. The American entomologist. Entomology. 174 THE AMEEICAN ENTOMOLOGIST. infested by Chinch Bug than wheat put in upon land tliat has been ploughed. There is another fact which has been repeatedly noticed by prac- tical men. This insect cannot live and thrive and multiply in land that is sopping with Avater; and it generally commences its opera- tions in early spring upon those particular parts of every field where the soil is the loosest and the driest. There are, as is well known to Entomologists, many genera of the Half-winged Bugs, which in Europe occur in two distinct or " dimorphous
. The American entomologist. Entomology. 174 THE AMEEICAN ENTOMOLOGIST. infested by Chinch Bug than wheat put in upon land tliat has been ploughed. There is another fact which has been repeatedly noticed by prac- tical men. This insect cannot live and thrive and multiply in land that is sopping with Avater; and it generally commences its opera- tions in early spring upon those particular parts of every field where the soil is the loosest and the driest. There are, as is well known to Entomologists, many genera of the Half-winged Bugs, which in Europe occur in two distinct or " dimorphous " forms, with no intermediate grades between the two; namely, a short-winged or sometimes even a completely wingless type and a long- winged type. Frequently the two occur pro- miscuously together, and are found promis- cuously copulating so that tliey cannot possibly be distinct species. Sometimes the short- winged type occurs only in particular seasons and especially in very hot seasons. More rarely the short-winged type occurs in a differ- ent locality from the long-winged type, and usually in that case in a more northerly locality. We have a good illustration of this latter peculiarity in the case of the Chinch Bug, of which we received eleven specimens (Fig. 122) [Fig. 122.] some years ago from Can- ada "West, that unques- tionably are a dimorph- ous short-winged form of the normal long-winged form found so abundantly in the Western States. So far as we are advised, it has never occurred in such numbers in Canada as to do any damage there; neither is such an event probable, because, as al- ready stated, the Chinch Bug is decidedly a Southern species and does not flourish even in NewEngland and New York. Natural Checks to the Multiplication of the Chinch Bug. It will be asked why Chinch Bugs do not in- crease every season, with the same frightful rapidity and at the same terrific rate of Geomet- rical Progression, that has been referred to above. The answer is sim
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