BIOLOGICAL STUDIES OF APHIS RUMICIS, LINN. 



83 



Head: Eyes black, with prominent accessory eyes. Antennae six-jointed ; seg. 1, 

 apical portion of seg. 5 and proximal portion of seg. 6 black, remainder of a paler 

 colour ; j^eg. 6 (including processus terminalis) the longest, about equal to 4 and 5 

 together ; 3 about three-fourths the length of 6, longer than 4 ; 4 slightly longer 

 than 5 ; 1 and 2 subequal in length ; a single subapical sensorium on seg. 5 ; a 

 compound sensorium on seg. 6 ; a few hairs on all segments. Rostrum normal, with 

 a few hairs on the segments. 



Thorax with a prominent prothoracic tubercle on each side. Legs black ; tibiae 

 and proximal portion of femora paler ; segments bearing stout hairs, especially the 

 tibiae. 



Abdomen with two lateral tubercles on each side and sometimes one or two small 

 indefinite tubercles. Cornicles black, tubular, imbricated, slightly tapering distally, 

 varying in length, but usually about one and one-third to one and one-half times the 

 length of the Cauda as viewed from dorsum. Cauda with distal half slightly spoon- 

 shaped, black, clothed with short stout bristles and several long curved hairs. Anal 

 and genital plates as in fundatrix. 



3. Winged Viviparous Fem.\le (fig. 3). Average size, 2-4 mm. by 1-3 mm. 



Body : Head and thorax black to brownish black ; the abdomen varying from 

 dirty brownish black to olive-green, usually with irregular darker pigmented areas on 

 the abdomen. Small hairs scattered over the bod v. 



Fig. 3. Aphis rumicis, winged viviparous '^ : (13) dorsal 



view; (14) antenna ; (15) cauda, dorsal view, a.j!?., anal plate, 



g.p., genital plate ; (16) tarsus of third leg, p, empodium 



or pad ; (17) cornicle. 



Head black. Eyes black, with prominent accessory eyes. Antennae dirty brown 

 to black, varying in length, about two-third length of body ; seg. 3 slightly longer 

 than 4 ; seg. 4 slightly longer than 5 ; 1 and 2 subequal ; subapical sensorium on 

 seg. 5, and a compound sensorium on seg. 6 ; a varying number of about 12-18 

 subcircular sensoria distributed over seg. 3 and none or 1-4 over seg. 4 ; segments 

 3 to 6 imbricated. Rostrum dark towards distal end ; normal. 



(2416) r2 



