150 



Julv. 



My excuse for again bringing forward these memoranda is mj 

 hope that some or other of your readers may think it worth their 

 while to follow up this interesting subject. 



London : May, 1896. 



ON A PROBABLE SENSE ORQAN IN THE MALE OP PANORPA. 



BY ROBERT McLACHLAN, F.R.8., &c. 



In probably all species of Fanorpa on the 3rd and 4th dorsal ab- 

 dominal segments of the male there is a peculiar structure, varying 

 much in form, and often affording excellent specific characters. On the 

 4th it consists of a more or less developed spine or tooth directed 

 backward, and usually concealed under a bristly flap or projection of 

 the middle of the apical margin of the 3rd. Although I have never 

 published such a statement, I was long inclined to consider this struc- 

 ture a stridulating organ, and am not yet convinced it is not so. Dr. 

 E. P. Felt has recently alluded to it in a paper on " Scorpion Flies," in 

 the 10th Report of the New York State Entomologist (1896) . He had 

 several times seen the female nearly resting the end of her rostrum on 

 the dorsum of the abdomen of the male, and he inclines therefore to the 

 opinion that the organ on the 4th segment is connected with a gland 

 secreting a volatile oil attractive to the female. He offers this as a 

 suggestion ; its proof remains to be discovered. I may here remark 

 that Dr. Felt appears to be insufficiently acquainted with my own 

 writings on Panorpidce. He quotes from my " British Neuroptera- 

 Planipennia " (Trans. Ent. Soc. Lend., 1868) in stating that what he 

 has found to be the 4th segment of the abdomen I consider to be the 

 3rd. But he omits to say that I expressly stated (p. 209, foot-note) 

 that I followed previous authors in giving only eight abdominal 

 segments, but that " it appears probable that there are in reality 

 nine." Furthermore, in my " Synopsis of the species of Panorpa 

 occurring in Europe" (Trans. Ent. Soc. Lond., 1869), I distinctly 

 stated (p. 60, foot-note), " Panorpse abdomen censeo novem segmenta 

 habere," and in all my numerous writings on the genus since that date 

 I have always adhered to nine as the correct number. It is apparently 

 through not having himself seen my paper of 1SG9 that he has mis- 

 understood a quotation from it by Scudder (Bull. U. S. Geol. Survey, 

 iv, 1878, p. 542) respecting P. nematogaster, McLach. The " curious 

 appendage to the 3rd joint " of the abdomen there referred to, concerns 

 the strongly modified flap of the 3rd segment in that species, and not 

 the tooth or tubercle of the 4th. 



