HINDGUT CHANGES PRECEDING PUPATION 
AND RELATED COCOON STRUCTURE IN 
CHRYSOPERLA COMANCHE BANKS 
(NEUROPTERA, CHRYSOPIDAE). 
By Craig LaMunyon* 
Department of Biology, California State University 
Fullerton, CA 92635 
Introduction 
A blockage occurs between the midgut and hindgut of larval 
neuropterans in the suborder Planipennia (New 1986). Thus, the 
feces are stored in the midgut during larval life, enabling the hindgut 
to perform other functions. A compound stored in the hindgut of 
some larval chrysopid species is extruded from the abdominal tip 
and used as an adhesive during locomotion (Spiegler 1962) and for 
defense when the larvae are attacked (LaMunyon and Adams 1987). 
This adhesive/ defensive substance is produced by the malpighian 
tubules of chrysopid larvae. However, as pupation nears, the mal- 
pighian tubules produce silk precursors (Spiegler 1962), and 
undergo a dramatic histological change in the ca. 2 day transforma- 
tion from mature larva to prepupa (the cocoon building stage) 
(McDunnough 1909, Spiegler 1962, Wigglesworth 1972). The silk 
precursors flow from the tubules into the hindgut and are extruded 
from the anus during cocoon construction. 
The composition of chrysopid cocoons is not known. Larval silk 
does not have the solubility properties of protein (Lucas and Rudall 
1968), and Rudall and Kenchington (1971) suggested it might be “a 
kind of nylon with condensation of dicarboxylic and diamino hydro- 
carbons.” These authors also found that cocoons are composed of 
an outer fibrous silk, and an inner wall consisting of compact layers. 
Infrared spectroscopy suggested that the inner wall is composed of a 
polymerized molecule containing some alpha helical domains. They 
placed the cocoons in the category of the cuticulin silks, which are 
produced by epithelial cells. 
♦Present address: Section of Neurobiology and Behavior, Cornell University, Ithaca, 
NY 14853-2702 
Manuscript received by the editor September 9, 1988. 
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