1986] 
Eberhard — Pupation in my cetophilid flies 
119 
the ventral surfaces of pupal abdominal segments (Eberhard 1970) 
probably represent cases in which the larval skin was only partially 
shed, and broke near the tip of the pupal abdomen. 
It has been argued that silk attachments to larval cuticle should be 
shed along with the larval cuticle (Eberhard 1970, Malloch 1917). 
Although this seems reasonable, it is clearly not the case in Lepto- 
morphus sp. How the larval skin is shed so smoothly without dis- 
turbing, as far as can be seen, the silk lines that form the only 
attachment of the animal hanging on its pupation line remains a 
mystery. 
Acknowledgements 
I am grateful to R. Gagne for kindly identifying specimens, and 
the Vicerrectoria de Investigation of the Universidad de Costa 
Rica for financial support. 
References 
Eberhard, W. G. 
1970. The natural history of the fungus gnats Leptomorphus bifasciatus (Say) 
and L. subcaeruleus (Coquillett) (Diptera: Mycetophilidae). Psyche 77: 
361-383. 
Malloch, J. R. 
1917. A preliminary classification of Diptera, exclusive of Pupiparia, based 
upon larval and pupal characters, with keys to imagines in certain fami- 
lies, Part I. Bull. 111. State Lab. Nat. Hist. 12(3): 161-407, pis. 28-57. 
