REPORT OF THE ENTOMOLOGIST. 505 



some, that the eggs will remain dormant for a whole year, or even 

 two and more years, in the place where deposited, only to hatch when 

 reached by another overtlow. Snch theories are not borne out by 

 any observed facts, and they are, moreover, contrary to the usual 

 habits of similar insects. 



Since some of the breeding places of the two species of insects are 

 now well known, the finding of the eggs will only be a question of 

 time. 



The Larva. — The peculiar aquatic larvae of both the Buffalo and 

 Turkey Gnats resemble those of the other known species, and their 

 distinctive features will be shown in the closing descriptive portions 

 of the paper. Generally speaking, they are less than half an inch in 

 length, subcylindrical, attenuated in the middle, and enlarged toward 

 both ends; the posterior third of the body is much stouter than the 

 anterior third, and almost club-shaped. The color of the larva varies 

 greatly, and is usually more or less like that of the substance upon 

 which it is fastened; it is marked by two dirty, greenish-gray, irreg- 

 ular spots upon each joint, on a whitish and translucent ground. The 

 head, which is almost square, is yellowish, marked with a few darker 

 spots and lines, and with a pair of small, black, approximate spots on 

 each side that look like eyes, but are not. Besides the usual mouth 

 organs the head possesses two additional brown and fan-shaped bodies, 

 which are usually spread out and kept in constant motion Vv^hen catch- 

 ing food; they open and close like a fan, and if folded can be par- 

 tially withdrawn into the mouth. The smooth body of the larva is 

 comi30sed of twelve joints or segments, five of which form the club- 

 shaped anal portion of the body. On the under side of the thoracic 

 portion there is a subconical, retractile process, crowned with a cir- 

 cular row of short and sharp bristles. The anal extremity consists 

 also of a subcylindrical, truncated protuberance, which is crowned 

 with rows of bristles similar to those of the thoracic proleg. The 

 larva possesses no stigmata, but immediately below the anal pro- 

 tuberance, on the under side of the body, there are three short, cylin- 

 drical, soft, curved, and retractile tentacles, to which the large tracheae 

 lead, and which are probably the organs of respiration. 



In some of the most mature larvae two kidney-shaped black spots 

 are visible just above the thoracic proleg, one on each side. If closely 

 investigated with a good lens it is seen that the tufts of filaments serv- 

 ing the future pupa for respiration are already formed under the larval 

 skin. All these filaments arise from the same spot and are branches 

 of a single internal tube. 



Hahiis of the Larvce. — The larvae of the different species of Simu- 

 liiim are so very uniform in their modes of life that the description of 

 the habits of one will suffice for all. 



The most essential condition for the well-being of these aquatic 

 creatures is rapid motion of the water in which they live. Wherever 

 water of such a description is found in the region infested by Buft"alo 

 and Turkey Gnats the one or the other species can be found. 



The next important condition of a suitable breeding-place is the 

 presence of some stationary material in the water upon which to fasten 

 themselves. 



Water in rapid motion is only found in certain well-defined places, 

 either in streams coming from an elevated plateau or in streams mean- 

 dering through a level country. In the former any sudden bend and 

 any obstruction, no matter how small, will produce accelerated motion 

 of the water; in the latter, sudden bends are the chief cause. In the 



