1 94 PHYSIS (V, 1922) 



less, scattered over its entire length. Hairs as in apterous form. 

 Beak surpasses second coxae. \bdomen providcd with darkenedpi- 

 liferous tubercles as in apterous form. Górmeles, cauda and anal 

 and genital shield as in apterous form. 



Relative measurements : 



Length 3. i3 



Width 1. 30 



f. t. I II III IV V VI f. 



Antennae 0.12 0.20 o. 10 i.i5 0.86 0.80 0.20 1.10 



Cauda. o. 5o 



Cornicles 1 .o5 



I" 2 ud 3 rd 



ÍFemora... 1.20 i.5o 1.60 



Tibiae ... 2.00 2.1 5 2.90 



Tarsi..... 0.20 0.20 0.22 



Rostrum. 0.72 



Hab. Common in all the province of Buenos Aires on Sonchus and Ci- 

 chorium. 



Obs. It is the common species found on the « sow-thistle » (Sonchus 

 oljsraceus) all over the province. At times it becomes injurious to culli- 

 vated Achicoria. Its very metalic color at once separates it from lizeria- 

 num which is also found on the « sow-thistle ». 



Macrosiphum urticae (Schr.) (fig. 5) 

 Apterous virgogene. 



Color : Body greenish, often with darker longitudonal stripes 

 running over the dorsum. Eyes reddish brown. Antennae concolo- 

 rous with body with the distal segments dusky. Bostrum greenish 

 with distal segments dusky. Legs body color to vello wish with tarsi 

 and portions of tibiae contiguous and equal in length to them, 

 dusky. Cauda and cornicles greenish to yellowish green. 



Morphological characters : Body oval in shape somewhat elonga- 

 ted with transverse rows of rather fine hairs on dorsal and ventral 

 segments. Antennal segments smooth, with definite scabrous im- 

 brications on II, faint on the greater part of VI, more pronounced 

 V, VI and íilament. III with short hairs, less than half its greatest 

 diameter and with from 5 to 6 rather small sensoria situated in 

 more or less a straight row on thebasal half of its length. Bostrum 

 attains second coxae with its apex. Gornicles smooth cylindrical 



