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NEW YORK STATE MUSEUM 



This midge is abundantly parasitized in certain localities by 

 Aprostocetus diplosidis and Tetrastichus, the latter 

 being both a primary and secondary parasite. By far the most 

 important predaceous enemy of the midge is the Argentine ant, 

 Iridomyrmex humilis Mayr. These insects swarm over 

 the sorghum plants and seize and carry off the midge pupae pro- 

 jecting from sorghum seeds. A fly, Psilopodinus flavi- 

 ceps Aldr., has been observed preying upon the midges. It is 

 probable that humming birds also devour these small flies. 



Remedial measures. Johnson grass should not be allowed to 

 grow in the vicinity of sorghum fields, since it is an important factor 



Fig. 31 Con- 

 tarinia sor- 

 g h i c o 1 a, fifth 

 antennal segment 

 of male (enlarged, 

 original) 



Fig. 32 Con- 

 tarinia sor- 

 g h i c o 1 a, fifth 

 antennal segment 

 of female (en- 

 larged, original) 



in producing an early infestation. Clean harvesting, resulting in 

 the caring for and adequate destruction of infested heads, will do 

 much to reduce the number of midges appearing the following 

 season. The destruction of the early crop of seed has been sug- 

 gested as a means of eliminating a large percentage of the midges 

 and thus securing a nearly full, clean, late crop. 



Description. Egg. Length . 1 5 mm, pale pink or yellow, delicate, 

 elongate, cylindric. 



Larva. The full-grown larva is broadly oval, deep red and with a 

 distinct breastbone. 



