NUMBER OF GENERATIONS ANNUALLY. 25 
the seeming desire on the pari of the pupae to secrete themselves \\ bile 
transforming to adults does not at all coincide with the idea of a 
supposed immunity from attacks of natural enemies. Surely our 
species of Blissus has not always lived where natural enemies were as 
few as they are with us at the present time. Even where we have 
both the long-winged and short-winged forms occurring together in 
timothy meadows there is no such haste exhibited on the part of the 
former to escape from the companionship of the latter, as observed 
by Professor Sajo. We know, however, that our specie- certainly 
does enjoy a considerable immunity from natural enemies, though its 
conspicuous colors in both the larva] and adult stages contrast very 
strongly with those of its usual food plants and its presence is still 
further advertised by its strangely persistent gregarious habits. We 
have come to suppose the species to be, in part at least, protected 
from attack by its vile odor, and so, indeed, it may be in the United 
States, but the writer fully believes that somewhere in its southern 
habitat it will be found to have one or more enemies, like the ant. 
Eciton Iki unit a in Fab., of Central America, for illustration. Our 
native ants, however, will seldom attack even the young. 
NUMBER OF GENERATIONS ANNUALLY. 
Over the most of its area of habitation in North America, at least, 
the chinch bug is two brooded, though in northeastern Ohio the 
writer has totally failed to detect the second brood, or, in fact, to 
perceive any indications that a second brood occurs; but this will be 
referred to later. As previously shown, there is not sufficient proof 
at hand to warrant the statement that there is, even in the far South. 
a partial third brood. It is probable that the number of broods of 
this species annually has been primarily decided in its home in the 
tropical regions by the wet and dry seasons occurring there, and that 
we have in the North these same broods occurring at slightly differ- 
ent periods under the influence of a change from wet and dry to hot 
and cold -easons. 
Belt, in his Naturalist in Nicaragua, has the following to say with 
regard to the seasons on the northeastern side of that country: " 'The 
rains set in in May and continue with occasional intermissions until 
the following January, when the dry season of a little more than three 
months begin-*' (p. 103). ''The heaviest rains fall in July and 
August, and at those times the brooks are greatly swollen." "In 
September, October, and November there are breaks of fine weather, 
sometimes lasting for a fortnight, but December is generally a very 
wet month, the rains extending far into January. SO that it is not 
until February thai the roads begin to dry up" (p. L04). It seems 
that possibly we have \\rw> the key to the secrel of the number of 
