The Larch Bug — What is it? 253 



generations, so much so indeed that one is apt to mistake the insect 

 as being oviparous and viviparous at different stages of life. They 

 are, in my opinion, ovi- viviparous — i. e., by a process of internal 

 gemmation the eggs are produced partially hatched, which somewhat 

 accounts for their extraordinary fecundity. With regard to the rela- 

 tion of sexes, I believe the insect to be a sexual, possessing the power 

 of multiplying for a given period without intercourse. A succession 

 of fruitful virgin aphides have been traced by Bonnet through nine, 

 and by Davan through eleven generations, and Kyber kept a colony 

 of them for four years without once seeing a perfect male insect. 

 Having said the tribe is continued by eggs deposited in autumn and 

 generating the following spring or summer, the question may be put, 

 "Will the severe frost of the north of Scotland not destroy the eggs ? 

 As to this, it has been tested over and over again that germs of 

 organisms will retain vitality under a much lower temperature than 

 living organisms themselves. I am, however, at a loss to know the 

 meaning of the generic name Adelgis as applied to this insect, and 

 feel inclined to call it a species of Coccincc, and grouping with the 

 Aphis in the sub-order Homoptcra. 



The insect being distinctly injurious to larch, a few words may be 

 here added suggesting a cure. A writer at page 105, in the last vol. 

 of " Scottish Arboricultural Society's Transactions," says plants can 

 be thoroughly cleansed by being, while in the sheugh previous to 

 planting, syringed with a solution of perchloride of mercury. Possibly 

 this may be so, but I doubt it much — although at the same time I 

 never tried it, because I fail to see how poison can affect the eggs so 

 as to destroy the germ. "What I would suggest is that the plants be 

 well syringed with a solution during July on one or more occasions, 

 to make sure of destroying the insect as it emerges from the egg. 

 The insect being suctorial, I am confident that any insect poison if 

 tiraeously applied will effectually extirpate this destructive pest. 



