1917] Colorado Species of Lachnus 135 



*Lachnus palmerae, n. sp. 



Stem Mother, First Instar. — General color ashy gray, due to a fine 

 white powder which covers the body; eyes, tips of antennae and beak, 

 and the cornicles, black or blackish; a dusky to blackish transverse 

 band, usually interrupted for some distance in the middle, upon the 

 first abdominal segments; upon either side of the prothorax, an oblique, 

 impressed dark line ; and extending over the abdomen, about six rows of 

 small impressed dark spots. A very narrow median dorsal dark line is 

 usually quite distinct and is due to the absence of the white powder. 

 Antcnna3, legs and body rather hairy; antennae with four joints, the 

 third being more than half of the antenna in length; fourth joint termi- 

 nated by a short conical spur. As the lice grow in this instar the white 

 powder increases in amount. At base of the spur is a single prominent 

 sensorium. Length about 1.35. 



The young lice, upon hatching, cluster on the bark of the twigs 

 to insert their beaks and feed. See figure IG. 



Described from specimens taken on a small Engelmann spruce 

 on the college campus, March 17, 1910. 



Adult Stem Mother. — The general color is a dark sordid brown, in 

 some examples almost black; all of the lice conspicuously marked with 

 gray or whitish lines and spots; a black transverse band, which is broken 

 at the middle, extends across the first segment of the abdomen to the 

 lateral margins; in front of this are black or dusky splashes upon the 

 segments of the thorax, making two broken black bands extending to 

 the head; the first and last joints of the antennae, the distal ends of joints 

 4 and 5, the eyes, all of the tarsi, the coxae, the knees, the distal ends 

 of the tibiae and their extreme bases, the cornicles and beak and the 

 genital plates, black or blackish. From the head to the tip of the 

 abdomen upon the dorsum is a narrow gray line on either side of which 

 are broken transverse gray lines about one to each segment, and all 

 about the same width as the median line, and in most instances, in 

 two pieces, on either side of the median line. The head is light rusty 

 brown, more or less covered with white powder; the antenna and the 

 greater portion of the femora and tibiae, are pale yellowish or sordid 

 white in color. The cornicles are large, broad at the base, moderately 

 elevated and mammiform in shape, and the beak reaches to the hind 

 margin of the third segment of the abdomen; legs, antennae and entire 

 body, rather thickly set with slender hairs; head small, quite convex in 

 front and usually distinctly bi-lobed; cauda not apparent. Length of 

 body, 3.75 to 4 (balsam spec. 3 to 3.50) by 2.40 wide; length of antenna 

 1.30; joints: III, .45; IV, .20; V, .23; VI, (with spur) .17, with little 

 variation. See figures 16a to 19. 



Apterous Viviparous Female. — In general appearance and markings 

 like the stem mother. No figures. 



*I take pleasure in dedicating this species to Miss Miriam A. Palmer, not 

 merely because she made the drawings for this and other aphid papers, but because 

 she takes a keen and intelligent interest in everything scientific, and especially 

 in the Aphides, and our friends, their enemies, the Coccinellidce. 



