1917 



Colorado Species of Lachnus 



137 



Oviparous Female. — Differs from the stem 9 in general appearance 

 in being more slender in form, having the white markings much heavier, 

 and especially in having the head and all the abdomen back of the 

 cornicles, except the anal plate, white. The hind tibiae are thickly set 

 with sensoria throughout their length. Length of body 4 ; antenna, 1.15; 

 ratio of joints beyond the second — 30 : 14 : 16 : 13 (wth spur). See 

 figures 24 to 27. 



The eggs are yellowish brown when laid and measure 1.30 milli- 

 meters in length. They soon turn black in the daylight and are 

 deposited mostly on the bark of the twigs at the bases of the needles, but 

 sometimes are placed upon the needles also. See figures 24 to 28. 



Alate Male. — The males resembles the alate viviparous 9 , but are 

 much smaller, about 2.30 long, and more slender; the white markings 

 are lighter and the black markings upon the antennal segments are 

 absent, or nearly so. Joints 3, 4 and 5 of the antenna have many 

 tuberculate sensoria irregularly distributed throughout their lengths; 

 about 50 may be counted on joint III, about 15 on IV, and about 6 on 

 V. Ratio of joints beyond second about as follows: 20 : 10 : 12 : 7 (with 

 spur) . 



Described from examples taken on blue spruce, Ft. Collins, 

 Colo., October 14, 1910, by L. C. Bragg, and from Picea 

 Engelmanni, Fort Collins, 10-6, '09, by O. G. Babcock. See 

 figures 29 and 30. 



This is a very common species on the blue spruce in the 

 vicinity of Fort Collins, Colorado, and is altogether a bark 

 feeder attacking the small limbs. 



Our Collection records are as follows: 



