NO. I BLACK FLIES OF GUATEMALA — DALMAT 3II 



The eggs, larvae, and pupae have been found on the following 

 plants : 



Axonopus cofnprcssus (Sw.) Beauv. Renealmia sp. 



Coix lachryma-jobi L. Hyptis sinuata Pohl 



Tradescantia guatemalensis C. B. Clarke Legurainosae 



Tradescantia covtmelinoides R. and S. Acanthaceae 



Tripogandra cumanensis (Kunth) Woodson Compositae 

 Heteranthera reniformis R. and P. 



Species of black flies often found breeding (in order of frequency) 

 along with S. metallicum are (Appendix III, table 33) : 



5". callidum S. veracruzanum S. pulverulentum 



S. downsi S. jobbinsi S. jacumbae 



S. rubiciindulum S. smarti S. acatenangoensis 



S. mexicanum S. exiguum S. yepocapcnse 



S. ochraceum S. capricornis S. parrai 



Like S. ochraceum, the adults mate very soon after emergence, the 

 spermatozoa being stored in the spermatheca. For the eggs to develop 

 into larvae, the females must obtain blood meals prior to oviposition. 

 Fertilization occurs as the eggs pass the opening of the spermatheca in 

 the process of oviposition. The female oviposits in two manners. If 

 the current is very rapid, it approaches the appropriate leaf at the 

 surface of the water and deposits an egg without apparently landing ; 

 it then hovers above the leaf and returns to the same spot to deposit 

 the second egg. The eggs are laid one in 2 seconds, contiguous to each 

 other, but forming no general pattern and never overlapping. Should 

 the stream be relatively slow-moving, the fly will actually land on the 

 leaf to deposit the eggs. In this case, after each egg is laid, the fly 

 moves about somewhat before returning to the area to lay the next 

 egg. Often several females, at times as many as 30, have been seen 

 ovipositing on a single leaf of Renealmia sp. One fly can deposit from 

 150 to 500 eggs in one mass. This species prefers the hours from 

 5 p.m. to 6 p.m. for oviposition, although it has been observed on 

 several occasions as early as 3 p.m. The first-stage larvae emerge in 

 from 3 to 20 days and soon arrange themselves in the smaller currents, 

 most frequently attaching to leaves of plants, but at times to stones 

 and rocks. The larval development follows that of 5^. ochraceum, with 

 pupation occurring after 6 to 20 days. The cocoon is woven on leaves 

 or stones in a manner similar to that of 6". ochraceum. If the case is on 

 a flat surface, it bears a winglike lateral extension on each side ; if on 

 rocks, inserted next to the vein on the underside of a leaf, or on a 

 round twig, it may lack the extensions. The adult emerges in from 

 4 to 10 days, the females being capable of surviving at least 85 days 



