MOTIONS OF INSECTS. 341 
serene days covered so thickly by these webs, and what 
becomes of them? What occasions the spiders to mount 
into the air, and do the same species form both the ter- 
restrial and aérial gossamer ?—And what causes the webs 
at last to fall tothe earth? I fear I cannot to all these 
queries return a fully satisfactory answer; but I will do 
the best I can. At first one would conclude from ana- 
logy, that the object of the gossamer which early in the 
morning is spread over stubbles and fallows—-and some- 
times so thickly as to make them appear as if covered 
with a carpet, or rather overflown by a sea, of gauze, 
presenting, when studded with dew-drops, as I have often 
witnessed, a most enchanting spectacle—is to entrap the 
flies and other insects as they rise into the air from their 
nocturnal station of repose, to take their diurnal flights. 
But Dr. Strack’s observations render this very doubt- 
ful; for he kept many of the spiders that produce 
these webs in a large glass upon turf, where they spun 
as when at liberty, and he could never observe them at- 
tempt to catch or eat—even when entangled in their 
webs——the flies and gnats with which he supplied them ; 
though they greedily sucked water when sprinkled upon 
the turf, and remained lively for two months without 
other food*. As the single threads shot by other spi- 
ders are usually their bridges, this perhaps may be the ob- 
ject. of the webs in question: and thus the animals may be 
conveyed from furrow to furrow or straw to straw less 
circuitously, and with less labour, than if they had tra- 
velled over the ground. As these creatures seem so 
thirsty, may we not conjecture that the drops of dew, 
@ Neue Schriften der Naturforschenden Gessellschaft zu Halle 1810. 
v. Heft. 
