34:8 PROCEEDINGS OF THE 



siphons ; they float at the surface and breathe by means of two 

 stigmata, flotation being assisted by a series of palmate hairs. 

 The larva of Taeniorhyncus obtains oxygen by piercing the roots 

 of water plants with its sharp-hooked siphon. Dr. Tierney then 

 showed a diagram of the larval heads of the three British species 

 of Anopheles, maculipennis, plumbeus, and bificrcatus, and pointed 

 out the differences. The pupa has neither mouth nor vent, and 

 the pupal stage usually lasts two or three days. Perfect insects 

 had emerged from pupae kept on damp filter paper, but if the 

 paper is dry, they die. If creosote is put on the water containing 

 nearly mature larvae, or even if a shower of rain falls on the surface 

 of the water, the larva changes more rapidly into the pupal state, 

 and the duration of the pupal stage is shortened. The impreg- 

 nated females of Culex hibernate on dark walls, etc. : they 

 frequently congregate in the tropics on dark clothing, and many 

 may be found in old boots. White clothes are avoided, probably 

 because the insects would be more easily seen. Only the female 

 mosquitoes suck blood. Culex is distinguished from Anopheles 

 by its short palps, those of Anopheles being practically as long as 

 the proboscis. The spots on the wings of Anopheles maculipennis, 

 caused by groups of scales, are also present in Theobaldia. Culex 

 and Anopheles may be distinguished by their resting positions. 

 Anopheles keeping the abdomen in the line with the proboscis, 

 while Culex assumes a more humped position. C. pipiens and 

 A. maculipennis are domesticated species, while A. bifurcatus and 

 A. plumbeus live in the open. The fertilised female of A. maculi- 

 pennis hibernates in cowsheds, cellars, etc., and emerges from 

 hibernation in March. Its favourite breeding places are the 

 shallow margins of weedy (not foul) calm open waters. A. plum- 

 beus is a sylvan species, and lays its eggs only in the water in tree 

 holes. Eggs laid in autumn do not always hatch until the 

 following spring. This species also hibernates as a larva. Dr. 

 Tierney then described the vessels used for breeding purposes. 

 Glass jars half filled with water and having gauze covers are used, 

 the pupae being separated from the larvae every day. The 

 imagines take an hour or two to dry, and they are allowed to stand 

 on some suitable support in a bottle or large test-tube. They may 

 very conveniently be kept in wide-mouthed bottles with hollow 

 stoppers. These are kept upside-down, the stopper being filled 

 with water on which floats a thin piece of cork somewhat smaller 



