10 JAMES WATERSTON. 



It was also in Dr. Joyeux' Serbian collection. The larvae were generally found in 

 shaded situations. This species was never in my experience met with in tents or 

 dug-outs, nor was any instance of its biting brought to my notice. 



Culex pipiens, L. 



So far as was observed, this is the most widely spread mosquito in Macedonia,, 

 occurring wherever one collected ; no special localities need therefore be indicated. 

 Larvae were found from sea-level up to 800 metres (near Nicolson's Neck), the 

 highest point at which investigations were made. The females oviposit both in clean 

 and foul water. Larvae were collected from pools in hill streams, at the sides of the 

 Vardar, round the margins of lakes, in horse-troughs, water-logged tins, hoof-marks 

 on lake margins, etc. As a rule slack water with plenty of algae was preferred, but 

 larvae were found in great numbers in the following environments : — (a) In an 

 artificial washing pool about 18 in. deep and a yard across, near Hadji Bairamli, 

 throughout September. This pool was seldom clean, being contaminated with 

 organic matter and occasionally slightly milky with soapsuds, yet frequent visits- 

 showed no diminution in the stock of pipiens. There also occurred Culex hortensis, 

 Theobaldia longiareolata (abundant) and T. annulata (a few), with one or two- 

 examples of Anopheles palestinensis. (b) In November a similar association of 

 pipiens and Theobaldia annulata larvae was discovered in a larger and deeper well 

 at Mikra. No green algae were seen here, but many dead invertebrates were 

 floating on the surface, and larvae brought to the laboratory fed up rapidly on fresh- 

 chopped Musca domestica. (c) In extremely foul-smelling but quite clear rocky pools 

 of sewage- effluent in the glen below Ravna. This water turned cloudy and 

 " rotted " when kept a few days. With C. pipiens was found A. palestinensis, in some 

 numbers, (d) In a deep dug-out which was abandoned through striking a spring. 

 There were hundreds of larvae in 1 to 2 inches of water, which was perfectly clear and 

 developed no algae on standing for a week. The gut of these larvae was filled merely 

 with fine sediment from the bottom of the dug-out. The resulting imagines were 

 slightly smaller than usual, (e) One or two bred from larvae taken from a reserve- 

 tank of water said to have been regularly chlorinated. This water had been stored 

 throughout the summer, and from the early months till August the surface had been 

 oiled, and there were no complaints. In September chlorinating was substituted for 

 oiling and shortly afterwards larvae were noted. When I inspected the tanks there 

 were many small larvae, judged to be about 10 days old, moving at the surface. The 

 water in the tanks was run off, a careful examination of the contents of one of them 

 being made. There was evidence of recent chlorination of the water, and at the 

 bottom were hundreds of dead and decaying half-grown larvae. Some examples 

 from the top layer were transferred to lake water well supplied with weed, and 

 ultimately a few dwarfed specimens were bred out, in December 1917. Had these 

 larvae remained where found, it is, I think, unlikely that they would have reached 

 the imaginal condition. At the time of their first discovery, Ochlerotatus dorsalis 

 was causing considerable annoyance in camp, but its probable breeding ground lay 

 much further afield. 



C. pipiens was also found breeding in low marshy ground near the sea (Mikra),, 

 but exact tests have yet to be made of the salinity of the water in which it occurred. 



