LIFE HISTORIES OF MUSCA AND ALLIES. 41 



sucking disks at the extremity of the proboscis are small and 

 inconspicuous as compared with those of the house fly." 



Plate IV., Figs. 4, Q, gives an idea of the differences 

 between this savage genus of biters and the more numer- 

 ous, but less rabid, Musca. In describing the wonderful 

 adaptability of the mouth parts, Packard (Guide, page 

 409) says : " In the proboscis of the house fly the liard 

 parts are obsolete, and instead we have a fleshy, tongue-like 

 organ (Plate IV., Fig. 5), bent up underneath the head 

 when at rest, the maxillae are minute, and the palpi (mp) 

 are single jointed, and the mandibles (m) comparatively 

 useless, small, and short compared with the lancet like jaws 

 of the mosquito or horse fly. The structure of the tongue 

 itself (labium, 1) is most curious. When the fly settles 

 upon a lump of sugar, or other sweet object, it unbends 

 its tongue, extends it, and the broad, knob like end divides 

 into two flat nuiscular leaves (1), which thus present a 

 sucker-like surface, wntli which the fly laps up liquid 

 sweets. * * * The inside of this broad, fleshy ex- 

 pansion is rough like a rasp, and, as Newport states, 'is 

 easily employed by the insect in scraping or tearing deli- 

 cate surfaces.'" 



The foregoing gra])liic description of this organ, the ac- 

 curacy of which we have carefully verified by minute ex- 

 amination, seems to demonstrate that the house fly is not 

 a biter. 



Alluding to its raison d'etre, a subject which fittingly 

 closes this chapter, the same author ^^^ (p^ige 479) writes: 

 "It should be remembered that flies have an infancy as 

 maggots, and the loathsome life they lead as scavengers 

 cleanses and purifies the August air, and lowers the death 

 rate of our cities and towns. Tints the vounu; of the 



