266 TEXT-BOOK OF ENTOMOLOGY 



as organs of smell a view which, as regards the antennae, was opposed by 

 Newman. 



Thus the contention as to the use of the antennae and the seat of the organs 

 of smell and hearing fluctuated from one side to the other, and when in 1844 

 Ktister, by reason of his experiments on numerous insects, again claimed that 

 "the antennae are the smelling organs of insects," he argued on a scientific 

 basis; yet v. Siebold and Stannius (1848), in their valuable Lehrbuch der 

 vergleichenden Anatomic (p. 581), remarked that "organs of smell have not yet 

 with certainty been discovered in these animals." 



The following decennial was of marked importance in the judgment of many 

 disputed questions. Almost contemporaneously with Siebold and Stannius' 

 Lehrbuch appeared an opportune treatise by Erichson, in which this naturalist 

 first brought forward certain anatomical data as to the structure of the antennas 

 of insects. In a great number of insects Erichson described on the upper sur- 

 face of the antennae peculiar minute pits, "pori," which, according to him, 

 were covered by a thin membrane, and to which he ascribed the perception of 

 smell. A still more thorough work on this subject was published in the follow- 

 ing year by Burmeister, who recognized in the pits of lamellicorns many small 

 tubercles and hairs ; and about the same time Slater, as also Pierret and Erich- 

 son before him had done, out of the differences of the antennal development in 

 the males and females in flesh and plant-eating insects, brought together the 

 proof of the olfactory function of the antennae. But the most valuable work of 

 this period is that of Ferris, who, after a review of previous opinions, by exact 

 observations and experiments, a model of their kind, sought to discover the 

 seat of the sense of smell. He comes to the conclusion that the antennae, and 

 perhaps also the palpi, may claim this sense, and finds full confirmation of 

 Dufour's views, and adopts as new the physiological possibility expressed by 

 Hill and Bonnet, that the antennae might be the seat of both senses those of 

 smell and hearing. 



The beautiful works of Erichson, Burmeister, and Ferris could not remain 

 long unnoticed. In 1857 Hicks published complete researches on the peculiar 

 uerve-endings which he had found in the antennae, also in the halteres of flies 

 and the wings of all the other groups of insects, and which he judged to be for 

 the perception of smell. But Erichson's and Burmeister's "pori" were by 

 Lespes, in 1858, explained to be so many auditory vesicles with otoliths. This 

 view was refuted by Claparede and Glaus without their deciding on any definite 

 sense. Leydig first made a decided step in advance. In different writings this 

 naturalist had busied himself with the integumental structures of arthropods, 

 and declared Erichson's view as to the olfactory nature of the antennal pits as 

 the truest, before he, in his careful work on the olfactory and auditory organs of 

 crabs and insects, had given excellent representations of the numerous anatomi- 

 cal details which he had selected from his extensive researches in all groups of 

 arthropods. Besides the pits which were found to exist in Crustacea, Scolo- 

 pemlne, beetles, Hymenoptera, Diptera, Orthoptera, Neuroptera, and Hemip- 

 tera, and which had only thus far been regarded as sense-organs, Leydig first 

 calls attention to the widely distributed pegs and teeth, also considering them as 

 sense-organs. "Olfactory teeth," occurring as pah- rods, perforated at the end, 

 on the surface of the antennae of Crustacea, Myriopoda, Hymenoptera, Lepidop- 

 tera, Coleuptera, are easily distinguished, and besides the "olfactory pegs" of 

 the palpi, may be claimed as organs of smell. The nerve-end apparatus first 

 discovered by I licks in the halteres and wings, Leydig thinks should be ranked 

 as organs of hearing. 



'Ihere was still some opposition to Leydig's opinion that in the insects the 



