APPENDIX. 



321 



Fia:. 10 — Larva just born 

 from stem-mother; first 

 stage of seeond series ; 

 antenna and honey lube 

 further enlarged. 



They do not actually 



reached that stage. It is also well to remember 

 that I killed off everythiog- that hatched prior to 

 April 18 ; hence May 1 may be fairly assumed as 

 the date when the first " stem-mother " in the lati- 

 tude of New Brunswick is ready to propagate her 

 kind. These jjeriods are of importance because of 

 their bearing on the problem of reducing injury. 



The young that are born by the " stem-mother " 

 differ quite markedly from those hatched from the 

 eggs. The legs are longer, actually and in propor- 

 tion ; the honey tubes are as long or longer than a 

 body segment ; the antenna? are without any sense 

 pits, and the beak is as long as the insect itself. 



It is in place here to say that plant lice feed by 

 puncturing the plant tissue and sucking the juices, 

 eat any part of the leaf or twig ; hence arsenical poisons or any others that 

 act through the stomach are useless. The mouth parts consist of a jointed 

 beak in which there are four slender lancets, two of which are united for 

 the greater part of their course. These minute lancets pierce the plant 

 cells and absorb the sap ; the cells dry, and, as the sucking on the leaves is 

 done mostly from the under side, they curl and become deformed. Where 

 the infestation is on a fruit spur the supply of nourishment for the forming 

 apple is materially lessened, and often it drops. If it does not, full size is 

 not attained, and the honey dew, with its accompanying soot fungus, is 

 likely to cause deformation. 



Nay 4, reproduction was general, and young lice were present in large 

 numbers. The stem-mothers and their young now began to wander. 



The young did not at once fix near where they were 

 born ; many adults moved from twigs to the leaves, 

 which were now well developed, and they were 

 found even on the trunk and branches. Already 

 some of those born on the third had molted, the 

 first stage being, apparently, a very short one. 



In this second stage the beak is relatively shorter 

 and the insect is more oval. The honey tubes 

 exceed the body segments in length, and are thick 

 cylinders, tapering a little from the base. The 

 antenna? are now five-jointed, obscure sense pits 

 being located on the fourth and fifth. 

 May 5, colonies of stem-mothers and their young were found everywhere 

 on the leaves, usually from six to twelve young about a single mother, but in 

 a few cases over twenty on a single leaf, around a single female. Now, as 

 there had been no breeding before May 3, this means that from eight to ten 

 j'oung daily is about the capacity of these examples. Small wonder, then, 

 that in some cases where three or four stem-mothers had populated a leaf 

 this was already beginning to curl. 

 21 



Fig. II— 8ecoud stage of 

 second series; antenna 

 more enlarged. 



