1S77.J 127 



it : that is, instead of a Muscid, with a silvery head or abdomen, I had 

 before me a small, dull greyish male Hilara. At the same time, how- 

 ever, I . perceived on the gauze of my forceps, not far from the fly, a 

 flake of opaque, white, film-like substance, oval, about 2 mm. long, and 

 so light, that tlie faintest breath of air could lift it. The appearance 

 of this film was not unlike that of the opaque, white tissue spun by 

 some spiders ; but for its much lesser weight, it might also be com- 

 pared to the petal of a small white flower. I caught several specimens 

 in succession, with the same result. It became evident to me that the 

 silvery reflection, as well as the apparent larger size of the fly, when 

 on the wing, were due to these bits of white tissue, which they waved 

 like flags behind them. 



What is the purpose of this performance ? How do the flies hold 

 these flags : with the legs, pressed against the abdomen, or with the 

 forceps of the hypopygium ? Where do they obtain these flakes ? 

 Is it, perhaps, a portion of their cocoon ? Is it a habit peculiar to 

 this species, or, has it been simply overlooked before, and is of more 

 common occurrence ? Such are the questions which naturally suggest 

 themselves in presence of this phenomenon. 



I repeated the observation on several other days, but had no 

 opportunity for further investigations. 



Prof. Loew, whom I recently visited in GTuben, had the kindness 

 to name the species for me. It is the Hilara alpina, Loew, of his 

 collection, a name which seems to prove that the species is peculiar to 

 the alpine region, and not one of the common European Hilarae. He 

 told me at the same time that, several years ago. Prof. Zeller had com- 

 municated to him a somewhat similar observation. 



Prof. Zeller, to whom I wrote on the subject, kindly informed me 



that he observed the same phenomenon on the 14th of August, 1873, 



between the villages Latsch and Stuls, above Bergiin, Canton Grisons, 



at an altitude of about 1600 metres ; and his observation seems to 



agree with mine in every respect, except that he first perceived the 



flies gyrating in a shady 'place. 



Frankfort-on-Main, 



October, 1877. 



EEMAKKS ON SOME BRITISH IlEMIPTERA-lIETEROPTERA. 



BY O. M. REUTER. 



(Continued from page G2j. 



LiTOSOMA ViRESCENS (Cat., 31, G) is cited by Mr. Saunders 



(Synops., 293, il) as being the male of concolor. Mr. Douglas has 



