The Zoologist — December, 1808. 1JC7 



paves to the covering of some of the plant-lice and Chermes larvae. 

 He states that the material can be rubbed off the body, but is not very 

 easily so entirely removed that the surface of the skin is completely 

 exposed, some portion always appearing to remain attached to the 

 body ; further, according to this author, on the skin so exposed are 

 observed darker elliptical transverse spots tapering at both ends : these 

 spots indicate indentations out of which the white material is seen to 

 protrude, of which he also gives figures. He likewise observes that 

 the material in question is not monililorm, as Reaumur has stated 

 with regard to the secretion of plant-lice, but is composed of bundles 

 of remarkably fine short threads running across each other, and 

 without order or arrangement. Hartig observes at the end of his 

 quotation from De Geer that he has himself found woolly larvae on 

 the alder, but none in which he had been able to discover any deep- 

 lying glands. 1 have myself also looked for these depressions or 

 gland orifices, which are represented by De Geer as by no means 

 minute, at fig. 6 in his plate xxxv., but I have never been able to 

 discern them. I could see nothing at all resembling these black 

 transverse lines or depressions, but I observed the white substance 

 apparently issuing from various points of the skin, as if coming from 

 invisible pores. The substance itself, when placed on the stage of 

 the microscope and viewed with a power of 300, had the appearance 

 shown at fig. 4 ; that is to say, of very fine contorted white hairs, not 

 thicker than one of the dividing lines of my micrometer appeared 

 under the same power, thus proving themselves to be of extreme 

 fineness. 



I have no doubt that De Geer has described the same larva as 

 I have for that of Selandria ovata; but I am unable to clear up the 

 difference in our observations. On attaining its full growth the larva 

 takes to the earth and there spins a brownish black cocoon, to which 

 the adhering grains of earth give an appearance of roughness ; its two 

 extremities are of a less compact texture. The cocoon is double; 

 that is to say, there is an inner cocoon, which is shining and smooth 

 like silk, it is of a yellowish brown colour, and has a white transverse 

 band round the centre. This inner cocoon puts one in mind of those 

 of some of the ichneumons, which also have bands of another colour. 

 The outside case is represented at fig. 6 ; the inner cocoon at fig. 7. 



If the larva spins up in the summer the imago appears after the. 

 lapse of five weeks, but if in September the imago does not come 

 out until the following spring : it is singularly coloured, and it was no 



