ORTHOPTERA. 
56 
in such myriads on a clear still day are certainly peculiar, and it is at 
least probable that a number never come, in this form, within our ken, 
but remain at higher levels ; then too no one knows what insects are 
found in the air above the trees or how far this zone extends ; what do 
swallows get when they are hawking high up, far above the trees ? Ait- 
ken speaks of a butterfly (Melanitis ismene) soaring far above into the 
air and no one knows what countless forms of winged insects may not go 
to these levels as soon as they emerge. There must be a limit to this 
zone, but we would hesitate where to put it unless, for the plains, we give 
an outside limit of, say 3,000 feet. When the day of flying machines- 
dawns we shall certainly find insects of interesting kinds above the trees, 
and we should like to see ‘ 4 kite ’ ’ nets employed to investigate the 
fauna. 
It is perhaps not unprofitable to consider, in the light of the above 
remarks, how little of our insect world we probably know or attempt 
to know. In this country, progress beyond the stage of classifying and 
naming the insects most easily got has scarcely been made at all and this 
must come first; but it is certain that the only insects that have been 
found, named and placed in Museums are those which fly by day, or 
which live on bushes, etc., above ground, or which come to light. A 
great number of insects come to light, notably perhaps a part of the 
‘ 'surface soil fauna” and other retiring insects; but we do not know that 
there are not hordes which never come to light, which are never seen, 
and of which we are quite ignorant. This is true probably of all countries 
and the fauna of the soil, except as regards the large forms, is extremely 
little known even where naturalists andj collectors abound. (The same 
is to some extent true of freshwater.) How much more will this not be 
the case with the tropics, especially with the drier parts where much of 
the fauna is known to go to the soil. We know from experiment that 
many species go to the surface soil to spend the hot weather ; but there 
are no records that they were ever found there ; put out a light trap on a 
still moist evening during the monsoon and see the countless insects 
that come and the number of kinds; very many are never found in any 
other way, yet they and how many more, must be hidden somewhere. 
Blattid^e.— Cockroaches, 
Flattened insects, the large forewings lying flat on the abdomen, 
completely covering the hindwings. Coxce large and covering 
the lower surface of the thorax. The head 
turned down and hidden from above. 
Cockroaches have a very characteristic general appearance and are 
usually recognizable at sight; they include small fragile insects of a 
