10 



frontal tufts. In some species, 0. prodotes and caspius, the number of hairs in both 

 tufts is restricted to one single long hair; Finlaya geniculata has two in the upper and 

 one single hair in the lower frontal tuft. In Tceniorhynchus Richardi the upper fron- 

 tal tuft is lacking; in T. annulata we find an additional lateral, strong, tuft in the 

 notch between eyes and antenna. Often and especially in Tceniorhynchus we find 

 small multiple tufts between the above-named larger ones; these tufts are not marked 

 because they are rather inconstant. The epistome has often drawings, different 

 among the different species, but remarkably constant in the same. I refer especi- 

 ally to the tables of T. annulata, 0. rusticus a. o. The colour of the epistome is com- 

 monly either grey or yellowish red. When in spring the drying ponds in our 

 woodlands teem with the large, grey larvae of 0. communis, prodotes a. o., ready to 

 pupate, we almost always find, scattered in the swarms, many, smaller larvae diffe- 

 ring by their yellowish red heads from these larvae; these larvae with red heads 

 belong to 0. cantans which will shortly, when the others have disappeared, pre- 

 dominate in the ponds. 



The mosquito larvae have commonly two pairs of compound lateral eyes, ocelli, 

 like those of other aquatic insect larvae, being absent; in the Tceniorhynchus larvae, 

 living at the bottom of the ponds, between the roots and almost in total darkness, 

 we find only a single pair of very small eyes. The outer form of the two pair of 

 lateral eyes is different in the different stages of the larvae; in the same species 

 they are often almost separated by a narrow band; the posterior pair has as a 

 rule not been marked in the figures. 



The Antennae consist of a single piece; they are remarkably stiff and possess 

 only very slight mobility; their length differs greatly, commonly they are half as long 

 but often as long as the head; in F. geniculata they are extremely short, only one 

 fourth of the length of the head; in some species, as C. pipiens and C. nigritulus, 

 they are longer than the head, and in Culicella morsitans and Tceniorhynchus Richardi 

 more than three times longer. In the short antennated species the antennae are 

 almost straight, only slightly curved. Where the antennae are very long, they are 

 especially, as in C. morsitans, elegantly curved, forming together two large, down- 

 ward directed arches before the head. The antennae always taper at the apex and 

 in the middle of the shaft or about two-thirds from the base of the shaft, often, in a 

 constricted part of the antenna, is inserted a fan-shaped tuft of long, commonly 

 feathered hairs. In Ochlerotatus, Theobaldia and Aedes cinereus they are inserted 

 directly on the antenna, in Culicella on a conspicuous notch. The development of 

 the tuft is very various; in Finlaya geniculata it consists of only one single un- 

 feathered hair; commonly, as in most species of the gen. Ochlerotatus it has only 

 from five to seven hairs; but in Culex pipiens, C. nigritulus, Culicella morsitans, 0. 

 diant&us and Tceniorhynchus the number is from twenty to thirty; here too, the 

 single hairs are very long, forming in these species two large wheels with feathered 

 spokes. When the larva is hanging from the surface or from a plant, the tuft is 

 always folded out; a movement of the single rays is rarely observed, but I have 



