412 



PSrCHE. 



[November — December 1890. 



of structure. All except the basal 

 small joints are distinctly imbricated, 

 and the sensory pits are very much 

 larger than in either of the preceding 

 species. In this species the structure 

 of the pits becomes more evident, but 

 will not be further referred to here, as 

 the Peach aphis affords a more satisfac- 

 tory subject. The 3rd joint in this 

 species has seven or eight rather irreg- 

 ularl}' placed pits, extending the full 

 length of the joint. Joint 4 is free 

 while 5 has a single large pit near the 

 tip. Joint 6 has the usual little aggre- 

 gation, one large pit, margined by sev- 

 eral small ones. 



In the Cherry aphis, Myz7is cerasi 

 Fabr., the pores or pits are still larger, 

 and the structure of the pits is still better 

 brought out. On the 3rd joint, which 

 with all subsequent ones is imbricated, 

 there is a series of eleven very large 

 pits in a single line : the fourth joint is 

 free of such pits : the 5th joint has a 

 single large pit near the tip, and the 

 sixth joint as usual has a small group, 

 consisting here of a very large oval pit 

 with four smaller ones grouped at one 

 side. 



■K^ -^a- 



Fig. 4. 



Fig. s. 



Most interesting of all, is the Peach 

 aphid. Aphis persicae-niger E. F. 

 Smith. In this species the poriforous 



