THE BIOLOGY OF THE CHRYSOPIDAE 1309 
Very often the setae, for some reason, catch and hold debris of 
this nature. Perhaps these setae are more or less viscid. The large 
cell at the base of each seta has been described as glandular by Lurie 
(1898), who says furthermore that the setae possess a lumen to the tip. 
These long setae occur on all larvae, even on species not normally carry- 
ing a packet. The dorsal setae are the chief shifting agency. If the 
abdomen be horizontal and a bit of debris be on the seta, when the 
abdomen is bowed downward in this region the posterior setae are 
brought to the packet and will very likely catch into the packet, so that 
when the abdomen is straightened out the debris will be carried back 
with the posterior setae. This process takes place in a kind of wavelike 
shifting, and the packet is actually carried back as far as there are 
dorsal setae. ; 
After the larva has its packet restored, it remains quiet on a leaf or 
a twig. 
On tearing a packet apart, one finds that it is constructed from 
bits of debris or small particles of plant tissue which the larva ean 
readily find in its habitat. Insect skins, bits of spiders’ webs, egg sacs, 
the bodies of spiders and mites, bits of wood and bark, lichens, coccid 
seales and bodies, and insect parts—espetially legs, heads, wings (partic- 
ularly elytra), and antennae—constituted the usual materials of the 
packets seen. This mass is held together, it appears, by plant fibers, by the 
silky or cottony secretions of aphids, and by the silk of spiders. The 
writer found a large amount of such cottony materials accessible to the 
larvae. Lurie (1898) stated that the packets are bound together by 
silk spun by the larva. The packets of a few larvae were removed and 
then returned to the larvae in small pieces. Hach larva placed a part of 
the debris on its back, and gathered up the loose ends and thrust them 
into the part on its back but did not spin any silk to hold the mass 
together. The packet is characteristic of all instars, as is true of the 
Australian species; while silk spinning, in all the larvae observed, is 
confined to the last part of the third instar. 
There are, in literature, statements to the effect that most, if not 
all, chrysopid larvae put the skins of their victims on their backs as a 
measure of concealment. The trash carriers are the only ones seen that 
have this as a well-defined habit. Larvae of Chrysopa quadripunctata 
often carry considerable debris and may appear at times to have this 
habit, but there is never a well-defined packet present. Larvae of the 
oculata group have frequently been seen with a few aphid skins, or even 
a number of them, adhering to the setae (Plate LXXXVI, 3). This is to 
be regarded as accidental, however, or at least as incidental to the larvae’s 
living where there were aphid skins or cottony material, taken with the 
