90 



NATURAL HISTORY. 



prominent, consisting of a short basal and long second joint. In general form the insects are rather 

 slender, with a long abdomen ; the legs are slender, with three pulvilli on the tarsi ; the wings have 

 one complete cell on the disc. 



These insects are generally of moderate size, and frequently have the wings spotted. They are 

 found during the summer in meadows, about hedges, and in woods. They are sluggish in their 

 habits, and the larger species are commonly found sitting on the trunks of trees, always with their 

 heads downwards. They sometimes prey upon other insects. The larvae live in the ground, in 

 sand, manure, and decayed wood ; and that of one species (Leptis vermileo) is described as making 

 small conical pitfalls in the sand, for the purpose of entrapping small insects, after the fashion of 

 the Ant-lion. The habits of another species (Aiherix ibis), not uncommon in Britain, are still more 

 curious. The fly, which is about a third of an inch long, is of an ash-grey colour, with transparent 

 wings thickly covered with more or less confluent brown spots. The females are gregarious, and 

 attach their eggs in large pear-shaped clusters to boughs overhanging streams of water. The cluster 

 is formed by the contributions of numerous females, which remain on the spot and die there, and 

 when the larvae are hatched they fall into the water, which is their future residence. 



FAMILY XVI. DOLICHOPODID^E. 



This is a numerous family of small flies generally adorned with bright metallic colours, which 

 in some respects seem to form a passage to the next tribe. They have three-jointed antennae, short 

 or of moderate length, but prominent, and the third joint, which is either oval or pointed, has a 

 bristle springing either from its extremity or its back. The proboscis is short, thick, and fleshy, and 

 contains only one bristle, the maxillae being united with the labrum, although their palpi, which 

 consist only of a single joint, are of considerable size. The labrum is large and horny. The head 

 is of moderate size ; the eyes usually separate in both sexes ; the ocelli distinct ; the legs long and 

 thin, but often showing very curious developments of certain parts, especially the tarsi, which have 

 three pulvilli, of which the middle one is smaller than the others ; and the wings have only five 

 longitudinal veins, with a cross vein uniting the fourth and fifth. The structure of the abdomen in 

 the males is very peculiar. It is composed of six segments, and its apex is bent forward, and 

 furnished with an extraordinary variety of copulatory appendages. The larvse are long, slender, and 

 cylindrical, and live in the ground or under the decaying bark of ti-ees ; they have the last segment 



thickened, and furnished with two tubercles above, each of 

 which bears a stigma. The pupa is found in the same situa- 

 tions as the larva, and is free, with two curved horns on 

 the thoracic region and rows of bristles upon the segments 

 of the abdomen. 



In their habits, notwithstanding the imperfection of 

 their mouths, the Dolichopodidae are all predaceous ; in this 

 respect resembling some of the Empidse, with which they 

 would seem to have considerable relationship. They are 



IJt /jrll^t \St found running about, backward, forward, and sideways, upon 



^ . ygl ^ ^^ the leaves of plants and trees, from which they are said to 



be fond of licking the honey-dew ; and they also frequent 

 the trunks of trees, walls, palings, &c. ; but many of them 

 haunt the neighbourhood of water, and seize insects, and 

 even small worms and mollusca, when they come to the 

 shore. Some of them actually venture upon the water in 

 pursuit of prey, running freely upon the surface, after the 

 manner of those curious long-legged Bugs (Gerrls) whose 

 movements must be familiar to every one. One genus has 



received the name of Hydrophorus from this circumstance, and they not only frequent the 

 surface of lakes and ponds, but even venture on the sea. These and some others have the 

 fore legs fitted to act as raptorial organs. The prey, when seized, is readily admitted into the gaping 

 orifice at the extremity of the short proboscis, and held fast there while its fluids are being sucked out. 

 Many of the species live in the vicinity of the sea-coast 



A, DOLICHOPUS DISCIFER. B, SIDE VIEW OF THE 

 EXTREMITY OF THE ABDOMEN OF THE MALE. 



