THE METAMORPHOSIS OF FLIES. 713 
12. For the purpose of observing and recording both the 
imbrication of the whorl and the relation of its parts to the 
axis, I make a diagram of the flower Fig. 125. 
(Fig. 125) and rule a table as on the oe 
opposite page (Table IT): ; 
In this diagram of the corolla of Py- p t 
rola elliptica (Fig. 125) p and p’ denote 
the upper or posterior petals ;7 and V the , 
lateral petal; and a, the anterior or lower T 
etal 
tal. 
In Table II the figures 1, 2, 3, 4, 5 se BERD A 
represent the successive parts of the NE 
spiral. The Table shows the summing ilies 
up of one hundred observations of the imbrication of the corolla 
of Pyrola elliptica Nutt. 
THE METAMORPHOSIS OF FLIES.* II. 
BY DR. AUGUST WEISSMANN. 
Ris AP 
Wuar appears most unusual in the development of the Muscidæ 
is the genesis of the thorax and head together with their append- 
ages. That this section of the fly’s body is completely formed 
anew, not standing in ‘genetic connection with the corresponding 
parts of the larva, contradicts the generally accepted and long 
prevalent view, according to which pupation is only a moulting 
process. As little does: this opinion agree with the fact of the 
total transformation which all the inner organs suffer during pu- 
pation. All the systems of the organs of the larva die, in part 
completely, in part cell by cell, in order afterwards to be built up 
anew. 
Evidently the metamorphosis of Corethra stands in diametrical 
Opposition to this mode of development, and indeed to the two 
previously described main points. Here the pupation may be 
tightly regarded as a moulting process; we see no phenomena ac- 
*Being the concluding chapter of “Die Metamorphose der 
ein weiterer Beitrag zur Entwicklungsgeschichte der Insecte: 
Weissmann. Mit. 5 Kupfertafeln. Leipzig, 1866. 8v0, pp. 83. 
Corethra plumicornis, — 
n. Von Dr. August 
y 
