BITING MIDGES — WIRTH AND BLANTON 247 



upper Amazon by the Andean uplift in the Tertiary period. Chapman 

 also found a remarkable similarity in the subtropical bird fauna of 

 Colombia to that of Costa Rica and western Panama, with about 60 

 species in common. He could explain this similarity only by postulat- 

 ing a former continuous extension of the Andes Mountain system 

 at altitudes not less than 5,000 feet throughout Panama. The tem- 

 perate avifauna of Costa Rica, on the other hand, is not closely re- 

 lated to that of Colombia, indicating that this mountain connection 

 never exceeded a height of 9,000 feet. The subsidence of the Panama 

 Isthmus to its present elevation in what Chapman called the Panama 

 "fault," has resulted in the extinction of the subtropical fauna in the 

 intervening area except for a few relicts such as the Culicoides we 

 have reported from Cerro Campana and El Valle. The fauna of the 

 arid tropical zone of Panama, according to Griscom (1935), is an 

 extension of the Central American faunal subregion, and not closely 

 related to that of South America, except for the gallery forest species, 

 which find their relatives in the arid Dagua and Magdalena areas 

 and the arid north coast of Colombia. 



Breeding Places 



General accounts of the breeding habits of Culicoides are given 

 by Carter, Ingram, and Macfie (1920) and Hopkins (1952) for West 

 Africa; Hill (1947), Lawson (1951), and Kettle and Lawson (1952) for 

 Britain; and Williams (1951) for North America. Little rearing work 

 has been done on Neotropical Culicoides, the only important references 

 being Lutz (1913), Painter (1926), Fox (1942), Carpenter (1951), and 

 Woke (1954). The known breeding places of Panama Culicoides 

 are given in table 3. 



Favorite larval habitats include the following: mud and sand at 

 stream, pond, and ditch margins or margins of practically any small 

 body of still or slowly running water; compost piles, rotting leaf mold, 

 and other vegetable matter that stays wet constantly. In the tropics 

 larvae may be found in rotting banana stalks and wet, decaying 

 fruits and stems of plants; mud or wet organic material in or at the 

 sides of rot holes in trees, stumps, bamboo joints, coconut shells, 

 rotten boat bottoms, and the like; wet debris in the leaf or flower axils 

 of waterholding plants such as pitcher plants, aroids, bromeliads, 

 Heliconia, and Pandanus; and crab holes. Picado (1913) showed 

 heleid larvae that resemble Culicoides taken from bromeliads in Costa 

 Rica. Ryckman and Ames (1953) reared Culicoides copiosus Root 

 and Hoffman from rotting stems of the cactus Cereus gigantea in 

 Arizona. 



