96 APHID NOTES 



Measurements: Length of body, 1.21 mm.; width, 1.154 mm. Length of 

 antennal segments: III, 0.44 mm.; IV, 0.33 mm.; V, 0.27 mm.; VI, 0.135 mm.; 

 spur, 0.49 mm. Length of nectaries, 0.15 mm.; length of cauda, 0.11 mm. 



Macrosiphum artemesicola Williams i" (Plate VIII, figs. 11 to 15.) 



On Artemesia vulgaris at Corvallis, Oregon, July 2, 1911. 



General color pale green and appearing as if covered with minute particles 

 of fine white powder. This appearance is in reality due to numerous capitate 

 hairs which cover the entire body but are not found on the appendages. This 

 species is a very active one and may be found in company with M. ludovi- 

 cianae on the above host on the stems and leaves, mostly on the former. 



Apterous viviparous female: General color light gi-een and almost identical 

 with that of the food plant. Antennae black except the first and second and 

 basal parts of the thu-d segments. Legs dusky to black except the basal part 

 of the tibiae and femora. Nectaries black. Cauda dusky. Antennae long 

 and slender and reaching beyond the nectaries and cauda. Each antennal 

 tubercle with a single capitate hair at its apex. First antennal segment 

 strongly gibbous on the inner side. Thu-d segment with two visible sensoria 

 near the base, fifth with one near the distal end and sixth with the usual number 

 at the base of the spur. The entire body is thickly set with toadstool-like 

 setae of which there appears to be two forms. They are in reality about the 

 same size and shape except that those on the head and at the base of the cauda 

 have a longer stem than those on the rest of the body. The antennae are very 

 sparsely set with fine short hairs. The same is true of the femora and while 

 there are a greater number on the tibiae they are not as numerous as in the 

 previous species. The hairs on the cauda and caudal plate are rather sparse 

 and are longer than those on the legs and antennae. Nectaries slender and 

 slightly tapering. Cauda ensiform and rounded at the tip. The outer sur- 

 face of the latter seems to be made up of fine short pointed scales. 



Measurements: Length of body, 1.73 mm.; width, 0.88 mm. Length of 

 antennal segments: III, 0.58 mm.; IV, 0.49 mm.; V, 0.49 mm.; VI, 0.11 mm.; 

 spur, 0.75 mm. Length of nectaries, 0.44 mm.; length of cauda, 0.154 mm. 



Alate viviparous female: General color of head and thorax dusky brown or 

 black; abdomen similar in appearance to that of apterous form. Antennae 

 black at the tip shading to light green at the base. Legs dusky green at distal 

 end of tibiae and femora, lighter at base; tarsi black. Nectaries and cauda 

 dusky to black. Antennae longer than the body. Antennal tubercles strong 

 and each with three capitate hairs, center of forehead with two. Fu'st antennal 

 segment strongly gibbous and without hairs or bristles. Third segment with 

 about 14 round sensoria on the outer side of the segment, fourth apparently 

 with none, the fifth with one and the sixth normal. Wings hyaline but with 

 dark veins. Nectaries more slender than in the apterous form and thicker at 

 the base and tip than in the middle. Cauda tapering and with a broadly 

 rounded tip. 



^^ "The Aphididae of Nebraska," University of Nebraska Studies, X, no. 2, 

 p. 73. 



