52 CEREAL AND FOEAGE INSECTS. 



overlapping the second outer glume and at a point midway between 

 the apex and base of the glumes. 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 larvae hatching under such conditions would 

 find their way to the ovary. 



LOCATION OF THE LARV.E. 



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 glumes. 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 per- 

 ceptibly 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 glumes, 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 

 examined, invariably shriveled and failed to hatch before the spikelets 

 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 heads to become 

 infested under natural conditions in the field, then bagging them, 

 and later dissecting the spikelets at various intervals. Thus, with 

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



