MANNER OF BTRTH OF APHIDID^. 33 



tical to those already described, but in maii}^ such cases the young 

 aphis died before freeing itself from the sac. This Avas probably 

 due to the fact that the insect lay ui)on a niiscroscope slide instead of 

 being held aloof from the bark, as under normal conditions. 



How are other species of Aphidida^ born? In an attempt to 

 answer this question I have made observations on several species, 

 among which is the apple aphis (Aphis niali Fab.), which will be 

 considered at some leng-th. The birth of this species is similar in 

 all the stages to that of the woolly aphis, except in one or two minor 

 points. The legs, at least the last i)air, ai'c bent l):ick upon thcni- 

 ^elves, so as not to extend bcvt)nd the abdomen, while being jjressed 

 to the ventral surface by the pellicle. AVhcn {\\v young has all its 

 legs free from the sac the mother does not in all cases, as observed 

 with the Avoolly aphis, press her otfspring down for a footing, but 

 simply loosens her hold. Apparently the greater length of legs in 

 this species makes it unnecessary for the mother to assist her young 

 in this way. As soon as the young begin to free their antenna^ and 

 legs a delicate whitish substance appears on the tip of the abdomen, 

 as with the other species described. The so-called honey tubes of the 

 apple aphis, and kindred species, are bent toward the extremity of 

 tlie abdomen and held closely against the body of the insect by the 

 enveloping pellicle. As the edge of this membrane i)asses along over 

 these tubes they bow up, and when tlie ti})s are released they 

 straighten into nearly their normal position, liefore the final release 

 of the tubes the delicate transparent membrane, constituting the pel- 

 licle, can be readily seen stretched across the intervening space. 

 Owing to the relatively much shorter beak of the apple aphis than 

 that of the woolly aphis, I have not been able to see the waxy, thread- 

 like connection between the seta* and the cast pellicle. If present, th ■ 

 separation probably takes place when the last pair of legs is being lib- 

 erated, which Avould tend to prevent a view of the thread. AVhen the 

 legs of the apple aphis are free, the discarded pellicle adheres to the 

 tip of the abdomen for a short time, whereupon it is worked oft' by the 

 movements already described. In one instance, however, I distinctly 

 saw a young aphis deliberately remove the shriveled pellicle from the 

 lip of its abdomen with its hind legs. 



In all the other species of Aphididw which have been under con- 

 sideration the manner of birth, in every case, was similar to that of 

 those alreadv described. 



^Ir. Quaintance remarked that his observations as to the mode of 

 birth of aphides agreed with those of the speaker. lie called atten- 

 tion to the fact of i-ecent statements in literature to the eft'ect that 

 the so-called honeydew of aphides was excreted only from the anus, 

 7487— No. 07—07 3 



