l888.] NEW-YORK MICROSCOPICAL SOCIETY. 161 



ORGANS OF SENSE IN THE PALPUS OF PIERIS OLERACEA, HARRIS. 



Mr. L. Riederer read the following description of his exhibit: 

 " The labial palpi of Pieris oleracea, Harris, are three-jointed, 

 and bent upward, and are covered, especially on the forward 

 edge, with long, narrow, feather-like hairs. They are so long 

 that they overreach the head, and between them the maxillae are 

 rolled up when not in use. 



" In the distal end of the last joint, which is much smaller 

 than the other two joints, is an opening leading to a tube, which 

 finally widens into a chamber of the shape of a segment of a 

 sphere. The inside of the tube is covered with short hairs, or 

 bristles, all pointing towards the opening as if to bar intruders 

 from entering. The chamber shows a surface of disks, each one 

 of which bears in the middle of a depression an articulated, fine 

 hair. Below the surface, corresponding to each one of these 

 disks, are ganglion cells with nucleus and nucleolus. From this 

 layer of ganglion-cells a nerve-connection runs down the palpus, 

 " In comparing the structure of this organ with corresponding 

 organs of other insects, and organs of higher animals, there ap- 

 pears a striking similarity to the organ of smell. But it cannot 

 be overlooked that the organ of smell is, in animals generally, ex- 

 posed where, most likely, large volumes of air are to pass, while 

 here such opportunity is not apparent. Muscles may distend 

 and contract the cavity, and perhaps may augment in this way 

 the changing of air. 



^^ Pieris rapes, Schrank, shows similar arrangements. 

 "Dimensions were observed as follows : 



Palpus: ist joint, length, 1.3 mm.; width, 0.4 mm. 

 2d " " 1.3 mm.; " 0.4 mm. 



3d " " 0.37 mm.; " o.i mm. 



Cavity : full depth, 0.16 mm. 



Chamber : width, 0.05 mm. 



Disk: diameter, 0.009-0.012 mm. , 



Sense-hairs : length, 0.024 mm. 



" " diameter, 0.0018 mm." 



• SECTIONS OF HAIR OF THE HORSE. 



The Rev. J. L. Zabriskie : " The sections are from hair of the 

 tail of the Horse, jet-black in color, and of very dense, solid 



