1970] 
Eberhard — Fungus Gnats 
377 
were darker and thus apparently older. More work is clearly needed 
to establish the details of this remarkable metamorphosis. 
It remains possible that the larval cuticle was shed during pupa- 
tion but was so thin that its movement was not observed ; indeed 
the swelling of the anterior segments prior to pupation suggests a 
rupture of the larval cuticle. A search for signs of larval cuticle 
on pupae did not yield clear evidence of its presence: pupal cuticle 
did have the same number and pattern of spiracles as the larva’s, 
but seemed to lack the rows of dark denticles near segmental 
boundaries on the ventral surface which were quite prominent in 
larval cuticle. 
Other mycetophilids are generally thought to shed their larval 
skin during pupation (Osten Sacken 1886), but masses of material 
occur near the posterior tips of the abdomens of the pupae of 
several species, including Ceroplatus sp. (Malloch 1917), Macro- 
cera anglica (Madwar 1935), Leptomorphus walkeri (Edwards 
1925, Madwar 1937), Speolepta leptogaster (Madwar 1937), 
Mycetophila cingulum (Madwar 1937), and My corny a limbata 
(Lindner 1949). Although in some cases (e.g. Macrocera anglica) 
this material apparently is the larval cuticle (Madwar 1935)) 
the details of the pupa’s position within its cocoon indicate 
that the material may not be larval cuticle in at least two of the 
other cases. Threads are attached to lateral projections along the 
sides of the pupa of Ceroplatus sp. (Malloch 1917) and My corny a 
limbata (Lindner 1949). As Malloch points out, any silken at- 
tachments the larva might make to itself would be shed with the 
larval cuticle, and it is difficult to imagine how the pupa could be 
suspended in such a way if the larval cuticle is shed. It thus seems 
possible that the larval skin is not shed in these species, and that 
the mass of material behind the pupa is a discarded portion of the 
larva’s body. 
The selective advantages of some aspects of Leptomorphus pupation 
are not clear. Ingestion of the head capsule and the possible failure 
to shed the larval skin may be involved in maintaining silk attach- 
ments to the pupa, and thus in suspending it on a thread. Suspending 
the pupa may in turn be advantageous at least in females because 
it makes the pupa more easily found by flying males. The contents 
of the discarded larval segments and the function of discarding 
them are not known. Active larvae defecated repeatedly, and their 
feces were a much lighter brown than the discarded body section, 
