from the Rio Nauila^ State of Vera Cruz. 23 



Conopidae. 



Stylogaster. 



Fifty-one specimens of this interesting genus were taken 

 hovering over the front ranks of a moving army of ants, in 

 a cafetal at Paso de Telaj^a, during the L^st hour or two of 

 daylight on March 29. In company with them were nume- 

 rous specimens of Hi/alomyia and some other small tachinids. 

 The ants have been determined by Mr. Theo. Pergande as 

 Eclton Foreli^ ]\Iayr. Mr. Pergande adds that they are the 

 most northerly form of that species, which is a widely dis- 

 tributed one in the American tropics. The column of ants 

 was about 15 feet wide and 25 feet long, and moved slowly 

 but surely in a straight line through the cafetal^ swarming 

 rapidly over the thick covering of dead leaves, branches, and 

 other obstructions that strewed the ground under the coffee- 

 trees. The specimens of Stylogaster hovered continually 

 over the ants, now and again darting at them, without doubt 

 for the purpose of ovipositing in their bodies. During the 

 whole three months of my collecting in this locality, 1 saw 

 not a single specimen of Stylogaster at any other time; but 

 on this occasion, during the short time that I had before dark 

 overtook me, I succeeded in capturing fifty-one specimens, 

 by sweeping closely with the net over the front ranks of the 

 ants. These fifty-one specimens belong, strange to say, to 

 three new species, all distinct from hiannulata, Say, and 

 neglecta^ Will., the only species hitherto known from 

 America. The genus has never before been recorded from 

 Mexico or Central America. No specimens were contained 

 in the Biol. Centr.-Amer. collections, as evidenced by the 

 genus not being mentioned by Dr. Williston in his treatment 

 of the Conopidaj. 



"VVilliston has stated (Trans. Conn. Acad. 1885, p. oS9) 

 that this genus, " it is thought, may be parasitic upon 

 termites." However this may be, I believe that my obser- 

 vations, as above detailed, leave no doubt that the three 

 species described below are parasitic upon ants of the genus 

 Eci'ton, in the State of Vera Cruz. 



Such a series of specimens as the present could not fail 

 to throw some light on the confusion existing witli regard 

 to the described species, and especially to the specimens 

 described by Wiedemann, although I think that Dr. Wil- 

 liston has presented the latter question in its true light in 

 his most recent paper on Stylogaster (Kans. Univ. Quart, i. 

 pp. 120-122). I believe there is no doubt that Wiedemann 

 had two, and perhaps three species before him, one of these 



