BIOLOGICAL STUDIES OF APHIS RUMICIS, LINN. 



85 



tubercles present on each side. Cornicles dark to black, short, small, tubular, im- 

 bricated, a little longer than the cauda viewed from the dorsum. Cauda smaller than 

 in w.v. $ ; covered with short spines and several long hairs ; distal portion black. 

 Anal plate black. Genital plate black, bearing two dark claspers (gonapophyses) 

 clothed with spines and stout hairs. Penis sheath paler. 



6. Oviparous Female (fig. 5). Average size, 1-6 mm. bj^ 0-9 mm. 



Body small and narrow compared with the a. v. $, tapering posteriorly ; dirty 

 brownish black to dark green in colour, often of a dark green velvety appearance ; 

 short hairs distributed over the body. 



Head black to dark green. Eyes small, black ; accessory eyes small. Antennae 

 about two-thirds length of body ; pale dirty grey, segments 1 and 2 and distal portion 

 of 4 and 5 darker ; seg. 6 about equal in length to 3, 4 and 5 together ; 3 longer 

 than 4 or 5 ; 4 slightly shorter than 5 ; a compound sensorium on seg. 6 and a sub- 

 apical sensorium on 5 ; a few hairs over each segment. Rostrum normal, dark on 

 distal portion, with fewer hairs on the segments. 



Thorax with lateral tubercles on prothorax prominent. Legs relatively short and 

 stout ; of a dirty greyish colour, with coxae, trochanters and tarsi darker ; hairs on 

 all segments, especially on tibiae ; tibiae of third pair of legs much swollen, and 

 possessing numerous irregular roundish light-coloured areas (? sensoria) over the 

 whole length. 



rv. i-^f\> 





Fig. 5. Aphis rmnicis, oviparous 2 : (25) dorsal 

 view ; (26) antenna ; (27) rostrum ; (28) tibia of third leg ; 

 (29) Cauda, dorsal view ; (30) posterior end of venter, a.p., 

 anal plate, g.p., genital plate, c, cauda ; (31) cornicle. 



Abdomen dark green, with occasional lighter-coloured areas; two tubercles on 

 each side. Cornicles quite small, black, imbricated, tubular, a little longer than the 

 cauda as viewed from the dorsum. Cauda small but stout, black on distal portion. 

 Anal plate black. Genital plate bilobcd, black, and covered with long hairs. 



Ova, when first laid, somewhat greenish, but rapidly becoming black and shin}/ on 

 exposure to the air. Average size, 0-5 mm. 



(24:G— B) 



