408 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



NOTES OX RECENT liKSEAUCH. 



{See also j^age 1H().) 



The ArrLE Arms. 



Apple Aphis, The. Aj)}iis Mali, Koch {U.S.A. St. Bd. Oregon, 

 pp. 81G Ii82). — Dr. Jolni ]>. Smith lias an instructive article upon the 

 common Ap])le Aphis. 



After some remarks upon the method of study he deals ^\ith the 

 life-cycle. He found on -March 28 Apple huds covered with aphis ; and 

 usually the aj)pearance ia coincident with the o))ening of the leaf-huds. 

 After two or three days from the time of hatching the larva moults, 

 becoming larger in the body, while the honey-tube is considerably longer. 

 The second moult is reached three or four days after the first ; the larvie 

 are then about double the original size ; they have eyes consisting of 

 several small lenses, whereas in the first stage there were only a few large 

 ocelli, while young embryos are beginning to be visible through the cell- 

 wjill. The writer notes that the insects are continually sucking up cell-sap 

 in far greater quantities than they re(piire, the surplus being excreted 

 either through the honey-tubes at the end of the body or through the 

 anal oyiening, forming the well-known honeydew which gives a glazed 

 a]>))earance to the leaves. 



The fourth stage is reached a few days after the second moult. Here 

 the embryos have grown considerably within the body of the parent, and 

 many minor changes are evident, i)articularly in the antenna* and honey- 

 tubes. 



The fifth stage, which is reached about fifteen days after birth, is the 

 stage at which reproduction begins. The " stem-mothers," as they are 

 called, are '08 in. long, bright green, and almost pear-shajK'd. At this 

 stage there is no separation of sexes ; there are neither males nor females, 

 but every iiulividual is capable of ])roducing young. The young are born 

 alive and ready to feed at once. The " stem-mothers " hav(> live-jointed 

 antenna*, while the tips of certain of the leg-joints (the tibia and tarsi) 

 are blackish, the latter character never appearing in the larval forms. 



Soon after the birth of the first of this second series the aphides 

 began to wander mostly on to the leaves. The stem-mothers i)roduce 

 about eight or ten young ones per day. The young of these stem-mothers 

 dilier considerably from those hatched from the eggs, the legs being 

 longer and the beak as long as the body. The first moult is reached very 

 (piickly, the insects being then more oval and having five-jointed antenna*. 



In the third stage, which is reached about three days after the second, 

 a dilierence in the young is to be seen. After this second moult some of 

 the young are pear-shaped, while others are oblong, the latter having heads 

 and thorax larger, and distinct shoulders indicating wing pads, while the 

 former tend to become like the stem-mothers, and have embryos beginning 

 to develop. 



