52 CEEEAL AND FORAGE INSECTS. 



overlapping the second outer glume and at a point midway between 

 the apex and base of the seed. An immediate dissection of these 

 seeds revealed the eggs situated upon the inner surface of the second 

 outer glume almost in view from a superficial examination. It is 

 extremely doubtful if larva? hatching under such conditions would find 

 their way to the ovary. 



LOCATION OF THE LARVAE. 



When hatched the larvae immediately make their way to the ovary 

 and are invariably found lying directly against the latter within the 

 delicate palet . Their position remains unchanged throughout growth, 

 their length being parallel to the ovary and the head pointing to the 

 apex of the seed. The larvae, expanding their full length close against 

 the ovary, sap the juices. A faint discoloration of the ovary takes 

 place at the point of contact with the larva shortly after the latter has 

 taken its normal position. This discoloration deepens perceptibly 

 as larval growth increases, and during the full-grown stage the larva 

 is set in a tiny depression, caused by the draining of the plant juice 

 by the larva at that point. 



LOCATION OF THE PUPA. 



The pupa is formed in exactly the same position as has been occu- 

 pied by the larva during its growth and development. The head is 

 directed toward the apex of the seed, to which point it works itself 

 preparatory to emergence. 



NUMBER OF GENERATIONS. 



There are no well-defined broods or generations. From early spring 

 until late fall the midge may be found in any stage from egg to adult. 



THE LIFE CYCLE. 



The greatest of difficulty has attended the determination of the 

 periods required for the egg, larval, and pupal stages. Under the most 

 careful manipulation newly deposited eggs, when located and exam- 

 ined, invariably shriveled and failed to hatch before the seed glumes 

 opened and the eggs were exposed to atmospheric influences; conse- 

 quently, attempts to watch newly deposited eggs until the date of 

 hatching have been so far unsuccessful. The same difficulties apply 

 to raising larvae to maturity under artificial conditions. The pupae, 

 however, are more successfully handled, as exposure to air does not 

 seem to affect their development and the emergence of the adult. 



The method finally adopted consisted of permitting seed heads to 

 become infested under natural conditions in the field, then bagging 

 them, and later dissecting the seed at various intervals. Thus, with 

 a large number of heads infested and examined at different periods, 



