24 
Journal of Agricultural Research 
Vol. XXVIII, No. 1 
legs and wings (PL 6, A) are longer than in the cryptocephalic period (PI. 5, F), 
and the thorax shows more structural details of the adult. The abdomen is 
still very large and completely fills the posterior two-thirds of the puparial 
capsule. 
The walls of the head have been derived from all the parts that were formerly 
invaginated in the embryo and larva, including the frontal sacs, the atrium, and the 
dorsal pouch of the latter. The eversion of the head pushes out the skeleton of 
the larval pharynx, and the entire lining of the pharynx and oesophagus comes 
out with it; but the larval linings of the tracheae and the intestine still remain 
within the body of the pupa. When the puparium is artifically removed, how¬ 
ever, the intestinal lining usually comes out attached to it, though the dorsal 
tracheal tubes ( tra) frequently break loose and remain only partly extracted. 
This small-headed phase of the pupa is but a transitory period and is rapidly 
passed over. In fact, the writer never found intervening phases between it and 
the next when the head has acquired its final external form and size (PI. 6, C,D). 
This arouses suspicion that the evagination of the head at this time may be in all 
cases a result of the handling of the specimen. Yet the fully formed head is so large 
in proportion to the size of the thorax that it does not seem as if it could have 
developed to this degree without a natural eversion at an earlier period of growth. 
* In the final phase of the phanerocephalic pupa 
(PI. 6, C, D) the head constitutes almost a third 
of the entire bulk of the insect. The abdomen has 
contracted much in size, but still shows the 8 seg¬ 
ments of the larva and, in addition, a small anal 
segment differentiated at the end. The thorax, 
wings, and legs have greatly increased and length¬ 
ened. The ptilinum (Pi) is now relatively small, 
but the bilobed, antennal ridge ( Ant ), the com¬ 
pound eyes ( E ), and the subocular lobes ( u ) are 
much larger. Each of these last consists of a thick 
basal part and a tapering terminal spur directed 
backward. Kunckel d'Herculais {27) noted similar 
subocular processes in the Syrphidae, which he says 
are peculiar to the pupal stage in this family, though in several tropical species of 
Terastiomyia and Elaphromyia they are present in the adult and developed into 
long appendages. One such species, T. lobifrons Bigot, is described and figured 
by Bigot ( 6) as having long, bent chitinous processes extending downward from 
the cheeks. Other forms are described by Saunders (48)* One of these, E. cervi- 
cornis Saunders (fig. 7), has long forked horns like the antlers-of a deer; another, 
E. alcicornis Saunders, has large platelike subocular appendages suggesting the 
horns of a moose. According to Dr. J. M. Aldrich those genera probably belong 
to the family Micropezidae. 
All pupae of the apple maggot were found to be in the final phase of the phanero¬ 
cephalic substage at the end of five days, though some mature earlier. Speci¬ 
mens killed at the end of three and four days were found in all of the last three 
phases of development, the cryptocephalic (PI. 5, F), the microcephalic (PL 6, A), 
and the macrocephalic (Pl. 6, C). Some of them transformed to flies within a 
few weeks, while others did not, but this variation is normal, and none was found 
to remain in a larval stage through the winter, as one writer has claimed. 
At some time between the first appearance of the larval head and the attain¬ 
ment of the final pupal form, the larval linings of the tracheae and usually the 
lining of the intestine are at last cast out of the body of the pupa. From now 
on the prepupal cuticle (Pl. 6, G, ppu) always shows the molted tracheal linings 
stuck flat against its inner surface. Those from the anterior spiracles ( ASp ) 
extend backward as two conspicuous tubes lying just below the level of the 
Fig. 7— Head of an adult fly with 
subocular horns, Elaphromyia 
cervicornis Saunders. (From Saun¬ 
ders, 43.) 
