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)
flew off again at 12 : 43, but in 54" it was digging in a lowerdying small hollow, scraping its material over into the former burrow. Then it was scraping the uneven, projecting parts of the adjacent area again. It flew away at 12 : 46, leaving its excavated pill in the middle of the hollow, and continuing its scraping work in 55" again. At 12 : 49, it was hovering above a fresh place, searching for a suitable nesting site. Odynerus Nr. 8. This specimen was digging a small hollow in the loess wall at 12 : 55 on 21 July. At 13 : 00, it finished with a small hollow, of a largely horizontal base with a partly constructed small rim (Plate II, fig. 4). Between 13 : 02 and 13 : 31, it flew away 19 times for one or two minutes (an average 1,6 minutes), returning generally in 40 seconds. At 13 : 31, the excavated place developed, against the customary formation, into a trough elongated in a perpendicular direction, open also on its lower side. Six other wasps (Nr. 9—14), digging in the vicinity, constructed a low ledge (from the excavated material) on the inferior portion of their incipient nests. Wasp Nr. 8. left this place at 13 : 32, flying about at a lower level, entering two alien burrows and turrets. At 12 : 40 on the next day, it was still searching for a nesting place one and a half inches below the initial and abandoned wall portion of the twentyfirst July. Odynerus Nr. 15. After I broke up its cell finished on 21 July (cf. p. 399), it was flying before the loess wall at 10 a. m. on 22 July. At 10 : 35, a 6 mm deep hollow indicated the fact that it began to construct its nest in the lower, sedimentary layers. However, it had left it later, working on a fresh one at 10 : 55. It left this one too, commencing its final construction at 11 : 25 (cf. p. 392.). The selection of the place of the nest always requires a shorter or longer period. Generally, the wasps begin the building of the nest after some hours, but they will not infrequently grope around the different parts of the wall for several days (Plate II, fig. 3), prying every now and then into the hollows or even into the turrets. Some wasps will change over from the softer loess wall parts to the harder, sedimentary layer. They may leave their portion of the wall equallv in wholly open or in densely settled areas. Their uncertainty therefore cannot be caused by the different hardness of the substratum, or by the presence of cells in its depth. I endeavoured to observe their activities motionless and from far off, and thus the observing person could not have disturbed their work. The long-w inded selection of the nesting place is therefore not dependent on the so-called ,,carefulness" or ,,thoroughness" of the wasps ; it can best be explained by the weakness of the instinct directing their activities, wherein external stimuli will still stronglv influence their behaviour. Nest building Odynerus Nr. 3. It began digging its final nest at 13 : 50 on 21 July (Plate II, fig. 4). Before long, it gnawed a 1,6 cm deep, downwards curving passage in the vicinity of a broken up nest. It. flew away and returned at 15 : 21, then it took to wings again and reappeared in 58 seconds. Its burrow was then of equal length with its body. Then it flew aw r ay again at 15 : 26, nor did it return till 6 p. m. on this day. On 22 July, it appeared at 10 : 40, continuing the excavation of the nest. The passage was 40 mm long at 11 : 15, of which the turret made up 14 mm. Then it flew away, returning in 55". The further construction of the turret on this day was indicated by two layers of fresh, wet pills. It flew away in the direction of the Balaton at 11 : 18,30", returning after 40". Now it was scraping the upper part of the slightly sloping burrow, with only the end of its abdomen coming occasionally to light, from its dorsal or abdominal side. It took to wings again towards the shore at 11 : 23,50", returning after 45" and continuing its work in the burrow. Then it daubed the material, wetted and excavated from the inside of the burrow, as 5 pills onto the turret. It left again at 11 : 28,17", appearing after 62". It daubed the interior of the burrow for 1/15", then pasted two pills onto the turret. For the sake of an easy survey of the turret-constructing work of the wasp, I present the further details mainly in figures (fig. 2—5). The large circles
