CHAP. XI - Diptera

Summary

Order 22.. Diptera. True Flies

One pair of membranous wings attached to mesothorax, the second pair represented by halteres or ‘balancers’ borne by the metathorax. Mouth parts suctorial, sometimes adapted for piercing. Larvae legless. Metamorphosis complete.

This is a very large order of insects and is one which closely affects man in many spheres of his activity.

Sub-order A. Orthorrapha

Series I. Nematocera

Family Tipulidae. ‘Daddy-long-legs’; Crane Flies

Large flies, antennae long, many-jointed, legs long and fragile. Head prominent, rounded without ocelli, there is a V-shaped suture present on the dorsal surface of the mesothorax. Ovipositor horny and valvular.

Tipula paludosa Meig. Marsh or Allied Crane Fly

DESCRIPTION. Adult. (Fig. 40.) Male. General colour grey with a reddish brown tinge. Head ashy, proboscis tawny, palpi brown; antennae 13-jointed, dark, first two segments testaceous. Thorax reddish brown, somewhat raised with four indistinct stripes, metathorax and pectus whitish. Halteres whitish and rather long. Abdomen ferruginous to reddish yellow, dorsal stripe faint, upturned at the extremity. Wings rather narrow with a reddish tinge, brown along the costa, an indistinct pale streak under costa. Legs brown, rather stout for a Tipulid; femora and tibiae blackish at tips; tarsi dark.

Female. Wings shorter than abdomen which is long and pointed, ovipositor pale brown, no wing streak. Length 17-25 mm.

Egg. Black, unsculptured, with a purplish metallic lustre, spindle-shaped, somewhat asymmetrical one end being slightly conical, the other rounder. 01dham(8) considers the micropyle to be represented by a small circular patch near the pointed end. Size I-I x 0·4 mm.

Larva Much of the information concerning this larva is derived from the work of Renniefo). The young larva is pale sandy red in colour, and the 13th segment bears a pair of tufts of relatively strong curved bristles, these tufts constitute a point of difference between the early and late stage larvae. The full-grown larva is brownish grey in colour with numbers of irregularly placed black dots. In shape it is cylindrical, slightly narrowed anteriorly and expanded posteriorly. The tough, usually tense, skin has numerous transverse wrinkles, with the segments marked off by slight furrows, each segment bearing on its ventral surface four minute bristles. The head bears a pair of short jointed antennae and a strong ehitinous mouth armature.