3020 



THE JOINTED ANIMALS 



process of reproduction, and so the phenomenon continues through the cold months 

 of the year. At the beginning of the summer the process comes to -an end, and 

 the larvae fulfil their destiny and give rise to mature insects in the ordinary manner. 

 The two families now to be mentioned have been termed the 

 es ' e c ' anomalous, or fly-like Nematocera, since although their antennas are 

 many jointed, they are shorter than in the foregoing families, and their limbs and 

 bodies instead of presenting the aspect of those of the gnats and midges, are shorter, 

 thicker, and closely approach in this respect those of ordinary flies. To the family 

 Simuliidfe belong the minute "sand flies" of the tropics, which surpass even the 

 mosquitoes in their venomous bite, and on account of their minute size are far more 

 difficult to cope with. In these insects the mouth parts are 

 adapted for piercing; and the early stages of life are passed in 

 water. The best-known European example is the Columbatsch fly 

 (Simulia columbatzensis) , taking its name from a village in Servia, 

 where it is a great pest. In fact, in all the countries irrigated by 

 the lower waters of the Danube, this fly, hardly larger than a 

 COLUMBATSCH FLY. flea, abounds; and it is said that in Hungary cattle and sheep 

 (Enlarged.) have been destroyed by hundreds owing to the tortures they have 

 suffered from these insects . The little flies creep into the eyes, 

 nose, and ears of their victims, and there gorge themselves with blood, driving 

 the poor beasts to the verge of madness by the intolerable irritation of their 

 bites. 



The second family of the group {Bibionidee) contains the well-known St. 

 Mark's fly (Bibio marci}, a large, black, hairy, slow-flying insect, common in spring, 

 and taking its name from its being fre- 

 quently seen in numbers on or about St. 

 Mark's Day. The two sexes differ greatly 

 in many respects, the male having the 

 wings clear, whereas those of the female 

 are dusky; again the eyes in the male are 

 so large that the entire head seems to be 

 composed of them, but in the female these 

 organs are small and wide apart. This 

 distinction, however, although not usually 

 in so pronounced a form, is observed 

 between the two sexes of many flies. The 

 eggs in number amounting to about one 

 hundred and fifty are laid on the ground 

 among vegetable or animal debris, on which 

 the larvae subsequently feed. In the grub 

 the head has neither eyes nor recognizable antennae, but the mouth parts are dis- 

 tinct; the body consisting of twelve segments, each of which is surmounted by. a 

 row of bristles. After passing the winter in the soil in an immature state, the 

 larvae ascend to the surface in the spring, and take on the pupal stage, from which, 

 after about a fortnight's time, the perfect insects emerge. 



ST. MARK'S FLY. 



(Natural size, with enlarged figure of larva 

 and pupa.) 



