114 



Geographical distribution: The species is described from Italy (Ficalbi) later on 

 found by Edwards in England, in Germany by Martini (191 5 p. 585) and by G.W. Muller. 



The eggs of Tirniorhynchus have been described by different authors (see Dyar 

 and Knab 1910 p. 259). Further they have been thoroughly described by the said 

 authors in a special paper (1916 p. 61). The following remarks are taken from that 

 paper. The eggs of the three American species, Mansonia fasciolatus, Arrib. arribdl- 

 zagw, Theob., and perturbuns Walk, do not differ very much in shape, arrangement, 

 and manner of disposal from eggs of typical Culex species. The egg-boats float upon the 

 surface of the water, one end usually resting against an aquatic plant; still there is 

 some difference in the arrangement of the eggs of the three species. The eggs of 

 M. titillans found by Moore, are of quite another type; they are placed on the 

 under-surface of the leaves of Pistia and deposited in a mass, generally between the 

 ribs of the leaves. They are attached to the leaves with their bases very closely 

 crowded together and apparently kept by a cement secreted by the female. The 

 number of eggs in a cluster exceeds 150. Moore has observed directly that at least 

 the abdomen was submerged when ovipositing. "The lower half of her abdomen 

 was submerged and bent or curved back, the segment somewhat extended, and was 

 being moved slowly from side to side; the eggs seeming to issue forth in rapid suc- 

 cession and to be as rapidly set up each in its place air bubbles were en- 

 tangled in the abdominal scales and on the leaf itself. According as the cluster en- 

 larged in her direction she drew her abdomen more and more up so that when 

 sbe finished at (i,.'55 not much more than the tip of it was curved under the leaf. 

 When she first started more than half of her abdomen would have been under 

 the water. The freshly laid cluster was white". Dyar and Knab call attention to 

 the fact that the abdomen of the female of M. titillans is unusually hairy, the hairs 

 being well distributed and coarse. This is no doubt an adaptation, that by en- 

 tangling air between the hairs prevents the body itself from becoming wet while im- 

 mersed. Moore supposes that the female, when at work on Pistia, really works in a 

 globule of air, for, owing to the dense pilosity of the leaf, the under surface is simply 

 aglow with air-bubbles, so that the leaf probably rests more on air than on water. 

 The egg-shell of this species presents no special structure; it resembles that of most 

 other Culicidce. 



In the same paper Dyar and Knab describe another egg also forwarded to 

 them by Moore. The egg is furnished with a small neck from the upper edge 

 of which four pairs of horns project upon very short stalks; these horns appear to 

 consist of solid chitin and taper into a sharp point. Later on, Moore found the 

 species which laid these eggs; it was described as a new species, M. humeralis Dyar 

 and Knab. These eggs are of interest because they resemble the eggs of Nepa and 

 Ranatra; as well known, these water-bugs pierce their eggs into half decaying plant 

 material, and the crown of spines round the tip of the eggs is commonly regarded 

 as a respiratory organ. Dyar and Knab also regarded the spines of the egg of Man- 

 sonia as in some way connected with the problem of air-supply. 



