Report (Volume 49, PT. 1) (Paperback)

Book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1897. Not illustrated. Excerpt: ... Remedies. The injury inflicted by this minute insect when occurring in such myriads can be prevented, if, at its first detection, the plants be thoroughly sprayed with fresh pyrethrum in water, in the proportion of one ounce to two gallons of water. See Insect Life vii, p. 392. A spraying with kerosene emulsion would also be effective. Some Characters of the Thripidse. The Thripida, when full study shall be given them, will doubtless be found to embrace numerous species. Those known to us as occurring in the United States have been referred to ten genera, such as Thrifs, Phlaothrips, Limothrips, etc.-- the names of all terminating in thrips. Their structure places them quite low in the class of insects. They have been included by some authors (as Packard) in the order of Hemiptera. They have also affinities with the Orthoptera and Neuroptera. They may not properly be assigned to any of the old seven orders, and there is therefore a disposition to set them apart in a distinct order, with the name Thysanoptera (meaning fringe-wings). Physopoda drawn from the bladderlike termination of their feet, has also been proposed for them. They are small, elongate creatures, measuring less than one-tenth (some less than one-twentieth) of an inch in length, with narrow, long-fringed wings lying flat on their backs in repose. They can run rapidly, often turning up the tip of their abdomen after the manner of the rove-beetles, or they leap or take wing when alarmed. The common ox-eye daisy, or a head of red clover, plucked at almost any time, will give examples of these interesting forms. A few years ago the Thripida were thought to be harmless insects, nearly all of them possessing carnivorous habits, and living mainly on other insects. More careful study has shown that many are h...