3$2 
Psyche 
[September 
In photographing spinning behavior, a movie camera was focussed 
in the plane of the saranwrap under which the larvae moved, and 
in analysing the films, I assumed that the movie frames with the 
larva’s head in focus represented moments when the larva, was 
making an attachment, while those with it out of focus represented 
moments when the head was lifted away from the surface and 
moving toward the next attachment site. This assumption is sup- 
ported by the fact that attachments of lines laid on glass slides occur 
in the same areas as the presumed attachments in the movies. 
As illustrated in Fig. 6a, attachments were not restricted to 
certain areas, but were spread along the sides and in front of the 
larva. Their distribution was not uniform however: they nearly 
always occurred near the edges of the spinning area, and were less 
common in the central portion of the area than in the anterior and 
posterior portions. The attachments in the central portion were 
usually made in the later part of a sequence of swings. 
There were discernible patterns in the sequences of attachments, 
but there were also many variations on these patterns. The most 
common patterns, illustrated in Fig. 6b, included movements from 
the anterior to the contralateral posterior zone (e.g. RF to LS), 
and the posterior zones to both ipsi- and contralateral anterior 
zones (e.g. LS to LF, LS to RF). Larvae often made series of 
attachments to alternate sides, but also made series of attachments 
on the same side. The functional significance of these patterns is 
not known. 
The result of the variety of sequences of attachments and the dis- 
persion of attachment points was that a larva laid lines running 
in many different directions each time it executed a series of swings. 
Another result was that there were usually no large holes in the 
array of newly laid threads. The variation in site and sequence of 
attachments may serve to eliminate holes in the sheet, and thus to 
prevent loss of spores through these holes. 
The variation in movements and the dispersion of attachments 
may be the product of regular patterns of spinning behavior, but 
such patterns were not noticed in this short study. 
References 
Brocher, F. 
1931. Observations biologiques sur la larve du Dclopsis aterrima Zett. 
et sur celle du Lcptomorphus walkerl Curt. (Dipteres myceto- 
philes). Rev. suisse Zool. 3 8(4): 67-76. 
