THE STRAIGHT-SEAMED FLIES 3015 



Ceylon are uninfluenced by the same considerations which restrained those of the 

 Nile under the successors of Cambyses." An interesting question arises in connec- 

 tion with mosquitoes as to the nature of the food of the vast hordes of them 

 that frequent the tropics. It is true that the females alone bite; but the proboscis 

 is a highly perfected organ for piercing and sucking, and it might be supposed that 

 it is extensively used for the purpose. Yet it has been pointed out that the vast 

 majority of mosquitoes can never taste mammalian blood. In various places, such 

 as parts of India for example, mosquitoes are found in swarms in spots never visited 

 by human beings, and in which there are no large mammals. It has been suggested 

 that, failing to obtain blood, mosquitoes support themselves on the juices of plants, 

 but no observations in support of this have been recorded. 



The daddy longlegs ( Tipulidce} contain the finest species of this 

 1 Longlegs division of the order; the largest European form being the giant 

 daddy longlegs ( Tipula gigantea} , which has its wings clouded with 

 brown, and measures about one and one-fourth inches in length. Much larger 

 kinds are, however, met with in Burma and China. The short and fleshy proboscis 

 is not adapted for piercing, but merely for absorbing fluids; and the antennae are 

 not feathery as is so often the case in the gnats and midges, although in the species of 

 the genus Ctenophora which are of stouter build, and often brightly colored black 

 and yellow, thereby resembling some of the sawflies the antennae are pectinated 

 in the male. In this family the eggs are laid and the larvas undergo their growth 

 and change of form either in water or earth. The females of two of the commonest 

 British species ( T. oleracea and T. paludosa) may be seen in summer and autumn 

 flying about meadows and depositing their eggs here and there in the soil. When 

 hatched, the larvae start feeding upon the roots of grass and corn, thereby doing 

 considerable damage to farmers and gardeners, to whom they are known by the 

 name " leather jackets." 



The true midges belonging to the family Chironomidce are nearly 

 allied to the gnats, with which they are often confounded; but the 

 mouth parts are rarely adapted for piercing, the proboscis being short and soft. In 

 the genus Cetatopogon the jaws of the females are, however, lancet shaped, and 

 capable of drawing blood. The little black midge that in the summer settles upon 

 the hands and face and inflicts a sharp prick belongs to this genus. But the best- 

 known member of the family is the plumed midge (Chironomus phimosus) , which 

 on summer evenings may be seen dancing in swarms along roads and lanes. Its 

 name has been given to this species on account of the beautiful feathery-like 

 antennae of the male. In connection with this species a case of luminosity has 

 recently been recorded. An observer in Russian Asia found on the shores of Lake 

 Issyk Kul a number of examples of this midge, and of an allied form belonging to 

 the genus Corethra emitting a phosphorescent light. Failing to discover any 

 luminous organ he came to the conclusion that the light was due to the presence 

 in the insect of multitudes of parasitic bacteria, an opinion strengthened by the 

 observation that the shining individuals were sluggish and never seen on the wing. 

 The fungus midges (Mycetophilidce) take their name from the fact that the larvae 

 of most species feed upon fungi of various kinds. The perfect insects, which fre- 



