22 



BULLETIN" 276;, U. S. DEPARTMENT OF AGRICULTURE. 



the remaining segments pale with a faint greenish tint and the tips 

 of III, IV, V, and all the base of VI dusky and filament of VI black. 

 Legs pale green, the tips of tibia and all of the tarsus blackish, basal 

 two-thirds to three-fourths noticeably swollen and bearing numerous 

 small circular sensoria (fig. 9b); cornicles as in other forms, just 

 reaching to tip of cauda, pale with slight greenish tint and the 

 tip dusky to blackish. Cauda pale green or yellowish. Measure- 





Fig. 9. — Macrosiphum pisi: Oviparous female, much enlarged; a, antenna, and ft, hind tibia, of same, 



more enlarged. (Original.) 



ments taken immediately after mounting: Length of body, 1.S2 ram. 

 (Another individual, apparently unfertilized, but with abdomen 

 abnormally distended with eggs, measured 2.21 mm. in length and 

 1.28 mm. in width.) Length of body to tip of cauda, 1.97 mm., 

 width, 0.93; cornicles, 0.46 mm.; cauda, 0.21 mm. Measurements 

 of antennal segments: 



I. 



II. 



III. 



IV. 



V. 



VI base. 



VI fila- 

 ment. 



Mm. 



Mm. 



.1/;;;. 



Mm. 



Mm. 



.1//;). 



Mm. 



0. 139 



I). (ITS 



(I. 1ST 



0.348 





2(H) 



O.iii.l 



.139 



.078 



.494 



.348 



. mi 



.209 



.643 



. [39 



.UTS 



.696 



. 435 



. 522 



.234 



.817 



. 156 



.009 



.748 



.135 



.522 



.252 



.800 



Egg. — The egg is pale to bluish green and shining when first laid, 

 gradually changing to jet black. It is elliptical oval, and measures 

 0.75 to 0.80 mm. in length and 0.35 to 0.40 mm. in width. 



