3032 



THE JOINTED ANIMALS 



Limpopo. Fortunately, it is not universally distributed throughout the country, 

 being somewhat local in its distribution, and inhabiting definite tracts of land, 

 corresponding with the beds of rivers, from which it does not appear to spread 

 to any great distance. 



Another group of flies constitutes the subfamily Tachinince, of which the best- 

 known examples are the spiny flies (Tac/rina*), so called on account of the thickness 

 of the bristles with which their bodies are clothed. Of stout and robust build, these 

 flies present a great resemblance to blowflies and their allies, but have the bristles 

 of the antennae naked, or feathery only at the base, and the scales covering the bal- 

 ancers of larger size. The larvae, like those of the Conopidae, live parasitically upon 

 other insects, such as beetles, grasshoppers, and caterpillars. The great spiny fly 

 {Echinomyia grossa) , rather a local species, is the largest representative of the fam- 

 ily found in Britain. It is about two-thirds of an inch long, with a short, broad, 

 oval abdomen; the shining black of its body being relieved by the reddish-yellow 

 color of the head and the base of the wings. The allied species (E. ferox} repre- 

 sented in the illustration is brownish, with the abdomen tinted with red at the sides. 



I 



Belonging to the same subfamily is the Australian fly, 

 Rutilia, remarkable among the order for being ornamented 

 with bright metallic-green spots. By reason of their ex- 

 ternal form and general coloring the flies of the subfamily 

 Anthomyince appear to the casual observer to be nothing but 

 ordinary house flies; but they may be distinguished from 

 the latter by the absence of the apical transverse vein on the 

 wing (marked d on the figure of the fly's wing on p. 3011). 

 The scales, moreover, which cover the halteres are very 

 small, and lead up to the condition found in those flies in 

 which they are absent. The larvae, which differ from those 

 of the house flies and blowflies in being covered with spines, live on plants of various 

 kinds, those that have attracted the most attention being the species that attack 

 cultivated vegetables, such as onions, cabbages, lettuces, radishes, and the like. 

 Those members of the family having no scales covering the balancers and assigned 

 to the subfamily Trypetince are generally of small size, many being very obnoxious 



on account of the damage inflicted by their larvae on 

 various marketable vegetables. Of the numerous 

 species it is only possible to notice a few. The first is 

 the painted- winged asparagus fly (Platyparea p<ztilop- 

 tera], which, as its name indicates, has variegated 

 wings, and attacks asparagus. The male is smaller 

 than the female, as shown by the length of the lines in 

 the figure, and the latter sex may be recognized by the 

 possession of a long ovipositor, by means of which 

 she deposits her eggs between the scales of the head 

 of the asparagus. The laying takes place about the 

 beginning of May, and in two or three weeks, according to the season, the eggs 

 hatch, and the larvae 'burrow into the stalk of the plant. In a fortnight or so the 



SPINY FLY (Echinomyia 

 ferox} , WITH LARVA 



AND PUPA. 



(Natural size.) 



ASPARAGUS FLY, * male; f female, 

 (a) Front view of head. 



