ANATOMY AND PHYSIOLOGY 



35 



FIG. 42. 



Antennae of a moth, Samia cecropia. 

 male; B, female. 



be adapted for other than sensory functions. Thus the anten- 

 nae of the aquatic beetle Hydrophilus are used in connection 

 with respiration and those 

 of the male Meloe to hold 

 the female. 



Sexual Differences in An- 

 tennae. In moths of the 

 family Saturniidse (S. cecro- 

 pia, C. promethea, etc.) the 

 pectinate antennae of the male 

 are larger and more feathered 

 than those of the female, 

 and differ also in having more 

 segments (Fig. 42). Here 

 the antennae are chiefly olfac- 

 tory, and the reason for their 

 greater development in the 

 male appears from the fact 

 that the male seeks out the female by means of the sense of 

 smell and depends upon his antennae to perceive the odor ema- 

 nating from the opposite sex. 



The plumose antennae of the male mosquito (Fig. 43) are 

 highly developed organs of hearing, and are used to locate the 

 female; they have delicate fibrillae of various lengths, some of 

 which are thrown into sympathetic vibration by the note of 

 the female (p. 107). 



Meloe has just been mentioned. In Sminthurus mahngrenii 

 (Collembola) the antennae of the male are provided with 

 hooks and otherwise adapted to grasp those of the female at 

 copulation. 



Though systematists have recorded many instances of an- 

 tennal antigeny, the interpretation of these sexual differences 

 has received very little attention ; though a beginning in the 

 subject has been made by Schenk, whose results will be re- 

 ferred to in connection with the sense organs. 



Mouth Parts. On account of their great range of diffe- 



