430 Miscellaneous. 



if these apeitures are stopped with bird-lime the sharp sound con- 

 tinues to be produced with the same intensity. 



Its origin must be sought in the mechanism b)^ which the wing is 

 Bot in motion. In buzzing insects the muscles of flight are not in- 

 serted directly upon the wing, but upon the pieces of the thorax which 

 carry it. It is the movement of these that moves the wing and 

 makes it vibrate. The thorax therefore undergoes alternate and 

 incessant changes of form under the influence of the contraction of 

 the motor muscles of the wing : in repose a section of this region 

 represents an ellipse elongated vertically ; muscular action trans- 

 forms it into an ellipse elongated laterally. The entire thorax 

 therefore vibrates successively in the direction of its two diameters. 

 As the muscular masses are very powerful, this vibratory movement 

 is very intense, as we may easily ascertain by holding between the 

 fingers a Humble-bee with its wings cut off", but which still seeks to 

 fly away. The thorax consequently forms a vibrating body, which 

 directly concusses the surrounding air, just in the same way as the 

 branch of a diapason for example. In the insects in question tho 

 vibrations are repeated a great number of times per second, and 

 there is produced a musical sound which is nothing but tho sharp 

 Bound characteristic of buzzing. Large insects produce the sharp 

 sound with more intensity than small ones, because the vibrating 

 surface of the thorax in contact with the air is more extensive. 



If the thoracic sound, after the cutting away of the wings, is 

 higher than the sound produced directly by the movement of the 

 latter, this is because, during flight the resistance of tho air mode- 

 rates the velocity of contraction of the muscles ; while, when the 

 wings are suppressed, the muscles, vibrating without producing any 

 useful effect, attain their maximum velocity. 



After the removal of the wings, by attaching a style to the upper 

 wall of the thorax, we may directly inscribe its vibrations ; and in 

 this way I obtained traces in which the number of vibrations corre- 

 sponds exactly to the height of the sharp sound perceived ])y the 

 ear. There can therefore be no doubt as to the thoracic origin of 

 this sound. 



Buzzing occurs only in the Hymenoptera and Diptera, because it 

 is only in these insects that the deformation of the thorax by the 

 action of the muscles of flight takes place over a surface sufficient!}^ 

 extensive to produce a perceptible sound. — CompUs Bendas, Oct. 7, 

 1878, p. 535. 



On the Ascarides of the Seals and Toothed Whales. 

 By Dr. H. Krabbe. 



Professor Leuckart's notice * of an Ascarid voided by a child in 

 Greenland, which he described Tinder the name o^ Ascaris 'maritima, 

 and supposed to have probably belonged to a seal or some other 



* Die menschlichen Parasiten, Bd. ii. 1876, p. 877. 



