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Mechanoreceptors that could be phonoreceptive were located and studied in Sitophilus oryzae (L.), with preliminary tests also on Sitophilus granarius (L.). Tribolium confusum (Herbst), Attagenus piceus (Olivier), and Trogoderma inclusum LeC. Various behavioral responses of tethered (mounted) beetles were used as indices of reception of air-borne and solid-borne sounds of known frequencies and pound pressure levels. The probable receptors for air-borne sounds in S. oryzae are the well developed Johnston's organs in the second antennal segments, and tactile hairs on the bodies. Both are primarily sensitive to air movements or contact, and sounds are active only at relatively high intensities or in the near-field. The probable receptors for solid-borne sounds (vibrations) are chordotonal organs of the legs, which have relatively high sensitivity, and possibly the muscle receptor organs of the body wall. These four potential phonoreceptors are described and figured. The low sensitivity to air-borne sounds and high sensitivity to solid-borne sounds is probably related to the specialized habits of these insects.

Rejection thresholds for HCl, CH3COOH, NaOH, NaCl, NH4Cl, KCl, CaCl2, and LiCl, presented as drops of solutions on leaves of the food plant, were determined for caterpillars of the cecropia moth, Samia cecropia. Rejection thresholds for glucose, sucrose, lactose, and strychnine sulfate either do not exist under these conditions, or are higher than the saturation concentrations of solutions of these substances. The lowest threshold of those tested is that for HCl, but CH3COOH has greater stimulative efficiency when it is compared with HCl at the same pH. The threshold for NaOH is higher than that for HCl, indicating that the OH– ion is less stimulating than the H3O+ ion. The order of stimulative efficiency for the cations, as chlorides, is NH4+ = K+ > Ca++ > Na+ > Li+. This is the order of ionic mobilities to which the stimulative efficiencies seem to be related. No conclusions can be drawn with certainty as yet regarding the modalities of taste for these animals.

The upper limit of hearing (ultrasonic limit) has been determined with reasonable accuracy for only fourteen species of birds; in general, it lies between 12,000 and 20,000 cycles per second (Schwartzkopff, 1955a, 1955b; 1956; Frings and Slocum, 1958). Schwartzkopff (1955a) alone, using electrophysiological methods, has reported responses of the ear above 20,000 c.p.s. It would seem fair to conclude, therefore, that the hearing ranges for birds do not generally extend to higher frequencies than those for man. The frequencies of greatest sensitivity seem, as for man, to be from about 1000 to 5000 c.p.s. The audiograms of the very few species of birds that have been studied seem to rise more steeply above 5000 to 6000 c.p.s, than does the audiogram of man (Schwartzkopff, 1949, 1952; Heise, 1953; Schleidt and Schleidt, 1958). As Schwartzkopff (1957) has pointed out, however, the data necessary for secure generalizations about hearing in birds remain to be gathered. The present paper reports information on the upper limit of hearing for the European Starling (Sturnus vulgaris). The ultrasonic limit for this bird has been reported by Brand and Kellogg (1939) to be about 15,000 c.p.s. and by Trainer (MS, thesis Cornell Univ.) to be about 10,000 c.p.s. The last figure is almost certainly too low and may have resulted from the nature of the sound system used. The results here presented are a contribution to this neglected field of avian physiology. They may have further interest because of the appearance of a phenomenon not previously noted in tests on hearing in birds. These studies were made while the authors were at the Pennsylvania State University.

Abstract Albino mice from a stock produced by nine generations of selection for high incidence of clonic-tonic seizures but low incidence of deaths in seizures were tested for susceptibility when started at 20, 25, 30, or 35 instead of the usual 15 days of age. There was a sharp decrease in susceptibility to clonic-tonic seizures and an increase in variability of response when the mice started at 25 days of age or later. When mice of the same stock which had had seizures regularly before 50 days of age were tested after 50 days of age they continued susceptible until death or near death, even when the life-span was relatively long. Offspring of crosses between mice of this stock and those of a stock selected for low seizure incidence had an average seizure incidence intermediate between those of the parent stocks, but no simple genetic explanation could be postulated. Mice of the high incidence stock which were mated without being tested for two generations produced offspring with decreased susceptibility, but still with a high proportion of individuals highly susceptible. These results show the necessity for standardization of stocks of mice and testing procedures in studies on audiogenic seizures. They support the view that inheritance of seizure susceptibility is multigenic and quantitative.

1. The effects of temperature on the sucrose thresholds of the tarsal chemoreceptors of the flesh fly were studied. Flies were mounted on rods and the thresholds determined in a constant temperature chamber at 19-21° C., 27-29° C. and 37-39° C.2. A total of 748 flies (313 males and 435 females) were subjected to 8241 tests.3. The median threshold at 19-21° C. was 0.14 M, at 27-29° C. was 0.06 M, and at 37-39° C. was 0.17 M.4. On the basis of these data, no definite stand can be taken on the limiting mechanism of tarsal chemoreception.

That some species of moths produce and receive sounds is now well established. Reaumur (1734, pp. 294-295; 1736, pp. 289-293) first called the attention of scientists to the sound produced by the Death's Head Moth, Acherontia atropos. Many papers on the sounds produced by this and other species of moths have since appeared (cf. Swinton, 1880, pp. 118-127; 205-206 for review of earlier work; Frings, 1955 for refs. to lit.). Moths are also known to receive sounds by means of an auditory organ first described by Swinton (1877, 1880, pp. 243-249). Experimental studies on sound reception by moths and the physiology of the tympanum have been fairly numerous also (cf. Eggers, 1925, 1928 for review of earlier work, Kennel and Eggers, 1933,. Schaller and Timm, 1949, 1950, and Treat, 1955 for more recent studies).

The pinnae of white mice, when exposed to high intensity airborne sound waves, exhibit an immediate inflammation followed by degeneration. Treated pinnae were compared histologically with normal pinnae, with pinnae treated with high temperatures, and with pinnae of mice which were depilated around the ears and treated with sound so that no heat could be produced by absorption of sound in the fur. The results showed that the major factor in destruction of the pinnae is heating in the fur, but some of the effects produced by sound are probably the results of mechanical agitation or a combination of heating and mechanical agitation.

The published literature on production and reception of sounds and acoustical behavior of beetles of eleven families and moths of two families that include important stored products pests is reviewed. Little is known directly on the pest species, but studies on related species suggest that the pests may have acoustical reactions that could form the basis for control. Except for one promising study on Plodia interpunctella , no critical attempts have been made to control stored products pests with sound.

1. The loci of contact chemoreceptors, stimulation of which by sucrose solutions elicits proboscis extension, were determined for the butterflies: Cercyonis pegala and Lethe eurydice of the Satyridae, and Speyeria cybele and Limenitis arthemis of the Nymphalidae; and the diurnal moths: Ctenucha virginica and Scepsis fulvicollis of the Amatidae.2. Local contact and excision methods were used. All have the receptors on the terminal part of the proboscis and on all the functional tarsi. The palpi probably do not bear the receptors, and in the butterflies the antennae likewise. In Ctenucha removal of the first two pairs of legs and in Scepsis removal of all the legs resulted in feeding reactions on stimulation of the antennae with sucrose solutions.3. These results emphasize the need for careful control and specification of testing conditions and for cautious interpretation of negative results in experiments such as these.

Albino mice were tested for susceptibility to audiogenic seizures in sound fields of various frequencies and intensities. An attempt to fix the ears of the mice with respect to the sound source by suspending the mice with a large spring clip which grasped the dorsal skin‐fold proved fruitless, for too few seizures were induced at any intensity. The mice were therefore tested in a small wire mesh cage suspended in front of the sound‐transducer, and the positions of their ears during the treatment were recorded. At 10 kc, at least 92 db was needed to induce seizures in mice which had no previous seizures, while only 83 db were needed for animals which had previous seizures. The most effective frequencies for the induction of seizures were between 12 and 25 kc. Below 10 kc, the effectiveness dropped off sharply and was very low at 5 kc. Studies were not made above 25 kc. The peak of the mouse's audiogram is probably near the frequencies which are most effective for induction of seizures and is thus a little lower than that of the rat and about 1.5 octaves above that of man. The ability of mice to hear at frequencies which are ultrasonic for the human ear is probably the reason for the intense reactions of mice to complex sounds which seem of moderate intensity to man.

The loci of contact chemoreceptors sensitive to sucrose and NaCl in solution and mediating feeding responses were determined experimentally in adult Trichoptera of four species from the families, Phryganeidae and Limnephilidae. The receptors are on the ventral surfaces of all the tarsi, the tips of the maxillary and labial palpi and the haustellum. The animals feed on liquids, and these receptors allow them to distinguish acceptable from non-acceptable materials in solution. Less precise observations on two other species from two other families showed a similar situation in these. The end-organs are probably trichoid sensilla. This fact, along with the presence of tarsal contact chemoreceptors, places adult Trichoptera of these species, at least, among typical haustellate insects, most nearly resembling many Diptera in locations of the receptors and feeding reactions.

Swarms, consisting apparently of males only, respond to simple sounds produced by an audio-oscillator through loud speakers. A startle response occurs when sounds between 80 and 800 cps are broadcast to the swarms at intensities above about 80 db. A second response, an agitated circling and gathering around the sound source, occurs only near 125 and 250 cps, at intensities of 13–18 db. above ambient noise levels for 125 cps, and 3–8 db. for 250 cps. The second reaction, because of its sharply tuned frequency determination and occurrence at remarkably low intensities, could have significance in mating or swarming. The frequency of the male wing sound is about 600 cps, and broadcasts of recorded samples of this to the swarms had no effect. No females were captured at any time; thus the frequency of the female wing sound is unknown. The possible biological significance of the reaction was not determined.

Sea-hares, Aplysia juliana, when hungry, are aroused to activity by and oriented toward Ulva lactuca, their normal food. The same response occurs when the animals are stimulated by sea water in which Ulva has stood for a few minutes. The material given off by the Ulva is non-volatile, heat-stable, and remains in the water fraction after ether extraction. The receptors for this substance, when it acts in arousal and orientation, are on the tentacles, but not on the rhinophores. When sea water in which Ulva has stood is dropped onto the mouth of an aplysia, the animal starts feeding activity. The stimulating material acts at very low concentrations and is strongly excitatory. Normally these aplysias eat only the terminal thin parts of Ulva and leave the coarser bases which produce new blades. This may be due to the absence of phagostimulant in the bases. The animals therefore do not eliminate the Ulva, even when they are very numerous, and their food supply is thus maintained.

A standard terminology is suggested for the behavioral sequences in audiogenic seizures of mice. Two kinds of latent period, three phases of the seizure and three intergrading types of convulsion are distinguished.

Es konnte festgestellt werden, das Katzen die Geschmacksempfindung «sus» nicht besitzen. Sie konnen aber «sus» von «nicht sus» unterscheiden. Elektrophysiologisch last sich dieser Befund nicht belegen. Zur Erklarung wird auf die Geschmacksspektrum-Theorie verwiesen.

WHILE visiting our laboratory, R.-G. Busnel of France directed our attention to a brief note by Pasquinelly1 on making visible the magnetically oriented areas on tape recordings by immersing the tape in a viscous liquid suspension of ferromagnetic powder and draining off the excess. We have found a modification of this method useful for studying sounds of animals recorded on magnetic tape. Immersion proved unsuitable, because it did not produce clear patterns, and the recorded tapes were difficult to clean afterward.