Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 52. (Budapest 1960)
Móczár, L.: The loess wall of Tihany and the nesting of Odynerus spiricornis Spin. (Hymenoptera, Eumenidae)
was only one and a half meters from my vantage point, assuring a complete survey of the whole wall. And it is impossible not to perceive a larve-carry ing wasp due to its sluggish flight and the green sawfly larve lugged under its abdomen. Odynerus Nr. 5. This specimen gnawed a small hollow at 12 : 22 on 21 July. During its absences for water, I hollowed twice the wetted place with my pincers. The wasp continued undisturbed its work after it returned to the nest. Odynerus Nr. 9—14. The wasps observed on 21 July (but their activities not discussed in details here) excavated burrows as long as their bodylength during 2 hours and 15 minutes ; that is, they erected in front of the (at least) 10 mm deep burrow a turret of 4—5 layers of small mud pills so that their bodies have disappeared within. Their constructing work continued also on the next day. One of the daubers (Nr. 14.) departed twice toward the Balaton between 10 : 42—11 : 03, it also discarded pills twice, and increased its turret by 7 pills. Then it flew away, and returned only at 12 : 40. Odynerus Nr. 18. It began the scraping of its nest at 16 : 20 on 22 July, and soon it erected a small ledge at the base of the concavity. In spite of the harder, sedimentary substratum, the turret rose to a height of 24 mm till 6 p. m., the length of the whole burrow being 67 mm. Odynerus Nr. 15. It began excavating its final nest at 11 : 25 on 22 July. Though it was flying somewhat further away around 13 : 00, it was still working on the erection of the turret after 3 p. m. It appeared again before the loess wall at 10 : 35 on 23 July, flying around for a short time, and then disappeared. It was digging again between 14 : 30—15 : 20, building the turret. At 13 : 10, it appeared in the entrance of the turret, turned around outside, and climbed in backwards. It is obvious from what was said before that Odynerus spiricornis softens with water the loess wall or the lower lying sedimentary layer before attacking them with its mandibles (Plate II, fig. 3). It brings the necessary water from the Balaton in an average time of 5 minutes. It sucks up the w r ater on the shore of the lake, from the stones wetted by the small wavelets. The carrying of the water takes about one minute. The amount of water carried by it is sufficient for the excavation, that is, for the kneading of 5 pills. It excavates and carries out the pills in about 23 seconds, and pastes them to the edge of the turret in an average time of 10 seconds. It probably also wets the pills a bit before pasting them to the turret, and that is why they adhere so closely, and merge into, each other. After desiccation, the flattened, uneven bits of the several mud pills are well visible on the external sides of the turret (Plate II, fig. 5—6 ; Plate III). However, the interior of the turret is completely smooth. Namely, when the wasp carries up the pill between its mandibles and puts it on the rim of the turret, it assumes a peculiar position. It arches in a circle, its back downw r ards (toward the inside of the turret), its abdomen turning up toward its chest (Plate II, fig. 5). Its flat forehead touches the inner side of the turret. It clings, that is, supports itself with its anterior and median legs and mavbe its wings. And while it smooths the pill with its flat forehead to a concave shape on the inner side of the turret, it keeps back with its posterior legs the pill on the outer side of the turret (Plate II, fig. 6), so that it should not fall down, drawing it inside with its legs in the meantime, toward its head. The mud pill desiccates and binds quickly on the hot sun (about 40° C). The opposing movements of the forehead and the posterior legs of the wasp work in utter harmony ; I saw it only once during a whole week that the mud pill fell down on the outer side of the turret (pill 5. of section
