The Culicidce or mosquitos or gnats belong to the nematocerous section of the suborder Orthorhapha of the order Diptera, or flies. Nearly allied families are the Simuliidae or sand flies, the Chiron omidce, or midges, and the Psychodidce, or owl midges. The relationships of these blood sucking flies will be evident from the table on p. 131.
We can here define only briefly the characters of the main divisions, treating at greater length the subfamily Anophelince. For an adequate description of the Culicidae, Theobald's monograph of the Culicidce should be consulted.
Diptera: (1) Two wings. (The posterior wings are represented by a pair of halteres, clubbed structures on a stalk.) (2) They have a suctorial mouth. (3) They undergo a complete metamorphosis, eggs, larvae, pupae, imagos.
Orthorhapha: Larvae have a distinct head. The larval skin bursts to allow the escape of the pupa or imago by a T-shaped opening at the anterior end. These points distinguish the Orthorhapha from the Cyclorhapha.
Nematocera: Antennae with 6 or more segments, palpi slender, 4 or 5 segments, thus distinguished from the Brachycera, which have short antennae and palpi.
Chironomidoe: Midges-small slender flies. Wings not scaly. Costal vein does not extend beyond the apex of the wing. Antennae filiform. Densely plumose in male. Proboscis not projecting. Egg laid in ropes enveloped in mucus. The whole development of the egg in temperate climes takes three to six days.
Psychodidce (owl midges): Owl midges or moth flies. Minute, densely hairy flies, so easily distinguished. Proboscis short; longer in Phlebotomus. Wings in resting position meet like the sides of a roof. The larvae are cylindric and have a short spiracle. The pupae have siphons (tubular stigmata).
Simuliidce (sand flies): Small, humpbacked flies. Antennae short, destitute of hairs. Proboscis not projecting. Legs short, with flattened femora. Palpi 4-jointed. Wings broad. All the veins except the anterior ones very delicate.
3. Cidicidae (mosquitos or gnats).
Anopheles, Myzomyia, Stethomyia, Cyclolepidopteron, Pyretoph orus, Arribalzagia, Cellia, Christya, Myzorhynchus, Nyssorhynchus, Lophoscelomyia, Aldrichia.
Culex, Janthinosoma, Psorophora, Mucidus, Desvoidea, Stegomyia, Scutomyia, Macleaya, Danielsia, Leicesteria, Katageiomyia, Eret mapodites, Skusea, Howardina, Finlaya, Theobaldia, Lutzia, Gile sia, Lasioconops, Melanoconion, Grabhamia, Acartomyia, Tcenior hynchus. Mansonia. Hidoccetomnia. Aedimorphus. Verrallina.
Megarhinus, Toxorhynchites. Joblotia.
Deinocerites, Aedesy Ficalbia, Uranotcenia, Mimomyia, Aedeomyia, Hcemagogns, Wyeomyia, Phoniomyia, Dendromyia, Runchomyia, Sabethes. Sabethoides. Goeldia. Limatus. Hodaesia.
4. Psychodidce (owlmidges) .
5. Simuliidce (sandflies).
1. Tabanidce (horseflies) .
Both these latter flies will pass through an ordinary mosquito net, which, however, bars their egress when gorged with blood.
Larvae blackish, aquatic, about half an inch long, attached to the under side of water weeds and to stones, etc. The larvae are cylindric and have "shaving brushes" for sweeping food into the mouth. The larvae have two pairs of legs. Each pair is greatly modified to form a sucking organ. The motion of the larva is an alternate fore and aft one, like that of a leech, produced by means of their suckers. The pupae build for themselves cocoons attached to aquatic weeds.
Culicidce (mosquitos): Easily distinguished by the fact that the proboscis is long and projecting. Head and thorax of larvae distinct; well developed tracheal system. Eggs laid singly or in rafts.