214 PROTECTION OF WOODLANDS. 



1. ON CONIFERS. 

 Plant-lice (Aphidte). 



The Green Spi*uce Aphis, Spruce-gall Aphis, or Spruce Chermes, 

 Chermes viridis. This minute tree-louse, only 0*08 inches in 

 length, and of a yellowish-green to light brown colour, with 

 whitish down and white wings, bores into the buds of young 10 

 to 20 year-old Spruce for the purpose of depositing its ova to the 

 number of about 20 to 30 on the edges of the bracts or scales. By 

 means of the puncture thus made, and the absorption of the sap 

 by the young caterpillars, a cone-like swelling of the compressed 

 needles takes place, which assumes a green appearance at first, 

 but afterwards turns ruddy brown, and after it has opened at the 

 edges of the scales or leaf-bracts, so as to permit the exit of the 

 imagines in July and August, finally becomes dry and dull brown. 

 Fortunately the side-shoots are much more frequently attacked 

 than leading-shoots, for the shoots punctured assume curious 

 shapes and bends, and if badly attacked the young plants fall 

 into a sickly and unhealthy condition. The best remedial 

 measure consists in cutting off the galls, and drying and burning 

 them, whenever the insect becomes a pest. 1 



The Red Spruce Aphis, Chermes coccineus, which is somewli.it 

 smaller than the above species, and of a brownish-red colour with 

 white downy spot behind, has a similar life-history, but its met 

 morphosis takes place somewhat more quickly, so that 3 to 4 gei 

 rations usually take place in one year (Hess). The cone-j 

 occasioned by this louse are much smaller than the former, am 

 are usually located at the tip of the twigs without any shoots 

 above them ; at first of a green colour, they afterwards become 

 red, and finally brown. 



The Larch Aphis, Chermes laricis, a small blackish-bro^ 

 louse, easily recognisable from its white woolly pad, damages 

 needles of Larch from April till August, by sucking out the 



1 The remarkable manner of reproduction of this insect deserves some not 

 When the imagines swarm in July and August, the female, after impregnation, deposits 

 her ova on the needles and twigs, the ova being placed on long stalks and dusted over 

 with powdery wool. The brood issuing from these ova in a few weeks, first hiber- 

 nates, and then in the following spring deposits the ordinary eggs from which the lice 

 are developed. The insects appearing in autumn are merely females whose sole duty 

 is to deposit ova in the following spring. That is, the male and female insects pro- 

 duce, in the first instance, female eggs only, from which insects appear that, without 

 further impregnation, produce both male and female ova. Trans. 



