APPENDIX . 



325 



have been made on this particular point; but from the notes and from the 

 preserved specimens, it is probable that the life of the individual stem- 

 mother is short, that she does not con- 

 tinue reproduction more than five days, 

 and that the progeny of a single indi- 

 vidual does not reach fifty. 



May 21, 25, and June 4, leaves con- 

 taining winged migrants surrounded by 

 their progeny were picked from trees 

 other than No. .33, and these were pre- 

 served. It was, unfortunately, assumed 

 that the descendants of these migrants 

 would be identical with those of the 

 wingless forms, because at the field ex- 

 amination they looked so: therefore, 

 they were not followed beyond the 

 fourth stage, and no specimens were 

 gathered from any tree other than No. 3.'J after June 4. Nor have I any 

 notes as to the number of young produced by this form. 



It may be added that of the descendants of the stem-mother fully three- 

 fourths become winged, practically all of which leave the tree on which 

 they hatched. On a large tree it is at least very likely that many would 

 reach only another portion of it; but in the case of a tree like the one under 

 observation, I doubt if any of those that start from ever return to it. 



Fig. l.S— Larva just hatched from winged 

 form (under side), and second stage of 

 same (upper side); lioncy tubes yet fur- 

 ther enlarged. 



Fig. 19— Third stage from 

 winged form ; enlarged. 



Fig. 20— Fourth stage from 

 winged form ; enlarged. 



The larva produced by the winged form — which is both parthenogenetic 

 and viviparous, exactly as is the corresponding wingless form — resembles 

 that hatched from the egg, save that the honey tubes are a little longer and 

 that there is a sensory pit at the tip of the third joint. The second stage 

 has the honey tubes stout, longer than a body segment, a little flared at tip. 

 The antennee are now five-jointed, and have a single sensory pit at the tip 

 of the fourth and no obvious pittings at the enlargement of the fifth joints. 



