its efforts, and little by little penetrates the hole. As may be seen, the labour is laborious and painful, and may present itself beneath various aspects which call for a certain ingenuity on the part of the animal. [75] Reaumur, _Memoires pour servir a l'histoire des Insectes_, Paris, 1742, t. vi., pp. 282-284. Up to recent years the _Cerceris_ was considered to act with as much certainty as the _Sphex_, and to obey an infallible instinct which always guided it for the best in the interests of its offspring. The insects it attacks belong to the genus _Buprestis_. It consumes them in considerable numbers. Its manner of action, as described by Leon Dufour,[76] much resembles that of the _Sphex_, and it would be superfluous to describe it. The only fact which I wish to mention, and which has been put out of doubt by the illustrious naturalist, is this: the _Buprestis_ are paralysed, not dead; all the joints of the antennae and legs remain flexible and the intestines in good condition. He was able to dissect some which had been in a state of lethargy for at least a week or a fortnight, although, under normal conditions, these insects in summer decay rapidly, and after forty-eight hours cannot be used for anatomical purposes. Another observer, Paul Marchal, took up this question afresh, and the results which he obtained seemed to indicate an instinct much less firm than earlier studies tended to show.[77] [76] "Histoire des _Cerceris_," _Ann. Sc. Nat._, ii. Serie, t. xv., 1841, pp. 353-370. [77] _Arch. de Zool. exp._, 1887.