126 IIYMENOPTERA 



CHAP. 



It has long been known that some species of Cerceris prey on 

 bees of the genus Hal ictus, and Marchal has recently described 

 in detail the proceedings of C. ornata. This Insect catches 'a 

 Halictus on the wing, and, holding its neck with the mandibles, 

 bends her body beneath it, and paralyses it by a sting admin- 

 istered at the front articulation of the neck. The Halictus is 

 subsequently more completely stunned or bruised by a process of 

 kneading by means of the mandibles of the Cerceris. Marchal 

 attaches great importance to this " malaxation " ; indeed, he is of 

 opinion that it takes as great a part in producing or prolonging 

 the paralysis as the stinging does. Whether the malaxation 

 would be sufficient of itself to produce the paralysis he could not 

 decide, for it appears to be impossible to induce the Cerceris to 

 undertake the kneading until after it has reduced the Halictus 

 to quietude by stinging. 



Fabre made some very interesting observations on Cerceris 

 tnlerculiita, their object being to obtain some definite facts as to 

 the power of these Insects to find their way home when removed 

 to a distance. He captured twelve examples of the female, 

 marked each individual on the thorax with a spot of white 

 paint, placed it in a paper roll, and then put all the rolls, with 

 their prisoners, in a box ; in this they were removed to a distance 

 of two kilometres from the home and then released. He visited 

 the home five hours afterwards, and was speedily able to assure 

 himself that at any rate four out of the twelve had returned to 

 the spot from whence they had been transported, and he enter- 

 tained no doubt that others he did not wait to capture had been 

 equally successful in home- finding. He then commenced a second 

 experiment by capturing nine examples, marking each with two 

 spots on the thorax, and confining them in a dark box. They 

 were then transported to the town of Carpentras, a distance of 

 three kilometres, and released in the public street, " in the centre 

 of a populous quarter," from their dark prison. Each Cerceris 

 on being released rose vertically between the houses to a sufficient 

 height, and then at once passed over the roofs in a southerly 

 direction the direction of home. After some hours he went 

 back to the homes of the little wasps, but could not find that 

 any of them hail then returned; the next day he went again, 

 and found that at any rate five of the Cerceris liberated the 

 previous day were then at home. This record is of considerable 



