THE PEA APHIS WITH BELATION TO FORAGE CEOPS. 



23 



Sexuparse. — What we have supposed to be wingless sexuparse, 

 that is, viviparous females which give birth to the sexual forms, 

 differ from the summer wingless viviparous females only by a larger 

 number of sensoria borne on antennal segment III. There is no 

 positive assurance that these are sexuparse but all of our mounted 

 specimens showing this character were collected in September or 

 later. Likewise, wingless viviparous females, collected in Russia dur- 

 ing September by Dr. A. Mordwilko and sent us by Dr. N. Cholod- 

 kovsky, bear a similar number of sensoria. Six antennse of speci- 

 mens collected at La Fayette, Ind., in October bear 10, 7, 8, 9, 13, 

 and 16 sensoria, respectively, on segment III, and eight antennse of 

 specimens collected in Russia in September bear 21, 22, 14, 7, 9, 9, 

 9, and 10 sensoria respectively, on segment III. 



Aberrant form. — In the fall it is riot uncommon to find a form 

 which has the hind tibia swollen and bearing numerous sensoria, a 

 character of the oviparous female, but instead of eggs the body often 

 contains living young. 



DESCRIPTIVE NOTES ON TYPE OF TRIFOLII PERG. 



The type slide of M. trifolii Perg. which we examined September 

 5, 1911, bears the following data on label: "7205 (Nectarophora) 

 Macrosiphum trifolii n. sp. Perg. on clover, Charlottesville, Va., Apr. 

 28, 1900." There are five winged viviparous females on the slide, 

 the bodies of which are shrunken. The second branch of the median 

 vein branches at a distance from the tip of the wing varying from 

 one-half or less to three-eighths the distance from the tip to where 

 it first branches, but usually the branching is nearer to the tip than 

 to the point where the media first branches. Cornicles imbricated 

 over their entire length but more distinctly near tip; the tip not 

 reticulated. From the balsam specimens the tips of the cornicles 

 appear to have been dusky in life, the remainder concolorous with 

 body. Measurements of the antennal segments, cornicles, and cauda 

 were taken as follows: 



Antennse. 



I. 



II. 



III. 



IV. 



V. 



VI 

 base. 



VI 

 filament. 



Mm. 



Mm. 



Mm. 



Mm. 



Mm. 



Mm. 



Mm. 



0.156 



0.069 



0.678 



0.556 



0.574 



0.243 



Broken 



.156 



.078 



.609 



.522 



.539 



Broken 



Broken 



.156 



.069 



.626 



.487 



.504 



.209 



0.749 



.148 



.069 



.591 



.487 



0) 



C 1 ) 



« 



.156 



.069 



.731 



.574 



.582- 



.226 



.801 



.156 



.069 



.757 



.609 



.609 



.226 





.174 



.078 



.835 



.661 



.661 



.243 



.836 



.156 



.069 



.870 



.661 



.661 



.261 



.905 



.156 



.069 



.661 



.556 



.591 



.209 



.731 



.156 



.069 



.661 



.556 



.582 



235 



.818 



• i Not measureable. 



