THE SIR AT 10 MY IV JE. 83 



of them would appear to be the Columbatsch Fly (Sitnulium columbatsckense), which inhabits 

 parts of Hungary and of the regions bordering the whole lower coarse of the Danube, occurring 

 in swarins, and attacking both men and cattle so vigorously that the latter, at any rate, often 

 succumb to the injuries inflicted by their seemingly insignificant assailants. The transformations 

 of these insects take place in the water. The larva of the common British species (V. reptans) is a 

 curious little creature of a cylindrical form, with the body rather thinner in the middle ; the head 

 is distinct, and bears a pair of short antennae, and a pair of singular fan-shaped appendages, the 

 office of which is perhaps respiratory ; the thoracic part has a stout retractile tubercle beneath ; 

 the end of the abdomen has several curved appendages. This larva lives on the sub-aquatic stems 

 of Phellandrium and Sium, to which it finally attaches a little cocoon, open above for the reception of 

 the posterior part of the body of the pupa. The latter, which thus sits upright in its cradle, is 

 otherwise naked, but has on each side of the fore part of the thorax eight very long thread-like 

 appendages, which also may be respiratory organs. The perfect insect emerges under water. 



TRIBE II. NOTACANTHA. 



Although the character from which the name of this second tribe of Diptera is derived, 

 namely, the presence of spines upon the posterior margin of the scutellum, is not a very important 

 one, the group itself seems to be well founded, having, as already stated, peculiarities of structure 

 and development which would ally it on the one hand with the preceding, and on the other with 

 the following division. It thus stands very naturally between the two groups. 



The group is a very well-characterised one. The antenna?, which originate close together on 

 the forehead, apparently consist of three joints ; that is to say, the first and second joints are 

 easily recognisable, but the remainder are united in such a manner as to represent a single large 

 joint, which, however, is more or less distinctly ringed. In some forms the apex of the antenna 

 bears a style or bristle. The eyes are large, and there are three ocelli. The proboscis is short, and 

 terminated by fleshy lobes, and within it there are never more than three bristles besides the 

 labrum ; but even of thess the maxillary pair are often amalgamated with the labiuin. The legs are 

 simple, and the tarsi furnished with three pulvilli. 



The scutellum, as already stated, is usually spinous, but the number of spines is variable ; 

 sometimes there are only two, and sometimes four, whilst in a considerable number of species the hinder 

 margin of the scutellum shows a whole row of small spines. Other characters have been already 

 mentioned. These insects constitute only a single family. 



FAMILY VIII. STRATIOMYID^E. 



The Stratiomyidse are a tolerably numerous family of flies, well represented in most parts of the 

 world. They may be divided into two subordinate groups, easily recognisable by the number of 

 segments visible in the abdomen. 



In the STRATIOMYIDES the abdomen exhibits only five free segments. One of the best known 

 species of this group is the Stratiomys chamceleon, a large and handsome fly (see figure on p. 84), rather 

 over half an inch long, and of a general brassy-black colour, clothed with tawny hairs; the scutellum is 

 yellow, and armed with two longish spines ; the broad abdomen is black, with two large yellow spots 

 on the first segment and interrupted yellow bands crossing the others ; the thighs are black, and the 

 tibife and tarsi tawny. The transformations of this species are very well known. The female deposits 

 her eggs on the under side of the leaf of some aquatic plant, usually the Water Plantain (.4 lisma 

 plantayo), arranging them so as to lie one over the other like tiles on a roof. The larvae hatched from 

 these eggs are elongated, widest towards the fore part, where there is a small horny head, and much 

 nan-owed towards the hinder end, at the extreme point of which the only efficient stigmata are 

 situated, surrounded by a circlet of barbed hairs which, when spread out, enable the insects to 

 suspend themselves at the surface of the water while they breathe. By means of these hairs, 

 when folded in, they can even carry down with them into the water a globule of air, which 

 then looks like a small pearl. These larvse swim by wriggling movements in which their body 

 is bent into an S-like form. Their food consists of minute aquatic organisms, and particles of 

 nutritive matter, brought to the mouth by the action of a pair of hairy palpi ; the mouth is also 



