INSECT VARIETY. 121 



" An attentive observation of the living insect invariably 

 reveals a perceptible motion o£ the palpi (Plate IV., Fig. 8, I), 

 the proboscis {s) — rolled up between them — at such times 

 remaining almost without movement. 



" The inner surface of either palpus towards its base is 

 naked, but when submitted to the microscope this seemingly 

 uniform glazed and shining surface is seen to be crossed by 

 numerous fine grooves composing an apparatus resembling in 

 construction the file of the burying, dung, and longhorn beetles" 

 (Plate IV., Pig. 4., /). 



Reaumur was the first who published an account of the note 

 of the Death's Head Moth, and he was fortunate in possessing 

 several living examples at one time, so that he was enabled as 

 much as possible to make a clear investigation. His conclusion 

 was the note of the moth might be produced " by the friction 

 of the two bearded limbs against the proboscis." In this case, 

 then, the two palpi carry the files, and the horny and short pro- 

 boscis lying between them acts the part of a clasp. 



" Since the files originate at the base of the palpi, the moth 

 is only dumb when these are totally removed. When the pro- 

 boscis is cut off the note naturally can be no longer effected, since 

 the surface of this organ on which the palpi rub is also removed. 

 If the files be rubbed against the proboscis each time, the note 

 of the insect is produced. The files of the males have finer 

 furrows than those of the females, which is in harmony with 

 the fact that the stridulation of the females is deeper than that 

 of the males." 



Dr. Landois then gives a table of the denticulation of the palpi 

 in seven Sphingina, and concludes the Death's Head stridulates 

 audibly, " because in this insect the teeth are very strong and 

 large." I may likewise add if one cuts off a palpus of a moth that 

 has been emitting its cry for some time, a further proof of the 

 implication of this part can be obtained, as the hair at its fore- 

 edge will present the appearance of being rubbed short, or worn 

 away. 



The Death's Head accompanies its squeak with a singular 

 phenomenon. As the male Hoopoe is said to call its vernal mate 

 by inflating its beak and then rapping it against the bark, so this 

 moth, as in mimicry, wdien it squeaks puffs out the first three 



