46 BULLETIN 168, UNITED STATES NATIONAL MUSEUM 



stiff dorsal setae, and a long dorsal subapical seta extending to the 

 middle of the mucro. Mucrones (pi. 16, figs. 165-167) stout, 5- 

 toothed, bilamellate. A lamella on each side extends from the base 

 of the mucro to the anteapical tooth. Apical tooth relatively small, 

 almost straight or slightly hooked. Anteapical tooth large, sub- 

 conical, erect. Of the three remaining teeth, one is lateral and stout. 

 The two others are dorsal, equal, subcorneal, and usually almost oppo- 

 site each other; the anterior of the two being the more lateral. The 

 mucro bears a strong lateral seta extending almost to the apex of the 

 mucro. Rami of tenaculum (pi. 16, fig. 168) quadridentate ; corpus 

 with four ventral setae. General clothing of sparse short setae, with 

 longer stiff slender sensory setae, all the setae being simple. Integu- 

 ment smooth. Length, 1.7 mm. 



Cotypes—U.S.'tiM. no. 42980. 



Distribution — Recorded as follows: 



Washington: Nisqually Glacier, Mount Rainier, March 31, April 5, P. S. 

 Welch. 



PROISOTOMA (PROISOTOMA) SCHXFFERI (Krausbauer) 



Plate 16, Figures 169, 170; Plate 17, Figures 171-176 



Isotoma schafferi Krausbauer, 1898, p. 495. — Schaffer, 1900b, p. 260. — Carl, 

 1901, p. 258.— BoRNER, 1901a, p. 40. — Krausbauer, 1902, p. 70. 



Description. — "Light purple to brownish; often whitish at the 

 borders of the segments. Not infrequently the segments are mostly 

 whitish weakly pigmented with purple. Head wliitish with a little 

 purple pigment. Antennae purple. The living insect has a silvery 

 luster" (Krausbauer). "Gray-purple to greenish brown" (Schaffer). 



Specimens from Massachusetts are yellowish green or brownish 

 green, spotted with pale yellow; dorsmn blackish purple. Eyes con- 

 nected anteriorly by a broad purple mark; occiput with a median 

 purple spot. Eye spots large, black, approximate, close behind the 

 antennae. Eyes (pi. 16, fig. 169) eight on each side, subequal, or the 

 two anterior eyes larger than the others. Postantennal organ (pi. 16, 

 fig. 169) elliptical, small, in length shorter than, or equal to, the di- 

 ameter of an adjacent eye. Antennae about one and one-half times as 

 long as the head; segments cyhndrical, in relative lengths about as 

 18:26:23:27; first and second segments greenish with purple apices; 

 third and fourth purplish. Sense organ of third antennal segment 

 (pi. 16, fig. 170) with a pair of swollen curving rods, and an inner ac- 

 cessory rod, which is slender and subcylindrical or subclavate. 

 Fourth antennal segment with olfactory setae, but slightly differenti- 

 ated, however, from the other curving setae. Abdomen gradually 

 dilating. Third abdominal segment a Uttle longer than the fourth 

 (as 16:15). Genital and anal segments not ankylosed. Legs stout, 

 pale green tinged with purple. Tibiotarsi subcyUndrical, not subseg- 



