





52 THE INSECT WORLD. 
M. Guérin-Méneville is of opinion that these larve, which 
exist in great numbers in certain districts, sometimes devour 
all the nutritive substances contained in the ground. After 
having done so, they are obliged to come out of it, in order to 
seek at a distance a place where they will find food, or perhaps 
only a suitable place to undergo their metamorphosis. It is then 
that this singular journey commences. As regards the uniting of 
these myriads of individuals.into columns, M. Guérin-Méneville 
thinks that it can be explained by the necessity these insects feel 
for mutual protection against the drying effect of the atmosphere 
when they are forced to leave the ground. United into masses, 
and moistened by the glutinous matter which connects them, they 
can leave their former place of abode without danger ; if each 
were by itself, they would soon perish. Here, as in other cases, 
union is strength; and the strength of these larvee lies in this 
protecting moisture. However it may be explained, the migrations 
of these troops of insects are among the most astonishing pheno- 
mena of nature. 
BRACHYCERA. 
The Brachycera, from Ppayic, “short,” and xépac, ‘a horn,” 
those Diptera having short antenna, are divided into four groups. 
In this subdivision the sucker is composed of six bristles. Amongst 
other families it includes that of the Tabanide, the insects 
belonging to which family are of remarkable strength, and pos- 
sessed of daring and courage in the highest degree. ‘Their 
wings are provided with powerful muscles, their feet are very 
strong, and their trunk is provided with six flat, sharp lancets. 
Distributed over the entire world, their instinct is everywhere 
the same: it is the desire for blood, at least in the females, for 
the males are not so warlike. They do no harm, but live on the 
juices of flowers. They are chiefly found in woods and pastures, 
and, during the hottest part of the day in summer, may be seen 
flying about, seeking for their prey. 
M. de Saint-Fargeau has described the manner in which the 
males fly. They may be seen flying hither and thither in the glades 
of woods, remaining for some time suspended in the air, then dart- 
