376 



enveloped in a cloud of the Hippelates, and iu passing liim some 

 hundreds of the flies now follow yon. 



If it lias been proven that infectious diseases are disseminated by 

 mosquitoes, house flies, and other flies, the danger arising from the 

 Hippelates as carriers of contagious diseases is perhaps more evident 

 than in many other cases on record.* Mr. II. G. Hubbard, Avho has 

 passed many summers in Florida, reraailvcd on this point '"that in 

 Florida a serious disease of the eyelid is often prevalent. It is known 

 as 'sore eye' and becomes absolutely epidemic from time to time. He 

 feels certain that this Hippelates carries the disease, since it is well- 

 known that even the use of the same handkerchief will convey the dis- 

 ease froni a sore-eyed pf^'son to a healthy one. He has known it to start 

 with a single person and run through an entire school or communit}^, 

 and he thinks Hippelates alone accounts for the rapid spread. More- 

 over, the irritation caused by the flies greatly aggravates the disease, 

 which becomes very serious, the i)atient seldom recovering entirely 

 from it, being affected by weak eyes ever afterwards." t This danger 

 of diseases being carried by the flies exists not only between man and 

 man, but also among domestic animals and between man and animal. 



Geographical distrihution. — The Hipi)elates plague reaches, iu my 

 experience, its maximum height in Florida, but I also encountered the 

 flies in annoying numbers at Sehna, Ala., and Columbus, Tex. Mr. 

 L. O. Howard observed some years ago swarms of a small fly greatly 

 annoying his dog, in the vicinity of Washington, and fortunately col- 

 lected and i)reserved specimens ; finally jMr. C. L. Marlatt reports a sim- 

 ilar experience near the same place. The meager material thus collected 

 was submitted to Mr. Ooquillett and was found by him to represent 

 three species. The species from the District of Columbia collected by 

 Mr. Howard, II. favijjes Loew (Fig. 37), proved to be identical with 

 that observed at Crescent City, Fla., and judging from memory, the 

 same species occurs at Selma, Ala. Specimens collected at Bartow, 

 Fla., were determined by Mr. Coquilletfc as H. pusio Loew, while those 

 found by the writer at Columbus, Tex., and by Mr. Chittenden at 

 Rosslyn, Ya., proved to be II. plebejus Loew (Fig. 38). It is safe to 

 assume that other species of the same genus will be found to possess 

 the same habit, but since these small flies have never been carefully 

 collected nothing definite is known at present regarding the geo- 

 graphical extent of any of their species. All that can be said at 

 present is that the genus Hippelates seems to be confined to the more 

 southern i3ortions of the couutrj'.l 



* The literature on the subject appears to be quite extended but is not readily 

 accessible. Most of the articles which I was able to consult deal with the dangers 

 arising from house Hies and mosquitoes, but it is evident that the writers on the sub- 

 ject of ophthalmia refer to other species of Diptera, though no names are given. 



t Proc. Ent. Soc. Wash., vol. iii, p. 179. 



+ Osten Sacken's Catalogue enumerates two species from Texas, one from the Dis- 

 trict of Columbia, one from Illinois, four from Cuba, and one from California. The 

 latter locality is open to doubt. 



