100 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 
Yersin 199 gives 40 or 50 feet as the height. Kohl 2 "" says that in fine 
warm weather the locusts fly very high, from 20 to 30 fathoms (150 to- 
200 feet) ; but in cloudy weather they tiy much lower, scarcely a fathom 
high. These statements evidently apply only to short local flights, 
as these writers were fully aware of the fact that V. migrator ins, of 
which they are speaking, frequently passes over extensive mountain 
ranges, covered with forests, which would of necessity require a greater 
elevation than that given. Bowles 201 says that C. italicus, when start- 
ing on a flight in swarms, gradually rises to the height of 400 or 500 
feet. 
As the elevation given by these writers is so far below that at which 
swarms of C. spretm attain in a general movement, we presume no at- 
tempt was made to ascertain the greatest height reached. 
7. OTHER FACTS IN REFERENCE TO FLIGHT. 
As stated in our former report, flights in different directions at the 
same time and place are not of frequent occurrence, but have been oc- 
casionally observed in the case of C. spretm. These are always one above 
the other and in different air currents, sometimes in directly opposite 
directions, sometimes one column crossing the other obliquely. The in- 
stances mentioned in our first report are the only ones of which we have 
any knowledge. 
Whether a swarm ever, by ascending or descending into a different 
current of air, changes its course without alighting, is a question as yet 
undecided. From their well-known habit of usually coming down to the 
ground whenever met by an opposing current, we would suppose such 
a case very rarely if ever occurs. Professor Aughey noticed in one in- 
stance where two swarms were moving in opposite directions, that some 
from the upper column dropped into the lower, where, as a matter of 
course, they could no longer be distinguished from the others, but doubt- 
less were borne along by the current in the direction this column was 
moving. 
There are some other points relating to flight which might properly 
be mentioned here, but as they have some connection with meteorolog- 
ical conditions we will defer mentioning them until we have discussed 
the bearing of meteorological influences on the migrations of locusts. 
But this branch of the subject will be included in a separate chapter ^ 
hence all points inseparably connected therewith will be included in that 
chapter. We will therefore pass to the other divisions of our subject, 
referring to the chapter on meteorology as may be necessary as though 
it had been introduced at this point in our discussion. 
Supposed tendency of swarms approaching the sea to drive onward and 
fall into it. — In the preceding portion of this chapter relating to locust 
flights in other countries, the reader will observe frequent mention of 
i^Biblioth. Univ. de Geneva, 1858, 272. **Reise in Siidrussland, iii, 102. »' I. c 
