HEMIPTERA. 201 



without alteration ; but serves to shelter the eggs which are to 

 give birth to her future offspring. These eggs, when matured, 

 pass under the body of the mother, and the latter by degrees 

 shrinks more and more till nothing is left but the dry outer convex 

 skin, and the insect perishes on the spot. Sometimes the insect's 

 body is not large enough to cover all her eggs, in which case she 

 beds them in a considerable quantity of the down that issues from 

 the under or hinder part of her body. There are several broods 

 of some species in the year ; of the bark-louse of the apple-tree 

 at least two are produced in one season. It is probable that the 

 insects of the second or last brood pair in the autumn, after which 

 the males die, but the females survive the winter, and lay their 

 eggs in the following spring. 



Young apple-trees, and the extremities of the limbs of older 

 trees are very much subject to the attacks of a small species of 

 bark-louse. The limbs and smooth parts of the trunks are some- 

 times completely covered with these insects, and present a very 

 singularly wrinkled and rough appearance from the bodies which 

 are crowded closely together. In the winter these insects are 

 torpid, and apparently dead. They measure about one tenth of 

 an inch in length, are of an oblong oval shape, gradually decreas- 

 ing to a point at one end, and are of a brownish color very near to 

 that of the bark of the tree. These insects resemble in shape one 

 which was described by Reaumur* in 1738, who found it on the 

 elm in France, and GeofFroy named the insect Coccus arhorum 

 linearis, while Gmelin called it conchiformis. This, or one much 

 like it, is very abundant upon apple-trees in England, as we learn 

 from Dr. Shawf and Mr. Kirby| ; and Mr. Rennie§ states that he 

 found it in great plenty on currant-bushes. It is highly probable 

 that we have received this insect from Europe, but it is some- 

 what doubtful whether our apple-tree bark-louse be identical with 

 the species found by Reaumur on the elm ; and the doubt seems 

 to be justified by the difference in the trees and in the habits of 

 the insects, our species being gregarious, and that of the elm 



* Memoires, Vol. IV. p. 69, Plate 5, figs. 5, 6, 7. 

 t General Zoology, Vol. VI., Part I. p. 196. 

 t Introduction to Entomology, Vol. I. p. 201. 

 § Insect Transformations, p. 92. 



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