AGRICULTURAL ZOOLOGY. 369 



sidered would be equal to any of the cultivated species of the silk-worm, should proper at- 

 tention be devoted to it. He had found the caterpillar principally on the ceanothus ; hence 

 he had applied to it this specific name. The Chinese produce their silk from the Gatumia 

 atlas, to which species this is doubtlessly superior. Dr. Behr presented drawings of the 

 worm in three different stages of its growth. 



On the Orange Insects. 



AT a recent meeting of the Boston Society of Natural History, the following paper on the 

 insect so destructive of late years to the orange-trees of Florida, compiled from the notes of 

 the late Dr. Burnett, was read by Dr. A. A. JzJould : 



Dr. Gould observed, that during the winter of 1853-4, the last which Dr. Burnett spent in 

 Florida, he undertook, among other researches, to investigate the structure and natural his- 

 tory of the orange insect. This is a minute insect of the Coccus tribe, which, within a few 

 years, has so invaded the orange-groves as almost totally to destroy them. The essay 

 commenced by him was left in a very imperfect state ; and it is conjectured that he had 

 prepared other materials, so as to illustrate his paper with delineations in detail, but which 

 are either in other hands or have been lost. 



For the execution of his purpose, Dr. Burnett visited a place called Mandarin, formerly 

 of considerable wealth, where, it is said, twenty vessels might at once be sometimes seen 

 loading, but now in ruins. In 1837-8, Mr. Robertson carried to that place from New York 

 two .small orange-trees, about two feet in height, bearing fruit about the size of an egg, 

 with the insect upon them. The first year it was not known what they were, but in three 

 years they had spread over the whole point. The annual yield at this time was about 

 1,600,000 oranges, worth about $10 a thousand. The orange-growers reported that the 

 orange insect would spread during July and August to the prickly ash. Dr. Burnett did 

 not observe this, but noticed the same insect on the lemon. 



The insect has eight segments, besides the triangular head-piece. The females are from 

 z'sth to z'ffth of an inch in length. They usually contain from eight to fifteen eggs, the 

 development of which continues all winter. The males are from g^th to B'ffth of an inch in 

 length, and are winged. The wings lie over each other horizontally on the back when at 

 rest. They are two only, but behind them are halteres, consisting of a single joint, with a 

 process curved like a shepherd's crook. The wings consist, as usual, of flattened cells. 

 The legs have the middle pair shortest; tarsus, one-jointed; abdomen, rounded, (eight- 

 jointed, ) with a teat-like process at the end, from which extends a long stile, composed of 

 two semi-canals. The mouth and oral apparatus is rudimentary,, though the antennae are 

 ten-jointed and highly developed. The internal organs of nutrition are deficient or rudi- 

 mentary in this respect, corresponding with the oral parts. The eyes are four, two on each 

 side; the eye proper is oval, situated laterally, and consisting of a solid body, TiWth of an 

 inch in diameter, perfectly structureless, imbedded in a dark-red pigment, and covered with 

 a thin cornea. The accessory eyes are anterior and lateral from the others, and of the same 

 structure. The young, when excluded, are not fully formed, but remain under the shield 

 of the mother until developed and able to crawl away ; but as she may move along during 

 oviposition, the embryos may be found behind or around her. The fact, that one side of a 

 leaf is frequently found covered with the scales of males almost exclusively, would seem to 

 favor the idea that they are produced as a distinct brood ; and another fact, also, that among 

 a hundred specimens, old and young, examined during the winter, almost all were females, 

 and only, by chance, was one male found to be near. 



On the Protection of the Plum-Tree. 



A CORRESPONDENT of the Country Gentleman, writing from Western Massachusetts, gives 

 the following details of his successful experience in cultivating the plum. He says: I 

 attribute my success mainly to an hereditary strain of Yankee principle, producing a strong 



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