504 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



flow, since the back water arrests the downward current and event- 

 ually forces the water back, thus completely filling the creek-beds 

 with turbid river water. In such creek-beds trees of various kinds 

 abound, as well as great masses of dead and fallen timber, too heavy 

 to be floated away. All such projecting points offer sufficient space 

 for the fly to deposit eggs upon, and such places we intend to have 

 closely investigated the coming spring at a time in which the water 

 is highest and in a neighborhood where flies are known to breed. 



As mentioned in our report for 1884, Dr. W. S. Barnard has de- 

 scribed and figured in the American Entomologist (Vol. Ill, pp. 191- 

 193, August, 1880) the eggs and early states of a species of Sinmlium 

 common in the mountain streams in the vicinity of Ithaca, N. Y. 

 These eggs (Plate VIII, Fig. 7) were found on the rocks on the banks 

 a few inches above the surface of the water, and we give herewith a 

 description of them as a means of facilitating the finding of those of 

 the southern species here treated of. The eggs are deposited in a com- 

 pact layer ; their shape is long ovoid, but on account of their softness 

 and close proximity to each other they become distorted and poly- 

 hedral ; one end is frequently flattened or concave. Each e^g meas- 

 ures 0.40™"' by 0.18""". In Hungary the eggs of the Columbacz 

 Midge (>S'. columhaczensis Schonbauer) have also been studied by 

 Edward Tomosvary, and the observations have been published since 

 his death by Dr. G^za Horv^th.* It seems that this species is, as 

 far as its habits are concerned, more intimately related to our smaller 

 species than the larger and more dangerous Buffalo Gnat. Its eggs, 

 which are enveloped in a yellowish-white slime and deposited towards 

 the end of May or beginning of June, are also deposited upon stones 

 or grass over which the water flows and in the brooks ot the more 

 elevated regions. The female of that species is said to deposit on an 

 average from 5,000 to 10,000 eggs, but no detailed description is given, 

 while we have found only about 500 in the ovaries of our species. 



But when and where does the larger and true Buffalo Gnat deposit 

 its eggs? At present nothing is known about it. Messrs. Lugger 

 and Webster left too soon to discover the eggs, because no gnats were 

 expected so unprecedently late in the season ; while Mr. Fillion did not 

 reach the affected region until too late. At the time in which the 

 Buffalo Gnat swarms all the low land is flooded and the water in the 

 bayous has reached a depth of 20 and more feet above the usual sum- 

 mer depth of 2 to 5 feet. The water at such a time has spread over 

 thousands of square miles, and only the taller trees are above it. 

 Over such an extent of surface it would naturally be almost impossi- 

 ble to find these small eggs j but it is now known that the members 

 composing the swarms of Buffalo Gnats are all females, which, led by 

 a mad desire for blood, leave their breeding-places not to return 

 again, but to perish in consequence of this appetite. To perpetuate 

 the species, therefore, copulation of the sexes must take place almost 

 immediately after acquiring wings, that is, at or near the places of 

 their birth, which latter the males do not seem to leave at all. Eggs, 

 no doubt, will be found at such places. If deposited anywhere else 

 their chances of hatching, or rather the chances of the newly-born 

 larvae remaining in the water after the subsidence of the same, would 

 be slight indeed. 



It admits of but little doubt that the eggs will hatch very soon 

 after being deposited, for it is not likely, as has been claimed by 



*A. Kolumbacsi legy, Dr. Horvath Geza, in Rovartani Lapok, I. Kotct, 10. 

 fuzet, Budapest, 1884. 



