from the Rio yautia, Slate of Vera Cruz. 285 



second segment are obsolete, as in Williston's specimen from 

 St. Vincent. No reliance can be placed on the character of 

 the apical cell being petiolate, nor can the extent of the pollen 

 on the abdomen be n-licd upon. These forms might be con- 

 sidered varieties, though it would be hard in that case to 

 decide where to stop defining varieties and recognize mere 

 individual variations. 



C. propinqiia, Wulp, if a female as designated, is at least 

 a good variety, bearing the same relation to occidua that 

 exists between imviaculata and Pallasii. But the colour of 

 the antennas and palpi is of comparatively no importance. 



C. griseonigra^ Wulp, is probably a variety of Pallasii. 

 But it is useless to speculate on descriptions not exceeding 

 two to four lines, except in so much as they indicate what is 

 still to be found and described. I will not attempt an ex- 

 amination of Wulp's male Cistogastera, Avhich all seem easily 

 referable to either occidua or immaculata, though, of course, 

 nothing can be said of them in their present incompletely 

 characterized state. It is greatly to be regretted that such a 

 long delay, though doubtless unavoidable, in the appearance 

 of the parts of the ' Biologia Centrali-Americana ' should have 

 caused the publication separately of such short diagnoses of 

 species. The diagnoses, if presented separately in advance, 

 should be full and complete. 



It may be noted here that Cistogaster is another of those 

 tachinid genera which are not at present known to occur in 

 New Mexico. 



Phaniidse. 

 44. Xanthomelanodes arcuata, Say. 



Four males and four females. Paso de Telaya, one female, 

 March 28, and two females, April 7. San Rafael, one female, 

 June 20, in sweepings. The males, all San Rafael, on flowers 

 of the Cordia sp., June 29 and July 5, 12, and 16. 



Length of males 5 to 7 millim.,of females 5 to 6^millim. 



The allied X. atripennis was described by me in Notes 

 N. Amer. Tachin. i. pp. 145-146, as a Wahlbergia. The 

 latter genus should be known as Besseria. The present forms 

 are very distinct from Besseria, lacking entirely the peculiar 

 female abdominal characters of that genus, besides differing 

 widely in other respects. 



The present specimens of arcuata vary considerably in 

 size, two of the males (July 5 and 16) and two of the females 

 (March 28 and June 20) measuring only 5 millim. ; but they 

 hardly differ in coloration, and are without doubt all the same 



