SANBORN: KANSAS APHIDID.K, 



35 



bugs which had previously increased, and all were apparently 

 exterminated by the latter. Then the bugs soon disappeared, 

 presumably for want of food material. Soon the aphids ap- 

 peared aga,in as numerous as at first. Later the bugs reappeared 

 and the aphids disappeared. This alternation happened three 

 times during the summer. 



Among the honey-dew feeders was noticed a Tenthridenid, 

 which obtained the juice as the ant ordinarily does, that is, by 

 attracting the aphids' attention with its antenme. 



* 



Chaitophorus negundinus Thomas. Plate X, fig, 58. 



Head brownish and hirsute. Antenme dusky except at the 

 bases where they are paler, also very hirsute ; length of joints ;- 

 I, 0.09 mm. ; II, 0.072 mm. ; III, 0.43 mm. ; IV, 0.27 mm. j 

 V, 0.21 mm.; VI, 0.11 mm.; VII, 0.21 mm.; total lengthy 

 1.39 mm. Sensoria large, circular; five to ten on the third 

 segment, none on the fourth, one near distal end of the fifth; 

 about five or six small and one large one at the distal end of 

 the sixth. Eyes in young pinkish red and in the adult black. 

 Ocelli three in number and prominent; ocular tubercle promi- 

 nent. Beak, 0.03 mm. long, extending to second coxa; it is 

 dark at the tip, the remainder is pale yellow. 



Prothorax greenish and hirsute. Thoracic sclerites dark, in- 

 sertions light green. Wings hyaline, veins smoky black, dis- 

 coidals narrow. Stigma smoky, varying from a light to a dark 

 color; 0.16 mm. broad by 1.28 mm. long. Total wing expan- 

 sion, 7.24 mm. Legs hirsute, slightly dark at distal ends of 

 articulations. Stout and heavy in proportion to the body. 



Abdomen pale green. Honey-tubes darker than the abdo- 

 men, 0.09 mm. long, and broader at the bases than in the cen- 

 ter. Length of body, 2.35 mm. 



This form is gregarious on the box-elder (Xegimdo aceroides) . 

 Its colonies sometimes completely cover all the growing parts 

 of the tree. The tree, after being infested in this way, soon 

 becomes coated with a honey-like secretion which seals the. 

 breathing pores of the leaves and the aphid is forced to leave 

 for the want of food. After the aphid emigrates the tree puts 

 out new foliage and resumes its growth, if attacked early in the 

 season. This happened here in April, during which time the 

 viviparous winged forms were plentiful. 



