October 1897.] 



PSYCHE. 



127 



to the east of the !MesilIa Valley of the 

 Rio Grande. Data on the life-zones of 

 these mountains are given in that article, 

 and are revised somewhat in Transac- 

 tions Texas Acad. Science., i, p. 79. 

 A popularly written sketch of a trip to 

 the Organ Mts. is given by Mr. Charles 

 H. Ames in Appalachia for 1S92. If 

 the reader W\\\ take the trouble to look 

 up and familiarize himself with this lit- 

 erature, he will have a fair idea of the 

 more important topographical features 

 of these mountains. While not exten- 

 sive in area, they constitute a region of 

 much interest from a biologic point of 

 view. Their highest peaks reach to an 

 elevation of S,Soo ft. above the level of 

 the sea. 



I . Eupeodes vohicris OS. One 9 . 

 Dripping Spring, Organ Mts. About 

 5600 ft. August 10. Length, SJ mm. 

 Legs reddish, bases of all the femora 

 black, hind femora with but little more 

 black than others, knees narrowly yel- 

 lowish. Stigma of wings very pale 

 yellowish, as is whole space between 

 auxiliary and first longitudinal veins. 

 Strange to say, there is some scattered 

 pubescence barely visible on lower half 

 of eves. No pubescence is visible in 

 many other specimens that I have exam- 

 ined. 



Also one 9 . Soledad Caiion. About 

 5000 ft. August 15. On flowers of 

 Melampodiutn cinereum DC. Length, 

 7.5 mm. Later in the season both $% 

 and 9 s were taken in the Sacramento 

 Mts. 



It is a remarkable but well-known fact 

 that the sixth segment in the $ of this 



species is always unsymmetrical, and 

 points to the right. So far as I know, 

 the case is without parallel among the 

 diptera. The asymmetry consists in 

 the left lateral margin being oblique and 

 nearly in a straight line with tlie left 

 lateral margin of the fourth and fifth 

 segments ; while the right lateral margin 

 is evenly rounded in outline. The seg- 

 ment is thereby thrown out of line with 

 the longitudinal axis of the abdomen, 

 and is left pointing to the right. 



2. Zodio7i splendens Jaenn. One 

 t? . Soledad Canon. About 5000 ft. 



August 15. On flowers of Zinnia 

 grandiflora Niitt. This is a large 

 specimen, measiu-ing it mm., and is 

 very pronounced in its markings and 

 coloration. The face and front, except 

 vertex, are unicolorous, both being of 

 the same clear light yellow tinge. The 

 foin^th abdominal segment is wholly 

 pollinose, except the pair of oval spots. 

 Scutellum pollinose on whole upjJer 

 smface. 



3. Zodion fulvifi'ons Say var. 

 abdominale Say. One 9 . Soledad 

 Canon. About 5500 ft. August \^. On 

 flowers of Pedis papposa Gray (det. 

 Ckll). Length, nearly 7 mm, Front 

 silvery dusted along orbits, yellow, red- 

 dish-yellow at vertex. Thoracic dorsum 

 with a third, or median, more slender 

 brownish stripe. Second abdominal 

 segment nearly all yellow, hind border 

 brownish, and a faint median line pale- 

 brownish. Anterior corners with a tuft 

 of lilack hair. First, third, and foijrtb 

 segments brownish ; sixth and basal 

 half of seventh reddish-yellowish ; all 



