SOCIAL INSECTS 127 
In concluding this chapter it may be noted that the larve of 
many insects are found feeding together in ‘“ companies”, which 
have hatched out from batches of eggs laid at the same time 
and place. Probably the most remarkable case of associated 
larve is afforded by the maggots of certain of the little two- 
winged flies known as Fungus Gnats (Mycetophilide). One of 
these is familiar as the “Army Worm” (Sccava militaris) of 
Europe, and allied forms are native to the United States. The 
maggots live among rotting leaves, and are sometimes found 
moving from place to place, united together by sticky threads, 
and writhing along like a snake. The largest armies of this 
sort may include millions of individuals, and are stated to reach 
an extreme length of roo feet, with a breadth of 6 inches, and 
a depth of 1 inch. The migrations are probably dependent on 
the question of food-supply. 
