1917] Camptopelta 25 



However, it is a question how much reliance can be placed 

 in this family upon the absence of this branch. This vein is 

 disappearing in this family, and it is a well known fact that 

 disappearing organs are more or less inconstant in the individual, 

 just as the wisdom teeth often are not erupted in the human 

 individual. In Odontomyia, Oxycera, and other genera of the 

 family its presence or absence is disregarded as a generic or even 

 .specific character; I am very skeptical of any genus that is 

 based upon its absence exclusively, and that seems to be the 

 condition in some of the more recently described genera of the 

 Pachygastrinae. So also, the origin of the fourth vein is not 

 absolutely fixed in all genera. 



In the latter part of May I found a species of Geron (Bom- 

 byliidce) very abundant on several kinds of flowers in the canons 

 of Mt. Socorro, and a little ways out on the plains. I could 

 have collected hundreds of specimens had I chosen. I did 

 capture enough, however, to show that about one in every 

 twenty had a perfectly formed third submarginal cell. I could 

 discover no other constant differences. Whence it follows that, 

 in the definition of this and some other genera of the Bombyliidas, 

 as in several genera of the Stratiomyidae, the number of submar- 

 ginal cells does not have even a specific value. This species of 

 Geron is a "sport" or "mutation" that has not yet been fixed 

 by heredity, a developing character, apparently. Rhabdop- 

 selaphus Bigot was based upon a difference of the third antennal 

 joint {Gero7i trochilides W. probably belongs with it) and with 

 " submarginalibus tribus" cells. One of its type specimens in 

 Mr. Verrall's cabinet has but two submarginal cells, but it is 

 not at all sure that this genus also is not variable, and that 

 Bigot made a mistake in his description. 



Mr. Malloch, though he has never seen a specimen of 

 Lophoteles, has expressed a doubt of the correctness of my 

 generic determination of L. pallidipennis W.* Perhaps it is 

 presumption on my part, in view of Mr. Malloch's knowledge of 

 the family, to adhere to my opinion. Indeed, I long had a 

 suspicion that not only was my species congeneric with Loew's 

 type but that both species were identical! And this suspicion 

 has been increased by Enderlein's discovery f of L. plumula 

 Loew in Costa Rica! About the only difference he finds 



*Annals Ent. Soc. Amr. 1915, p. 335. 

 fZool. Anz. 1914, p. 311. 



