REPORT OF THE STATE ENTOMOLOGIST I917 IO7 



1908 Felt, E. P. N. Y. State Mus. Bui. 124, p. 393 



1909 Ent. Soc. Ont. 39th Rep't, p. 43 



1909 Herrick, G. W. Ent. News, 20:116-18 



1909 Trehern, R. C. Ent. Soc. Ont. 39th Rep't, p. 47-49 



1910 Dean, W. H. Econ. Ent. Jour., 3:205-7 



1910 U. S. Dept. Agric, Bur. Ent. Bui. 85, pt 4, p. 39-58 



1913 Newell, Wilmon & Barber, T. C. U. S. Dept. Agric, Bur. Ent. Bui. 

 122, p. 69-71 (I r i d o m y r m e X h u m i 1 i s preying on) 



This species was first observed in the south in October 1895. 

 specimens of infested heads of Sorghum vulgare from Dill- 

 burg and Montgomery, Ala., being then received at the Bureau of 

 Entomology. This insect appears to be widely distributed in the 

 south at the present time, having been recorded from North Caro- 

 lina, South Carolina, Georgia, Louisiana, Texas, Arkansas, Indian 

 Territory, Missouri and Kansas. This midge prevents, in the 

 majority of cases, the maturing of a profitable seed crop in the 

 estimation of W. H. Dean, who has made a special investigation of 

 the pest. The adult may be recognized by its orange-red abdomen, 

 in connection with the fifth antennal segment having the basal 

 portion of the stem with a length one-half greater than its diameter 

 and the broadly and triangularly emarginate dorsal plate. 



This insect, it has been found, subsists, in addition to the many 

 varieties of sweet sorghum, upon broom com, kafir corn, Johnson 

 grass and Milo miaze. Mr Dean reared one adult from fox -tail 

 grass, Setaria glauca, and Mr Ainslie obtained it from 

 another grass, Sieglingia seslerioides. 



Life history. The midges appear in early spring, breeding at first 

 in Johnson grass, and by the time sorghum has headed, the midge 

 has become sufficiently abundant to produce a serious infestation. 

 The eggs are deposited by the parent midge within the floret and 

 usually near the apex of the ovary. Infested heads of sorghum have 

 a characteristic flattened appearance, the ovary being blackened 

 and shriveled. The life of the midge in confinement is stated to 

 be approximately 24 hours, though females, if allowed to oviposit, 

 may live about 48 hours. From a dozen to upwards of 100 eggs 

 were found upon dissection. Breeding may continue throughout the 

 season as long as there are any heads in which to oviposit. The 

 insect hibernates as a larva within a delicate, muddy brown envelop 

 somewhat like the " flax seed " of the Hessian fly. The activities 

 of this insect, like the Hessian fly, Mayetiola destructor 

 Say, are evidently closely correlated with the condition of vegetation, 

 breeding continuing so long as a suitable food supply exists. The 

 life cycle may be completed in from 14 to 20 days. 



