SOME COLORADO SPECIES OF THE GENUS LACHNUS. 



By C. P. Gillette. 



Lachnus coloradensis, n. sp. 



Adult Stem Mother. — General color black, with more or less rufous 

 upon the head, thorax and legs; the anterior and nearly all of middle 

 femora, the proximal portion of hind femora, and the basal portions of 

 all tibiffi rusty brown, the hind tibiae being black nearly to the base; all 

 tibiae black at extreme base; antennse pale with distal ends of joints 

 3, 4 and 5 black. The black of the dorsum is mostly dull, but with 

 poHshed lines running across between each two segments, and a larger 

 polished area on joints 7 and 8. In some specimens there is somewhat 

 of a rufous tinge over most of the dorsum; cornicles black, mammiform, 

 terminating in a slightly projecting nipple; cauda scarcely apparent; 

 vertex prominent and convex. Length of body 4.25; antenna L90. 

 Joints of antenna: III, .50; IV, .26; V, .30; VI, .23; hind tibi«, 3.10; 

 beak attaining hind margin of third abdominal segment; sternum and 

 first two abdominal segments rusty brown; head small, convex in front; 

 one sensorium near distal ends of joints 3, 4 and 5, besides the permanent 

 one on joint 5, and sometimes there are two on joint 4. (See Plate X, 

 figures 1-3). 



The young of the second generation are pale gray with dusky green 

 upon dorsum of head and in the region of the cornicles, the thoracic 

 segments being nearly white, and the abdomen dusky to brownish. 

 (See figure 4.) 



Apterous Viviparous Female. — General color black or blackish, 

 somewhat shining, especially below; head, thorax, coxse and basal 

 portions of femora and tibiae more or less rufous; antennae pale with 

 distal ends of joints black; tentiinal joint all black; shape of abdomen 

 varying from broad oval to rather elongate. Length of antenna 2; 

 joints proportioned as follows: 7 : 6 : 43 : 22 : 25 : 14; sensoria as in stem 

 mother, except that there are usually two sensoria on joint 4; rostrum 

 nearly attaining tip of abdomen; cornicles mammiform, small, about 

 .40 across mammiform base; hind tibiae very long and curved. 



This form resembles the fundatrix so closely it was not thought 

 necessary to draw it. Antenna shown in figure 5. 



Winged Female of Second Generation. — Color rusty yellow to yel- 

 lowish brown; cornicles, genital plates, mesosternum, coxae, distal 

 half of beak, joint 6 and distal ends of joints 3, 4 and 5 of antenna, all 

 of the tarsi, distal ends and very short proximal ends of all tibiae (fully 

 four-fifths of hind tibiae), distal ends of all the femora, eyes and stigmas, 

 black or blackish. The distal ends of middle and front femora may be 

 only dusky; beak attaining 8th abdominal segment; dorsal surface 

 slightly pulverulent; upon the pronotum there is a diagonal lateral 

 line upon either side; there is a V-shaped white mark near the middle 

 of the anterior margin and one near the posterior margin of the meso- 

 thorax and a white line near insertion of either front wing. The 

 scutellum is more or less pov/dered, as is the metathorax, and transverse 

 white dashes and lateral spots upon 3rd and 4th abdominal segments. 

 See Plate X, figures 6 to 10. 



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