AMERICAN DIPTERA. 335 



but in some forms < e. g. Apocephalus, Melaloncha) it is strongly 

 chitinized and adapted to piercing. 



The adult flies are very active and make but little use of their 

 wings, using them only to fly for short distances. When in motion> 

 they run about with a peculiar jerky, hopping motion which makes 

 them readily recognizable at a glance. They may often be captured 

 in sweepings from damp places, or running about on the ground 

 among decaying leaves or near carrion. Very often they may be 

 seen on windows. The numerous species which are parasitic on ants 

 are usually seen only in or about the nests of their hosts. 



The anatomy and transformations of the Phoridse have never been 

 described with any amount of detail. I give below the description 

 of a larva which is a species of Phora that was found by Hubbard 

 in the Mammoth Cave, Kentucky. 



The larva is cylindrical, narrowed in front, more suddenly narrowed behind. 

 Head small, rounded, convex, deeply inserted in the thorax ; above, on each 

 side, an acute, three-jointed tubercle; in front, a second pair of very minute 

 tubercles, separated byasutural line, which branches below them ; space between 

 the branches of the Y-shaped sutures excised, inclosing: the buccal opening, which 

 appears as a dark transverse slit. Three thoracic segments smaller than the 

 abdominal segments, retractile, bearing at or near the anterior border a row of 

 acute tubercles or spines; the prothoracic with a pair of tubular spines arising 

 from depressions at the middle of each side. Abdomen of nine segments, each 

 with three folds on the doi-sal surface, the posterior fold bearing a row of spines, 

 similar to those on the thorax; sides wrinkled, with tubercular prominences 

 between the segments, and one or two spines anterior to those of the dorsal row ; 

 ventral surface, each segment with three tranverse ridges, one median, slightly 

 in advance of the two lateral ridges; the last segments smaller, the terminal 

 with an anal projection consisting of two large retractile tubercles, directed 

 upward, and bearing spiracles, surrounded by six radiating spiny processes. 

 Color dull white, darker at the extremities. The pupa is visible through the 

 skin of the larva, which becomes an indurated puparium, light red in color, 

 oval, pointed at the ends, smooth and convex beneath, more depressed on the 

 dorsal surface, which is margined, with the segments indicated by ridges. The 

 extremities of the puparium show the parts of the larva unchanged. 



It appears from De Meijere's account (1901) that the larva of 

 Lonchoptera, although quite different in external form from that of 

 Phora, resembles it in many ways. Osten Sacken (1902) has also 

 recently given reasons for considering the Phoridse and Lonchop 

 teridse rather closer to the families included in his superfamily 

 Energopoda than to any other Diptera. He states specifically, 

 however, "A real affinity with Phora does not exist anywhere." De 

 Meijere thinks, from a study of the larva of Lonchoptera, that the 



TRANS. AM. KNT. SOC. XXIX. OCTOBER. 1903 



