HOUSE FLIES AND BLUEBOTTLES 191 



bluebottles manifest in finding out where the meat-safe 

 is kept, and that, too, not merely should the meat be 

 actually becoming tainted, and therefore distinctly odori- 

 ferous, but even before with our blunter senses we can 

 detect any odour at all, except on close approximation, 

 it seems clear that the olfactory sense must be highly 

 developed. When again, bearing this in mind, we 

 notice the exceptional development and peculiar struc- 

 ture of the third joint of the antennae, and couple with 

 this such experiments as that referred to above, it seems 

 highly probable that the antennas, of whatever other 

 use they may be, at least serve the bluebottle in lieu 

 of a nose. The very position of the antennae, too, in 

 front of the face, gives the fly an advantage in following 

 the scent, and thus we may think of this hyaena of the 

 insect world pursuing its hunt for carrion, and, blood- 

 hound-like, following the trail by trusting to the 

 guidance of its antennal nose, searching for that which 

 is not merely to serve as temporary food for itself, 

 but also, and chiefly, as permanent subsistence for its 

 progeny. 



All the lower part of the face is red, and the two 

 bulging cheeks are thickly whiskered over with black 

 bristles. Below the hollow in which the antennae are 

 lodged is a wide groove, which receives the mouth- 

 organs when they are not in use. These are all in one 

 piece, the so-called "tongue" or "proboscis," which is 

 hinged to the head at the hinder part of the groove. 

 As it is gradually opened out, the two bright reddish 

 club-shaped maxillary palpi are seen guarding the 

 aperture. Plate II. shows a photograph of about two- 

 thirds of the "proboscis," taken from a microscopic 

 slide. This is all that is generally mounted, the basal 

 part being cut off because it does not so readily flatten 



