3° BULLETIN OF THE BUREAU OF FISHERIES. 



through the burrow and out on the surface of the leaf again. This use of the same water 

 over and over, except as it is removed by evaporation and replaced by a fresh supply 

 drawn in by capillarity through minute openings, prevents the dilution of any poison 

 that may be added. Any arsenical spray should be effective. There is, however, an 

 important difficulty encountered by the lack of uniformity in the rate of development 

 of the larvae. They are present in increasing numbers from the first of the season to 

 late in September and infestation is taking place constantly. 



Where feasible the larvae may be destroyed in the early part of the season by draining 

 the pond and allowing the bottom to become dry for a few days. The larvae are unable 

 to breathe unless immersed in water and are, therefore, easily destroyed by a relatively 

 short period of drying. In small pools the mechanical removal and destruction of 

 eggs and larvae should be effective. 



DESCRIPTION OF CHIRONOMUS BRASENLE, N. SP. 



Larva. — Light green in color, the chitinized areas such as the head and claws reddish 

 brown; antennae slender, about three-quarters as long as the mandibles, the basal 

 joint four-ninths of the whole length; a small spine on the apex of the basal joint and 

 another at the apex of the second joint probably represent Lauterborn's organ. Each 

 eye consists of two black spots in such close contact as to appear as one on superficial 

 examination. The labrum much narrowed anteriorally, with a few setae and four pec- 

 tinate hairs. The epipharynx with three blunt teeth on its anterior border, the usual 

 chitinized horseshoe area laterally compressed with the usual pectinate setae, a pos- 

 teriorly projecting median process and the two lateral arms articulate with the posterior 

 margin of this area. The lateral arms also have dorsally projecting portions for the 

 attachment of muscles. They are furnished with a median projecting membraneous 

 flap. Maxilla with short palpus, several setae, and two mesad projecting lobes. Man- 

 dibles with blackened teeth, the two median and outermost teeth not much blackened. 

 Labrum with blunt-pointed margin, the teeth with rounded outline. Posterior prolegs 

 with bilobed claws. Anal blood gills long and somewhat pointed. The posterior dor- 

 sal tufts of setae are each placed upon a papilla, which is about as broad as long (fig. 

 15). There is also a pair of setae just dorsal to the anal gills. Length, 7 millimeters. 



Pupa. — Light green in color, the chitinized parts somewhat infuscated. Respiratory 

 organs consist of a pair of tufts of white filaments. Dorsal surface of the second to sixth 

 abdominal segments with a well-developed anterior band of brown setae, the second and 

 third segments with a posterior row of coarse spines, the entire surface covered with 

 minute setae, which are slightly smaller on a few irregularly placed areas, thus giving the 

 surface a slightly mottled appearance. The lateral fin of the eighth segment with the 

 usual set of four filaments and a brownish slightly toothed chitinized portion seen best 

 in the pupal molt (fig. 16). The caudal fin has the usual fringe of filaments. Length, 

 5 millimeters. 



Male. — Head, proboscis, palpi, and basal joint of antennae yellow, tubercle slightly 

 developed, eyes black. Antennal shaft and verticils brown. Antennae with 14 joints, 

 the terminal two-thirds as long as the rest of the antennae. Pronotum projecting lat- 

 erally, but not reaching the level of the mesonotum dorsally. Mesonotum greenish 

 yellow, translucent, somewhat pruinose; vittae of a light buff color; scutellum and 



