PSYCHE 



VOL. XXV APRIL. 1918 No. 2 



KEY AND DESCRIPTIONS FOR THE SEPARATION AND 

 DETER]\IINATION OF THE FIRST INSTAR STEM 

 :\IOTHERS OF THE THREE SPECIES OF APHIDS 

 :\IOST COMINIONLY ATTACKING THE CULTIVATED 

 APPLE. 



By M. T. Smulyan, 



U. S. Bureau of Entomology, Melrose Highlands, Mass. 



The following key and detailed descriptions were prepared in the 

 spring of 1916, in Blacksburg, Va., while the writer was connected 

 with the Virginia State Crop Pest Commission, and were to form 

 part of a more extended paper, but as the publication of the latter 

 has been delayed, these are submitted separately in the hope that 

 they will prove of aid to those not yet familiar with the young stem 

 mothers of the above three species of aphids. 



Key.^ 



Cornicles long (about | to ^ of length of insect) . Fig. 1, B. 



(Base of distal segment of antennfe distinctly shorter than the 

 flagellum or unguis or distinctly less than one-half the total 



length of the segment.) Fig. 1, A 1. Aphis 



malijolice Fitch {Aphis sorbi Kalt. of recent American authors). 

 Cornicles short or very short (longest about of the length of an ab- 

 dominal segment) . Figs. 2 and 3, B. 



Base of distal segment of antennse as long or nearly as long as the 

 unguis or equal or nearly equal to one-half the total length of 

 the segment; cornicles about as long as an abdominal seg- 

 ment. Fig. 2, A and B 2. Aphis povii DeG. 



Base of distal segment of antennse distinctly shorter than the 

 unguis or less than one-half the total length of the segment; 



cornicles tuberculiform. Fig. 3, A and B 3. Aphis pruni- 



folicp Fitch (Aphis avenoe Fab. of recent American authors). 



'The characters utilized here, as well as most of those embodied in the descriptions, can 

 be made out by means of an hand lens or binocular microscope. The figures were drawn 

 from balsam mounts. 



