly emarginate anteriorly. Femora black proximally, yellow distally. Tibiae yellow, tarsi brownish-red.
Male: 7-9 mm. Yellow markings as for female except for clypeus entirely yellow, more convex than female. No pleural spot, scutellar markings much smaller and no markings on metanotum. Distal 2 segments of antennae reflexed.”

Female
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Female
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Female
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Female
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The head of a female Ancistrocerus gazelle

A male wasp.(dead specimen)
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Male
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Male

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Wasp (European tube) Ancistrocerus gazella