PARKER: NEW ENGLAND 8ARC0PHAGIDAE. 21 
The concealed portion is folded and loriiis a .slit-like pocket. Tlic ui ins 
or sides of the \' are two long, slenth-r, i)rocesses which extend back- 
ward, upward, and inward to heyond the hase of the i)enis. Their 
posterior extremities articulate witli sliort, rod-Hke phites that extend 
downward to meet the anterior, internal (upper) surface of the acces- 
sory plate. The apparent object of this arrangement is to control 
the position of these plates. The action is entirely independent of 
the movements of the penis, and is so planned that when the genital 
segments are in their normal position the accessory plates are pushed 
downward and upward to fill in the space left between the base of tlie 
forceps and the sides of the notuni, thus completely shielding the 
delicate structures within. 
Joining the posterior margin of the base of the genital sternum just 
within the arms are two paired plates which move on the former like 
the flaps of a hinge. They extend backward to points opposite the 
sides of the penis as it hangs straight downward. The posterior por- 
tions of these plates bear long hook-like processes that curve downward 
and forward ending in a blunt point. These are the anterior claspers 
(vorderen Haken, Bottcher) and are visible in figures 37, 38, and 40 
(PI. 6). The posterior bases of the hooks form the posterior margin 
of the plates which bear them. Just behind are the posterior claspers 
(PI. 0, figs. 37, 38, 40; hinteren Haken, Bottcher). Between the 
bases of these claspers lies a small fulcral plate (PI. 6, fig. 38, fup.) 
on which they act. The posterior pair are shorter than the anterior 
and usually hang straighter doA\Tiward, though often inclined some- 
what diagonally to the side. They are prominently hooked at their 
tips. At the base, each bears a short process which in figure 37 (PI. 6) 
is seen extending upward and inward applying itself to the anterior 
surface of the penis near its base. Actually it is attached to the 
penis by membrane and the movements of the latter and the claspers 
are coordinate. The chitinous structure seen in the same figure 
extending from just above the base of the penis to beneath the genital 
sternum must correspond to what Lownie called the apodeme in his 
Anatomy of the Blow-fly. The name is scarcely applicable, but 
serves for the purposes of this paper. The penis moves on the pos- 
terior end of this plate as the fulcrum, and its movements are at least 
partially coordinated with those of the claspers. These probably 
serve to hold it in place during copulation, possibly somewhat for 
purposes of orientation. This is readily seen in a properly prepared 
