PSYCHE 
VOL. XLI JUNE 1934 No. 2 
THE ORIGIN OF THE PERITROPHIC MEMBRANE 
IN SCIARA AND THE HONEY BEE 
By F. H. Butt 
Cornell University. 
Many explanations have been given for the origin of the 
peritrophic membrane. Some authors maintain that it is 
formed from secretions of the epithelial cells of the mid-in- 
testine and is non-chitinous in structure. Others think it 
is a continuation of the chitinous intima lining the oesopha- 
gus and is secreted by cells lying at the junction of the fore 
and mid-intestine. No investigation has been made of its 
origin in the embryo.* 
Recently while making an embryological study of Sciara 
I was interested in the extreme length attained by the sto- 
modseal membrane in the later stages. It so resembled the 
peritrophic membrane of the larva both in its position and 
in its point of attachment that a relationship between the 
two was immediately evident. Therefore a number of newly 
emerged larvse were killed and sections were made to see 
if a, peritrophic membrane were present in the very first 
stage, and if so, whether it had any resemblance to the 
stomodseal membrane in the embryo. The larvse were fixed 
in Carnoy-LeBrun fluid for thirty seconds and were em- 
bedded in rubber-paraffin. The sections were cut at four 
microns, were stained in magenta and counter-stained in 
picro-acid-carmine. 
*Since this paper was submitted for publication, a paper by Gam- 
brell has appeared (Ann. Ent. Soc. Am. Vol. XXVI : 641 ) mentioning 
the origin of the peritrophic membrane in Simulium. 
