STATES OF INSECTS. 183 



over the head. Under this head, too, may be noticed, 

 the glutinous secretion which clothes the grub of Cionus 

 Scrophularice, a little weevil ; and of Tenthredo Cerasi L. 

 a saw-fly, and that waxy or powdery substance which 

 transpires through the skin of the larvae of several Aphi- 

 des, Chermes, Cocci, Hylotoma ovata F., &c. The Aphis, 

 whose extensive ravages of our apple-trees (A. lanata) 

 were before described to you a , is covered and quite con- 

 cealed by this kind of substance, so that the crevices in 

 the bark which they inhabit look as if they were filled, 

 not with animals, but with cotton. The insect, also, 

 that forms those curious galls produced upon the spruce 

 fir, and which imitate its cones [Chermes Abietis L., Aphis 

 De Geer) secretes a similar substance. In these and 

 other cases of the same kind, this matter seems to be, if 

 I may so speak, wire-drawn through numerous pores in 

 certain oval plates in the skin, more depressed than the 

 rest of the back, arranged regularly upon the segments, 

 and exhibiting minute tuberosities. When young, these 

 animals have more of this secretion than when more ad- 

 vanced : it then hangs from their anal extremity in 

 locks b . 



But the insects most remarkable for a covering of this 

 nature are those Coccidce of which Bosc has made a ge- 

 nus under the name of Dorlhesia. De Geer is the first 

 author that notices them, and has given a. description 

 and figure of one species under the name of Coccus floc- 



3 See above, Vol. I. p. 29, 198—. 



b Tie Geer iii. 111. Comp. 121. It would be as well to adopt the 

 French word flocon, instead of locks or floeksj which strictly mean 

 very different things. 



