THE FLIES THAT CAUSE MYIASIS IN MAX 123 



Illinois. Minnesota. Wisconsin. Kansas. Idaho, Colorado. Washington. Palaearc- 

 tic Region: Ireland. Scotland. England. Spain. France. Netherlands, Italy. Cor- 

 sica. Sicily. Norway. Sweden. Finland, Lapland (Swedish). Denmark, Germany. 

 Austria. Hungary. Rumania, European Russia (north to Kanin Peninsula), 

 Novaya Zemlya, Azores. Algeria. Libia, Siberia (Irkutsk, Yana Valley), Kam- 

 chatka, China. Australian Region : Victoria. 



Biology and Pathogenesis. — This species breeds in various media, 

 including grasses and small grains, roots of cabbage and radishes, 

 horse manure, and decomposing vegetable matter. 



Several cases of intestinal myiasis caused by this species have been 

 reported. One which seems to be authentic was reported by Austen 

 (-5). who made determinations on the flies reared from larvae passed 

 over a period of several days by an otherwise healthy child. 



The Genus HYLEMYA Robineau-Desvoidy 



The larvae of this genus very commonly feed on a wide range of 

 plants used for food, including roots that may be eaten raw. It is 

 highly probable that from time to time living larvae may be ingested, 

 though there is no proof of their ability to cause digestive disturbances 

 or to survive the conditions found in the human digestive tract. Some 

 members of this genus, such as H. furcata (Bonehe). H. bra.ssicae 

 (Bouche). and H. antigua (Mg.) (H. ceparwm (Mg.)), have been 

 mentioned in connection with intestinal myiasis, but confirmation of 

 the records is lacking. 



The Genus SYINTHESIOMYIA Brauer and Bergenstamm 



This genus contains but a single species. The arista is bare; the 

 propleura and pteropleura are bare, the prosternum distinctly pilose; 

 there are two presutural and four postsutural dorsocentrals; there are 

 three sternopleurals, the lower one being situated very close to the 

 hind one: the metathoracic spiracle is much longer than broad; the 

 wing veins are bare above and below ; vein m^+2 bows strongly forward, 

 as in ILusC'iiG. and reaches the costa before the wing apex: the anal 

 vein is long but does not attain the wing margin, even as a fold. 



SYNTHESIOMYA NLDISETA (van der Wulp) 



Synonyms. — Synthesiomyia brasiliana Brauer and Kergenstamni ; Synthesi- 

 omyia analis (Macquart). 



Recognition Characters. — Adult: This is a grayish fly, about 10 mm. in 

 length, with a striped thorax, a somewhat tesselated abdomen which is yellow 

 at the apex, and bright orange-y^ilow antennae and palpi. Superficially it 

 resembles a Xarcotjltwju. but the bare arista and the lack of hypopleural bristles 

 will at once distinguish it from members of that genus. Larva: The larva is 

 of the usual muscoid type. In the first instar there are characteristic tubercles 

 on the eighth abdominal segment: one is median, posterior to the anus, and 

 spined ; there are three pairs of unspined tubercles in a ventrolateral position. 

 In the second instar the tubercles are more prominent and all are spined. The 

 third-stage larva is 7-15 mm. in Length, is relatively thick, and creamy white. 

 The spinulose tubercles are prominent; in addition, there are six larger and 

 two smaller sensory papillae surrounding the spiracles (fig. G7). The posterior 

 spiracles are black and prominent (fig. <'> s > : they have no peritreme, and the 

 slits are S-shaped; the button is difficult to distinguish. The anterior spiracles 

 have four to seven processes. 



Geographical Distriiutiox. — Nearctic Region : North Carolina, Georgia, 

 Florida, Texas, Arizona. Neotropical Region: Mexico, Nicaragua. Costa Rica, 

 Panama, Canal Zone, Bermuda, Dominican Republic, Cuba, Virgin Islands, Gala- 



