NORTH AMERICAN DIPTERA. 229 



American group, being represented, as far as known, by only one 

 species within the United States — S. comtaris Loew, Texas. I pro- 

 pose for this the group matablle from its typical and widest distributed 

 species, S. mntabilis Fabr. 



Of the life habits of the American species little is known. Dr. 

 Williston (Standard Nat. Hist. vol. ii, page 416) gives the following 

 account : " The larvae lives in water, earth, or decaying wood. Those 

 of a species of Stratiomyia are known to inhabit some of the western 

 alkaline lakes, and a European species is found in salt water. The 

 transformations of S. chameleon in Europe are well known. The 

 eggs are deposited by the female in layers overlapping each other on 

 the under side of leaves of aquatic plants. The larvae are naked, 

 smooth, broader in front, where there is a small head ; the sides of 

 the abdominal segments are provided with a hook-like foot process. 

 The last three are much narrowed and elongated, the terminal are 

 especially so, and at its tip with a circlet of hairs surrounding the 

 stigmata. When they breathe these hairs enable the larvae to keep 

 themselves at the surface, and by their means, when folded, they can 

 retain a small bubble of air and carry it with them beneath the sur- 

 face. Their food consists of very small aquatic organisms. They 

 swim about in vertical, undulatory motions. The pupae are enclosed 

 in the anterior end of the larval skin, which enables them to float 

 about freely in the water. They escape at maturity through a slit 

 in the back which has become exposed to the air." The perfect in- 

 sects are generally found on flowers, and are noticeably more numer- 

 ous in the vicinity of streams and ponds. 



The following note from a recent article by Prof. Lawrence 

 Bruner {Evening Call, Lincoln, Neb., April 5, 1895) on the peculiar 

 habit of a Stratiomyid larva may prove of interest. The specimens 

 were found by Mr. John C. Hamm in the thermal springs of Ninta 

 County, Wyoming. * * * "At the time I saw the larvae in their 

 native habitation I did not have a thermometer with which to take 

 the tempei'ature, but the water was so hot where I saw them I could 

 not hold my hand in it. My best judgment is, and was at the time, 

 that the water was not more than twenty or thirty degrees below the 

 boiling point." * * * " In color they are dull gray, in form much 

 flattened, and in size the length of the line below the figure (15 mm. ). 

 The two specimens examined by me are more or less incrusted with 

 sulphur and other mineral substances." 



The number of species recorded froni North America, in Osten 



TRANS. AM. ENT. SOC. XXII. JULY. 1S95. 



