THE BLACK FLY. 



73 



68. Black Fly. 



The Simulium molestum (Fig. 68, enlarged), as the black fly 

 is called, lives during the larva state in the water. The larva 

 of a Labrador species (Fig. 69, enlarged) which we found, is 

 about a quarter of an inch long, and of the appearance here indi 

 cated. The pupa is also aquatic, having long respiratory fila 

 ments attached to each side of the 

 front of the thorax. According to 

 Westwood, &quot;the posterior part of its 

 body is enclosed in a semioval mem 

 branous cocoon, which is at first formed^ 

 by the larva, the anterior part of which 

 is eaten away before 

 changing to a pupa, so as 

 to be open in front. The 



imago is produced beneath the surface of the water, 

 its fine silky covering serving to repel the action 

 of the water.&quot; 



Multitudes of a long, slender, white worm may 

 often be found living in the dirt, and sour sap run 

 ning from wounds in the elm 

 tree. Two summers ago we 

 discovered some of these lar 

 va}, and on rearing them found 

 that they were a species of 

 Mycetobia (Fig. 70; a, larva; 

 6, pupa). The larva is remark 

 able for having the abdominal 

 segments divided into two 

 portions, the hinder much 



69 L^r - Fly smaller than the anter ior divi 

 sion. Its whole length is a 

 little over a third of. an inch. The pupae 

 were found sticking out in considerable 

 numbers from the tree, being anchored by 

 the little spines at the tail. The head is 

 square, ending in two horns, and the body is straight and 

 covered with spines, especially towards the end of the tail. 

 They were a fifth of an inch in length. The last of June the 

 flies appeared, somewhat resembling gnats, and about a line 

 long. The worms continued to infest the tree for six weeks, the 

 flies remaining either upon or near it. 



70. Mycetobia. 



