638 A CHAPTER ON FLIES. 
abroad. Another bristle mould is found on rotting grass; 
the Hurotium herbariorum, pesters our botanists by its pres- 
ence in their collections of dried plants, and so wide is the 
geographical range of many kinds of smaller fungi, that no 
country and scarcely any latitude escapes their visitations. 
The exquisite elegance of the spores of the fungi should 
suggest the dry and wet mounting of them in glass slides for 
the microscope. Entire plants and portions of others could 
be readily prepared, and the patience, enthusiasm, and skill 
of a Bicknell are all that are requisite for a beginning in this 
direction. i 
It is with extreme reluctance that we lay down this fasci- 
nating little treatise ; its pages indeed may be read and re- 
read with constant profit. To this and to similar works, 
the botanist, the general enquirer, and the agriculturist are 
equally indebted, and well will it be for this country when 
the American press shall issue many and such as this. 

A CHAPTER ON FLIES. 
BY A. S. PACKARD, JR. 

[Concluded from page 596.] i 
THE common House-fly, Musca domestica Linn., scarcely 
needs an introduction to any one of our readers, and its 
countenance is so well known to all that we need not present 
a portrait here. But a study of the proboscis of the fly 
reveals a wonderful adaptability of the mouth-parts of this 
insect to their uses. We have already noticed the most per- 
fect condition of these parts as seen in the horse-fly. In the 
proboscis of the house-fly the hard parts are obsolete, and 
instead we have a fleshy tongue-like organ (Fig. 1), bent uP 
underneath the head when at rest. The maxille are minute, 
and their palpi (mp) are single-jointed, and the mandibles 
