109 



undertook, among other researches, to investigate the structure 

 and natural history 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 thsee 

 years they had spread over the whole point. The annual yield 

 at this time was about 1,500,000 oranges, worth about 810 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 ^-V to ^-V of an inch in length. They usu- 

 ally contain from 8 to 15 eggs, the development of which con- 

 tinues all winter. The males are from ^V to 7j\j- of an inch in 

 length, and are winged. The wings lie over each other horizon- 

 tally 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 style, composed of 

 two semi-canals. The mouth and oral apparatus is rudimentary, 

 though the antennse are ten-jointed and highly developed. The 

 internal organs of nutrition are deficient or rudimentary, 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, y-^o^ of an inch in diameter, perfectly 



