yune 20, 1872J 



NATURE 



153 



Finally, we find rome discussion of the matter in the En- 

 tomo/ixis/. Edward Newman (Eiitoiihi/ogist, August i S65, p. 2S4), 

 says, "With regard to the sound ]iroduced by the pupa and imago, 

 A vast deal has been written, but nothing worth repeating." 

 But he surely cannot have sufficient grounds for this sweeping 

 demolition of previous authors, and certainly cannot have con- 

 sulted this "vast deal which has been written ;" for he proceeds to 

 enunciate the very theory first put forth in the year 1755 by Rossel, 

 and subsequently revised by Duponchel in 1839. 



E. A. Johnson (J'.iilomo/ogist, Nov. 1S65, p. 325, Fic'i/ 

 newspaper, Oct. 24, 1S65) describes the organs discovered by 

 M. Lorey before the year 1S2S. and subsequently by Nordman, in 

 1S38. W. H. Taylor (/r/;/i'OT(i.'('^;>/j7, Nov. 20, 1S65) brings forward 

 Passerini's objection to Lorey's theory, viz , that males only have 

 these organs, while both sexessqueak, and that otherspecies which 

 produce no sound possess these organs. Thus does history repeat 

 itself. In the same page of the same journal we have some remarks 

 on the subject from the Rev. A. I'rcston, who, when sticking Ids 

 pin-point into an insect in killing it, and moving the pin up and 

 down against a muscle, heard a sound just like that of the mouth. 

 He docs not, however, from this observation draw any very 

 definite conclusion. 



It will be found that there are eleven distinct theories in all 

 which have been put forward to account for the cry of this moth. 

 I!y far the greater number attribute the phenomenon to friction 

 of various parts, two to an expiratory effort, one to rapidly 

 repeated percussion, and one to the inleivention of a fluid. 



The foregoing contains the pith of all the wriliogs on the sub- 

 ject which I have been able to meet with. I have no doub? 

 there are many others in existence, but I hardly expect that I 

 have missed any of importance. 



I am not aware whether all known species of Achtroutia emit 

 a sound; but a closely allied species in Ceylon is described by 

 Sir Emerson Tennant, in his " Natural History " of that island, 

 as doing so ; and I was lately, whilst in Ceylon, informed by 

 several residents that such was the case. This Ceylon species is 

 probably Sphinx Achcroiilia Lcl/u; described by Prof. Westwood 

 in his "Oriental Entomology," p. S7. 



I now pass to my own observations on the subject. I 

 was killing a specimen out of the large number which, as 

 stated above, I bred about six years ago, by means of a 

 solution of cyanide of potassium, which I was using with 

 a pen in the ordinary manner, the animal squeaking loudly 

 under the operation. A drop of the fluid happened to 

 fall on the extremity of the proboscis. I noticed that at each 

 sque.ak a large bubble was formed, showing a forcible expiration 

 from the organ. I repeated this experiment constantly with 

 water, and always with the same result. I further extended the 

 trunk with a pin during the emission of tlie sound, and noticed a 

 modification in the tone of the cry, which varied with the amount 

 of extension. These experiments convinced me that the sound 

 came from the proboscis, and was produced liy an expiration. 

 I at that time knew nothing of the literature of the subject, 

 and very little of anatomy, and I unfortunately made no further 

 observation or experiments in the matter ; and it was not till 

 last autumn that I was able to pursue the subject further on a 

 single specimen which I was fortunate enough to rear. This 

 specimen was a very lively one, and it squeaked freely. I placed 

 a tight ligature on the extremity of the proboscis whilst it was 

 in the act of emitting its cry. The noise stopped instantly. I 

 kept this specimen two days, and handled it constantly, bullying 

 it in all sorts of ways to try and get it to squeak, but without 

 result. After the proboscis had been thus ligatured for two 

 days, I amputated the lower portion of the trunk just above the 

 ligature. The animal instantly began squeaking, and continued 

 to do so at intervals for two days more, when I killed it in order 

 to examine the anatomy of its head. I fancied my experiments 

 at the time quite novel, and it was only the other day that I 

 found that similar ones had been made by Ghiliani and West- 

 maas ; but the method of ligaturing the proboscis, with subse- 

 quent amputation above the ligature, is, I think, more satisfac- 

 tory than Westmaas's use of wax. 



After these experiments, taken in confirmation of what 

 has already been done in the matter, I think there can be 

 no doubt that the sound is produced by expiration through 

 the proboscis. We have now to consider — How is this ex- 

 piration effected? Whence comes the air expired ? and Where- 

 abouts in the proboscis or head is the actual spot where the 

 sound is formed? I think it will be found that Passerlni's 

 explanation is in almost every respect satisfactory. I had no 



time to dissect my Death's Head whilst in the fresh state last 

 autumn, but preserved it in absolute alcohol. The accom- 

 panying drawing of a preparation made from it may therefore 

 need slight modification on further investigation ; but in the 

 main it will be found correct. The figure represents a magnifieil 

 view of a vertical section along the median line of the head. A 

 is the larjje dome-shaped cavity, evidently the one desciibed by 

 Passerini, and which R. Wagner could not find. This cavity 

 has a hard chitinous floor, which is prolonged forward so as to 

 project over the proximal extremity of the proboscis (seen here 

 in section with i's end amputated), and there ends in a sharp 

 edge, which forms, with the anterior wall of the cavity, a narrow 

 transverse slit, leading to the proboscis tube, just as described 

 by Passerini. Resting on the roof of the dome-.'-haped cavity 

 are Passerlni's muscles, L and C, with some cancellar-like tissue 

 between them and the external wall of the head. It would ob- 

 viously be easy to expose tfiese muscles as Passerini did with 

 great case and very Utile disturbance to the insect's functions, and 

 1 cannot see any reason to doubt that they would be found in 

 action just as he describes. 



Passerini does not figure the musLles or describe them accu- 

 rately. He merely calls them elevating and depressing muscles. 

 The muscle C must obviously on contraction raise the dome- 

 shaped cavity, whilst B must depress it. An alternate action of 

 the two muscles would cause the cavity to act as a bellows, and 

 inhale and expire air through that aperture which allowed it to 

 pass and repass most freely. Passerini believed that the air en- 

 tered the cavity by the o;sophageal opening at its hinder part, 

 which he describes as very narrow (lev. lif., p. 6) ("Da tutlo 

 cio che ha esposto credo poter concludere che I'aria dalli'nterno 

 della sfinge vien portata alia cavita muscolare della testa per 

 mezz5 deir esilissima tuba"), and was expelled then by the pro- 

 boscis ; but that this is really the correct explanation is scarcely 

 probable. First of all, the posterior opening into the cavity 

 must be very small indeed. I cannot find it at all in the present 

 specimen, and it is highly probable that it may often be aborted 

 altogether, as is the case in most butterflies. Moreover, how 

 should the air get into the cesophagus ? Certainly not from the 

 abdomen as supposed by Wagner, for Westmaas showed that the 

 animal could squeak after the abdomen was squashed out flat, and 

 Passerini himself showed that an insect would emit the sound 

 after it had been divided in two through the middle of the 

 thorax, an experiment which of itself is sufficient to overthrow 

 his own view. The opening into the proboscis being by far the 

 largest leading into the dome-shaped cavity, the air probably finds 

 ingress as well as egress by this aperture. And if I remember 

 rightly the bubbles formed on the end of the proboscis in my 

 experiments always collapsed between the squeaks, showing this 

 to be the case. I think that there can further be no doubt that 

 the note is formed at the narrow slit-like opening, the sound 

 being modified by passage through the proboscis tube, and by 

 vibrations therein set up, this latter to account for modifications 

 produced by straightening the trunk or by gradually removing it 

 bit by bit from below (Westmaas). 



I further think it probable that there is a movement of the 

 proboscis concerned in the production of the sound. If the base of 

 the proboscis were drawn a slight distance directly forward at each 

 inspiration, the upper opening of that organ would be brought more 

 immediately beneath the narrow passage communicating with the 

 dome-shaped cavity, and the ingress of air would be rendered 

 more free. Then if at expiration the base of the proboscis ^vere 

 retracted again, the aperture of egress would be very much con- 

 tracted, and the fomration of the sound facilitated. It would be 

 interesting to observe whether such a motion of the proboscis 

 takes place. I think I remember to have noticed a slight move- 

 ment of the trunk during the emission of the sound. 



It is most extraordinary that the seat of the sound should ever 

 have been imagined to be anywhere but in the head. One has 

 merely to listen to the animal to detect at once where the sound 

 comes from. It would seem as if many writers on the subject 

 had commenced their observations with a determination to find 

 some other seat for the cry. The animal is a large one, and one 

 could as easily persuade oneself that a mouse's cry proceeded 

 from the tip of its tail as that of a Death's Plead from its 

 abdomen. Should I obtain specimens of ,-/. atropos this autumn, 

 I hope to repeat Passerlni's experiments, and also make certain 

 whether inspiration as well as expiration takes place through the 

 proboscis ; I think also that Wagner's narrow slit on the under 

 surface of the proboscis should be experimented on. 



H. N. MOSELEY 



